REFERENCE COMPONENTS

LINE STAGES

UPDATED MAY 2017

INTRODUCTION

CLASS A

CLASS B

CLASS C

THE BOLERO TEST

OTHER INTERESTING LINE STAGES

READERS LETTERS

INTERNAL LINKS

INTRODUCTION

Our discovery, experience and evaluation of "The Truth" Line Stage has forced me to question the opinions and advice in this section, so they have been removed for now. I will add editorial content to this section when I am once again confident of its veracity, consistency and perspective.

Top

CLASS A

The Best "Hybrid" and Overall Line Stage we've heard...

"THE TRUTH"

I believe "The Truth" line stage is the most important audio component available today. It does not have universal applicability and it also has some impractical features but, within its general component class, it stands by itself, sui generis and "one of a kind". More than that, "The Truth" line stage can even be thought of as a "tool" and/or Reference for both audio designers and those serious audiophiles interested in finally learning the true (no pun intended) capabilities, and limitations, of both their sources and their current line stages. First, some important perspective...

The Basic Functions of a Line Stage

A traditional (active) line stage has four basic functions. In contrast, a "direct connection", from the signal source directly to an amplifier, has no functions by definition. These are the four functions:

1. Gain/Energy (to amplify the original signal)

2. Volume Attenuation (to optimize the volume level)

3. Output Buffer (to reduce, if not eliminate, the problematic effects of incompatible input/output impedances and/or lengthy signal cables)

4. Source Selection (optional, if there is more than one source)

A traditional active line stage should have all four functions, which gives it universal applicability. This means that it should work optimally in all systems, regardless of the sources, cables and/or the amplifier requirements. The Coincident Statement Line Stage (CSLS) is still the finest traditional active line stage I've heard.

A passive line stage will always have Volume Attenuation and sometimes Source Selection as well. The EMIA is still the best passive line stage I've yet heard.

"The Truth" line stage is unique, and may even be described as a "Hybrid". It has every basic function with the sole exception of extra Gain.

System Requirements and the First Responsibility

Some audio systems require gain in their line stage for one or more sources to reach a satisfying volume level. Other systems have sources with the necessary volume, so they don't require any gain. However, sheer volume, by itself, is never the only objective. The quality of the signal is equally important. The first responsibility of a serious audiophile is to discover the capabilities and requirements of their system, with certainty, and to also do so safely. This is not easily done, however...

When I first found myself in this same position decades ago, I devised "The Bolero Test" (see link below), which safely provides the listener the music and time to discover whether a source has both the volume, and also the sound quality, to avoid using an active line stage. While this test still has validity, "The Truth" line stage has now changed the implications of the results (a literal "game changer"), which is discussed below. Meanwhile, the entire, and complex, active versus passive line stage issue must also be addressed at this time.

Common Misconceptions and Misunderstandings of Line Stages

If one visits websites with audio discussion groups, such as Audio Asylum and especially Audiogon, you will find numerous threads concerning the benefits and/or deficiencies of active versus passive line stages. There are usually a number of adherents on either side, with most of them talking past each other, and their opinions mainly based on a very limited number of experiences. The most common and consistent claim of active line stages fans is that their favorite models will "improve" the original signal, so it's even better than it was at the output of the source. Unfortunately, this is IMPOSSIBLE to achieve, both technically and by definition. A source, or the original signal, is never able to be "improved".

Why? Consider first the obvious implication. If it was actually possible for an active line stage, or any component, to literally improve the original signal, then more models of that same component could be further used, again and again, in series, until the sound was better than "live" or the original recording. In short, why would anyone ever stop after the first improvement? It would only make sense to go on and on until space and/or money ran out. No component can remove what shouldn't have been in the signal in the first place (distortions), or restore the musical information that was once there, but now is lost. However, there must be some rational explanation for the (obvious and indisputable) better sound usually heard when using an active line stage?

An active line stage's better sound (versus a passive) is not an illusion or personal "taste". The sound is better because the original signal has been "actualized", making it a better "fit" with the amplifier's requirements. Why is this necessary? The direct signal from the source usually requires some sort of "assistance" or transformation before it can properly drive the power amplifier. This signal buffering is the critical function of an active line stage, with gain usually being a "bonus". Proper buffering allows the original output signal to fully satisfy the input requirements of the power amplifier. The goal, or ideal, is to achieve these functions with as few noticeable sonic problems as possible.

Active Versus Passive Line Stages - A Mainly Circular and Fruitless Argument

Only when the original signal source has the required energy to directly drive the power amplifier, without any sonic compromises, can a passive line stage ever be used with complete success, since the only function remaining at that point is signal attenuation. This basic technical fact is why audiophiles talk past each other when they argue which is better; passive or active. This is because the actual results completely depend on the specific system in question; in particular the source's energy output and the amplifier's energy input requirement.

Those audiophiles who have the sources with the required energy (a minority), will not be able to understand how anyone would want to listen to the inevitable sonic degradations of any active line stage, when there are no corresponding sonic benefits. Meanwhile, those audiophiles whose sources do not have the required energy (a majority), will not be able to understand how anyone would prefer to avoid some relatively minor audible problems while simultaneously ignoring the much larger and more easily noticeable sonic benefits they are experiencing. Both sides are undeniably correct, because they are experiencing two very different realities, though all of their experiences are consistent with the laws of acoustics and electronics.

This brings us to "The Truth" line stage, whose unique design meets the most demanding requirements of both the active and passive camps, and to an unprecedented degree. "The Truth" line stage even changes the implications of "The Bolero Test" results by eliminating "Sound Quality" as an issue. Only the volume level results are still relevant with "The Truth", because of its rare ability to optimize the sound quality of the even the weakest sources.

The Unique Design of "The Truth" Line Stage

"The Truth's" design consists of two key elements. First is the volume control, which uses Light as an attenuator, in contrast to a common resistor or a transformer. There are other line stages which also use light, such as the Lightspeed and the LDR from Tortuga Audio (see links below), though "The Truth" purportedly uses light in a different manner than the other two. Unfortunately, I am incapable of describing the technical differences between their respective methods of using light, let alone analyzing them. (I also believe Melos was the first audio manufacturer to use light in some capacity to change the volume, more than 20 years ago now, though I had no first hand experience with that ground breaking preamplifier.)

"The Truth" has another unusual design element; it uses solid-state buffers in an unique manner. The end results are an ultra-high input impedance as well as an ultra-low output impedance. I am not able to separate the distinct audible effects of these different elements, but I am still convinced that the use of these buffers is one of the keys to explaining the unique performance abilities of "The Truth". ("The Truth's" third basic function, Source Selection, which is optional, is nothing special and is irrelevant to its ultimate performance.)

"The Truth" has no On/Off switch. It is always "On" when it is plugged into the AC wall socket. It doesn't draw much power and doesn't get hot, or even warm, to the touch. It took around 2 days of continual play for it to sound its best.

The Unprecedented Performance of "The Truth" Line Stage

From a certain perspective, "The Truth" is the most difficult component I've ever had to describe. It's like it isn't even "there", which, of course, is the highest compliment imaginable for an audio component (or should be). It has the rare distinction of earning the three words I've described in the past (see "My Audio Philosophy") as highly important and the most neglected by audiophiles: "Indescribable", "Unpredictable" and "Surprising". It also deserves one of my associate's highest accolades, as it sounds like "Nothing".

Still, far more details and specifics are required to fully understand and appreciate the unequalled level of performance of "The Truth". So, I will compare "The Truth" to the two most formidable line stages that I know of at this time:

1. The Coincident Statement Line Stage (CSLS), which is active,
2. The EMIA Transformer based volume control, which is passive, and as a bonus, the most difficult test of them all, a
3. "Direct Connection", which is where we will start.

Vs. "A Direct Connection"- The ultimate test. This is a preliminary report because I'm in the process of switching the signal cables in my system, and the results of these switches may also alter the results of this comparison as well. At this time though, this is what I can report: "The Truth" is now the closest I've ever heard to sounding "direct" or "naked" (a term an associate uses). Let me explain...

As I reported back in 2012, the (passive) EMIA sounded closer to a direct connection than even the outstanding CSLS. This made perfect sense since the CSLS is an active line stage, though both of these models use transformers to change the volume. "The Truth" is even more "direct" and "naked" sounding than the EMIA, and I believe it will take some subjective numbers to best describe the "sonic gaps" that I observed between them:

Direct Connection- 100
"The Truth"- 97
EMIA- 93
CSLS- 90

Caveat- The above scale, numbers and gaps have been expanded by around 100% to make them easier to understand. In reality, the subjective numbers, starting with the CSLS, would be approximately 95, 96.5, 98.5 & 100.

Assume a "direct connection" is "100" (perfect), and the CSLS is a "90". Using this expanded scale, I would then give the EMIA a score of "93". While this is closer to 100 (direct), it's still closer to 90 than to 100, so the EMIA sounds more like the CSLS than to a direct connection. Again using this same scale, "The Truth" receives a score of "97", which is not only closer to a direct connection than the EMIA, it also sounds more like a direct connection than it sounds like the EMIA or the CSLS. This is a subtle but important distinction.

Vs. The EMIA- I haven't heard the EMIA for more than 3 years, but I am very familiar with how it sounds compared to the CSLS, so an extrapolation is not that difficult to make. The EMIA, as an outstanding passive line stage, did less harm to the signal than the CSLS or any active line stage I've heard for that matter. However, without the gain and especially the buffering functions of an active line stage, the EMIA is totally dependent on the source having the required energy to drive the amplifiers. In my Reference System (when bi-amping), and for most systems in my experience, the source will not be up to the task. However, what if the source does have the required energy, how then does the EMIA compare to "The Truth"?

"The Truth", as already stated above, is somewhat more direct, immediate and naked sounding than even the EMIA, which is an outstanding accomplishment. "The Truth" is faster and also sounds more extended, in both frequency extremes, than the EMIA, and it's more dynamic as well. The soundstage is around the same size for both, though "The Truth" has somewhat better focus. While the EMIA has around the same input and output gain, "The Truth" loses around .5 db, which is minor but must be mentioned. "The Truth" can also drive two stereo (4 mono) amplifiers at the same time, even with a weak energy source (such as my Jadis JP-80), as well as any length of cables.

Vs. The Coincident Statement Line Stage- This is an even more interesting comparison, because (unlike the EMIA) the CSLS does have the ability to drive multiple amplifiers, with any source, and it also has gain, unlike either the EMIA or "The Truth". However, there is always a sonic price to pay for gain, and while the CSLS keeps that "sonic price" smaller than any other active line stage I've heard, it still exists. Is it unfair to compare a line stage with gain to one with no gain? Maybe, but it must be done for the sake of perspective and, besides, I already directly compared the EMIA to the CSLS almost 4 years ago, so this particular comparison, gain versus no gain, is not setting a precedent for this website. Now for the details...

Compared to the CSLS, "The Truth", as stated above, is more immediate, direct, cleaner, faster and more transparent. "The Truth" also has a lower sound-floor and is more extended at both frequency extremes. The CSLS's bass is outstanding, but "The Truth" is even better. The CSLS's dynamic contrasts are outstanding as well, but it's still not equal to "The Truth". The soundstage is around the same size for both components, but "The Truth" again has superior focus. Both components can be accurately described as natural and neutral, but "The Truth" has an advantage here as well.

Summarizing the Unprecedented Performance of "The Truth"

I only have one criticism of "The Truth's" sonic performance at this time; it still doesn't possess all the immediacy and "directness" of a direct connection, which means it is still not "perfect", but it comes closer than any component I've heard. I realize this is a nitpick, but "The Truth" has left me no other option. Other than that, "The Truth" is equal or superior in every sonic attribute I can think of, and it's almost always superior. The specifics are important, and this is especially relevant with "The Truth":

"The Truth" is the most immediate, cleanest, fastest and transparent electronic component I've ever heard. These are the first qualities I observed during the initial listening audition.

"The Truth" has the lowest sound-floor of any electronic component I've heard. It has longer decays, a greater sense and feel of the recording space and it also reveals previously hidden subtle dynamic inflections.

"The Truth" has the most extended frequency extremes.

"The Truth" is also the most natural and neutral electronic component in my experience. Anyone who thinks "natural" is strictly "relative" hasn't heard "The Truth". This almost extreme sense of naturalness is present in the entire frequency range.

"The Truth's" electronic character is amazing small and so are the corresponding colorations. It even matches the finest purely passive components, like the EMIA, in this area. Because of this, "The Truth" exposes electronic colorations that I have considered "normal" in the past.

"The Truth" is the most dynamic line stage I've heard, with a convincing and uninhibited quality I've never experienced before, continually surprising me even with music I am overly familiar with. It is so dynamic, that what was considered the normal volume level may have to be changed.

"The Truth" is also the most detailed, individualized and least homogenized line stage I've heard. Example- Lyrics almost always become more intelligible with "The Truth".

The soundstage of "The Truth" is not larger than the other top line stages I've heard, but it does have superior focus and separation.

My system is more cohesive than it has ever been in the past, especially between the Pure Reference Extreme Monitors and Subwoofers. I believe this is primarily because of the improvements in the bass frequencies, which leads us to...

The bass reproduction of "The Truth" deserves special attention. It is simply state of the art in extension, control, texture, linearity, detail and primal force. One LP had me almost losing control of my bowels while playing it with "The Truth". This record went from being superb to truly frightening (though it was not just "The Truth" alone that was fully responsible for this profound change). From a different (though equally telling) perspective, until I heard "The Truth" in my system, I was unaware of just how outstanding the Jadis JP-80, the Dragon II amplifiers and the Coincident Subwoofers actually were in reproducing the bass frequencies. They were always "special" for sure, but "The Truth" was able to take them beyond that.

I need to be clear that most of these improvements are not "dramatic" individually. The relative performance of both the EMIA and the CSLS are at too high a level to allow a casual and honest use of that term. However, almost all of these improvements are easily noticeable, even without listening for them, and they are also cumulative, so they still must be described as significant.

Explaining the Unprecedented Performance of "The Truth"

"The Truth" is a simple design, so while I am not a technician, attempting to explain the reason(s) for its performance is not that difficult. "The Truth" has two buffers (input and output) and one light-based attenuator in its signal path. It's obvious that none of these devices is adversely effecting the signal. In fact, they all seem to completely disappear, so this must be the explanation for "The Truth's" unprecedented performance.

"The Truth" also demonstrates, to the point of conviction, that "Light" is sonically superior to a transformer in volume attenuation, just as a good transformer is superior to even the finest resistor in my experience. I was initially concerned with the (two) buffers, since they are solid-state, but the actual sonic results refute any prejudice I had. In fact, nothing else I've heard in the past, tube or transistor, can equal the degree of their innocuousness.

The buffers are also the reason why "The Truth" can easily deal with both the lowest energy sources and the most demanding power amplifier input requirements, simultaneously, and even the longest signal cables as well. No other light-based volume attenuator I'm aware of can make this same claim.

Improving "The Truth"

"The Truth", right out of the box, did not sound quite like I described above. I made several changes, nothing major, which made it both practical to use in my system, while also elevating its performance to new heights. There are four changes, though not all of them may be applicable to all users. It will depend on the particular system and set-up.

1. Isolation Plate- I placed a metapolymer isolation plate below "The Truth". The sound became a little purer, relaxed and better focused. It also lowered the sound-floor. Component isolation is common these days for serious audiophiles, so this is nothing special or unexpected.

2. Internal grounding of the (IEC jack) "earth" pin- "The Truth" was quiet with the APL digital player, but it had a loud hum with the phono source, and nothing I did could eliminate it. I later noticed that the internal IEC jack earth pin was unattached, so I connected it to the chassis. This eliminated the hum and it also slightly lowered the sound-floor as a bonus. The audibility of hum is almost always dependent on system/home grounding, so this may not be a problem with other systems.

3. AC power cord switched to Coincident CST and then Statement- "The Truth" comes with a 6 foot generic power cord. I replaced this with a 2 foot Coincident CST power cord and then later with a 2 foot Statement power cord. This was the largest improvement, with the exception of eliminating the hum of course. I believe "The Truth" requires a high quality power cord in the most revealing and demanding systems. I realize that a good quality power cord could cost a high % of the original investment, but it is well worth it in the long run.

4. 10 lb. lead weight placed on top of chassis- The metal case of "The Truth" is somewhat flimsy, so I added the weight, with damping materials placed between the weight and the case. The result was only a tiny improvement in purity and image focus, but it cost nothing so why not?

Is it possible to further improve "The Truth"? I believe so, but this would require some internal modifications which are mainly beyond my expertise at this time (see the website, link below). One fantasy I have is to hear a model of "The Truth" with a dual-mono power supply.

Some Minor Quibbles?

There is an issue with the volume control of "The Truth". It is the most sensitive I've ever experienced, by far, and to make matters worse, the dynamic range of "The Truth", also unprecedented in my experience, makes the detection of an optimum volume level that much more critical and difficult to find. Finding the optimum volume level with "The Truth", especially with a dynamic recording, is similar to finding the optimum VTA for a record, and that is not an exaggeration. However, I still prefer this volume control, especially when considering the alternatives. What?...

The ultra-sensitive volume control of "The Truth" is continuous, while most serious line stages (including the EMIA and CSLS) have stepped controls. For me, this is an important if not critical distinction. Why? With "The Truth", it's always possible to find the ideal volume level, even if it isn't an easy process. This is not the case with stepped controls, which usually have 1 to 2 db increments. With them, you must learn to live with an "OK" volume setting most of the time, instead of ideal, unless you get lucky.

Further, and related, I found the remote volume control almost completely useless because of the hyper-sensitivity of the volume control. Maybe constant practice would help, but I gave up after two evenings of frustration.

As I alluded to above, to facilitate optimum grounding in different homes and systems, a grounding/floating switch would be helpful.

Conclusion

"The Truth" changes the paradigm in Reference Line Stages, literally. Its existence has even forced me to remove a "Direct Connection" in "Class A", because such a choice no longer makes any rational sense to me. In the end, "The Truth" is effectively a "direct connection" with no sonic downsides, and with the ability to drive any amplifier load and/or length of cable, while allowing any source to be heard at its very best. With the exception of extra gain, an audiophile can't ask for more than that. I realize that this may all sound "too good to be true", but it isn't. Maybe more important than even that is this: On the most subjective level, "The Truth" facilitates a direct human connection to the music and/or recording, to a greater degree, than anything else I've heard.

I've had a challenge describing and placing "The Truth" in a larger perspective, while remaining consistent with the previous observations and evaluations within this website. Example: More than 5 years ago, in February 2011, I wrote this about the Coincident Statement Line Stage: (The CSLS) "is the most 'perfect' electronic audio amplifying device, of any type, that I have ever heard" (italics added). This review raises an obvious question: Has "The Truth" now invalidated that 2011 statement? The short and definitive answer: No.

My 2011 CSLS statement is still valid even today, because I deliberately included the specific qualifier of "amplifying". To be clear, the CSLS is still the finest amplifying device that I'm aware of, in any category. However, I must emphasize that my description and evaluation of "The Truth" is even less qualified than the CSLS:

"The Truth" is the most 'perfect' electronic audio device, of any type, that I have ever heard, and that is why I also describe it as "one of a kind".

"The Truth" line stage epitomizes true "High-Fidelity". I wish J. Gordon Holt had lived long enough to hear (and see) this design. "The Truth" brings back the feelings I had in the 1970's, when prices weren't outrageous, even for the highest quality components, and you still believed that someone just starting out, and completely unknown, could "build a better mouse trap" by offering a component as good or better than even the most famous and expensive models, even if it looked "cheap", and still sell it at a price that virtually any hobbyist could afford. (The direct selling price of "The Truth" is $ 975*.)

The Bottom Line- If the source provides a satisfying volume level (verify this with "The Bolero Test"), and the "garage built" appearance is not a problem (see below), then "The Truth" is the most desirable line stage I know of at this time, and at any price.

*This is the price for the basic model. Extra inputs and outputs will cost more, as will the remote volume control option. Check the website, link below, for further details.

An Addendum on "Consistency"

I feel it is important and necessary to discuss this review of "The Truth, in detail, in the context of consistency (or what I've written in the past). Consistency, continuity and perspective are almost always missing in modern audio journalism. There is a reason for their absence. They are inconvenient and limiting, and thus the mortal enemies of undeserved hype.

To be specific: In my 2011 CSLS review, I wrote that I didn't think it was possible for any line stage in the future to "significantly" improve on the performance of the CSLS. (I later made this exact same claim for the EMIA in its 2012 review, and for the exact same reasons. However, for the sake of clarity, I will only focus on the earlier CSLS review.)

My confidence in making this CSLS claim was mainly based on one factor; the "sonic gap" between a "direct connection" and the CSLS (or the EMIA) was "minor". A minor sonic gap obviously left no "room" for a "significant" improvement, but now the performance of "The Truth" appears to contradict my 2011 opinion and prediction, and this has troubled me. How could I have been so wrong, or was I? So I gave this question some serious thought and analysis, and this is what I believe has happened.

First: The sonic gap between my 2011-system direct connection and the CSLS would still be "minor" today. In fact, the gap would be even smaller now, due to the CSLS' improvements since 2011 (better volume transformers and tubes). Second: The CSLS "sonic gap" consists of two elements, which are equally important. One element is the CSLS of course, while the second element is My Audio System. It is this second element, my audio system, that provides the explanation and answers we are looking for. The details:

My audio system has changed considerably since 2011, and this has an enormous impact on this issue. In fact, every component has either been replaced or modified except the speakers, so I have almost a new system in 2016.

The Most Important System Changes Since 2011:

1. ZYX UNIverse II cartridge replaced "Original" UNIverse*

2. Graham Phantom Supreme tonearm replaced II*

3. Improved DIY tonearm cable*

4. Lenco Reference II and III Upgrades*

5. Jadis JP-80 CuTF capacitor replacements*

6. Coincident Shotgun Interconnects replaced DIY from JP-80 to CSLS*

7. APL NWO-Master replaced Krell SACD Standard II*

8. Frankenstein (.01 uf) CuTF capacitor replacement and superior tubes**

9. Dragon II replaced original Dragon**

10. Coincident Statement power cords (entire system)* & **

Explanation:

*These improvements, individually and cumulatively, have significantly increased the total amount of musical information coming from either the Jadis JP-80 or the digital source. This, in turn, has significantly increased the overall size of the direct connection "sonic gap" between the sources and the CSLS. Further, and just as important...

**These improvements in amplification since 2011 have also made any existing sonic gap, then or now, much more easily noticeable, as well as exposing other sonic problems that existed back then.

In effect, the system deficiencies that existed in 2011, in both the sources and in the amplification, masked some sonic problems with both the 2011 "direct connection" and the 2011 CSLS. While this was unavoidable, I also had no idea in 2011 that the sonic gap could expand from "minor" to "significant" as my system continually improved over the last 5 years. If I made any error of judgment, that was it. "The Larger Lesson"- The audio world never stands still, so serious audiophiles must always remain flexible enough to recognize, and take advantage of, any new realities.

In the end, my improved 2016 audio system is much better able to expose this current sonic gap and any other sonic problems that were previously hidden in 2011. Finally, and inevitably, this expanded 2016 sonic gap created an "opening" for a component such as "The Truth" to fill, which it did.

Relevant Links and Websites:

The Horn Shoppe (Home of "The Truth" Line Stage, plus high-efficiency speakers)

THE BOLERO TEST (Safely answers what type of Line Stage you can use)

My Audio System

2011 Review of the Coincident Statement Line Stage (CSLS)

My Audio Philosophy

Coincident Speaker Technology (High-efficiency speakers, tube electronics and cables)

EMIA (Transformer based components)

LightSpeed Attenuator (A unique passive attenuator using LEDs. Australian. Sells direct.)

Tortuga Audio (Light based passive line stages. Sells direct.)

"The Truth" Line Stage

Below is a picture of "The Truth" line stage currently in my system, with the 10 lb weight on top of it and a metapolymer plate below it. The selector switch is on the left hand side. The balance control is in the center. It is almost at 3 o'clock (instead of 12) because it hasn't been re-centered since it left the factory. The knob on the right is the volume control positioned at around 12 o'clock. The maximum limit of the volume control is around 1 o'clock, while the 10 o'clock position is virtually silent, so the entire volume range is only around 3 hours (see above). The small opening in the center is the sensor for the remote volume control.

P1000796

Important Note- The Review of "The Truth" Line Stage (above) now supercedes the results of any earlier reviews, such as those below.

The Best Passive Line Stage we've heard...

EMIA VOLUME CONTROL

I've finally heard a serious transformer-based passive line stage (volume control) in my system, and it's everything I imagined, and discussed previously, in my lengthy review/essay of the Coincident Statement Line Stage (which I highly advise reading for perspective). The EMIA is now the finest passive preamplifier I've ever heard, and at any price. It is noticeably superior to any resistor-based volume pot I've heard.

Its performance is somewhere in between a direct connection (to the amplifier) and what I hear with the Coincident. It is slightly more immediate, direct ("naked") and transparent than the Coincident, though still not equal to the direct connection (which requires "perfection" and is probably impossible to achieve). However, the amount of degradation is amazingly small, and nothing else I've heard gives you a greater sense of nothing being there (short of a direct connection of course).

The EMIA, while quite simple in design and appearance, has other features that may be important to some. It has two main mono volume controls, plus two more (three-way) switches for fine volume adjustments. I never felt the need to go in between these volume levels. It also has two inputs and two outputs. The (noiseless) sliding input selector switch, for me, became the default "mute switch" (otherwise I would have had to turn down the volume controls every time I switched records). The second output allows bi-amping, which was also important to me, since my system sounds its best bi-amped. However, that brings me to the next important point...

I soon discovered, once again, that my primary source, the Jadis JP-80 Phono Stage, does not have the required energy to drive two power amplifiers simultaneously, no matter how benign their load(s). The EMIA sounded superb with a single amplifier, as I describe above, but the lower bass lost control when both amplifiers were used (which also occurs when I play the JP-80 direct).

This problem was NOT the fault of the EMIA, but instead the inevitable result of the Jadis attempting to do something simply beyond its capability (and basic design). Another source, analog or digital, may not have the same problem. The only method I've found to successfully allow the Jadis to work, (using a passive) with two amplifiers, is with the Cotter Noise Filter Buffer also in the signal path, which I don't want to use at this time. Accordingly, I will still use the Coincident Statement in my own system (which also provides the extra gain I sometimes require and even some sonic advantages over a direct connection - see the review).

As for the particulars, the EMIA Volume Control has a MSRP of $ 1,800 (street $ 1,500), which makes it $ 4,000 less than the active Coincident. According to the manufacturer, Dave Slagle, it is usually in stock, with a maximum lead time of 30 days. There is also a silver version, of "limited availability", that costs an extra $ 1,000 (which I would obviously like to hear one day). I had 1,200 hours of break-in before I made my auditions.

In Conclusion

As I've discussed for decades now, in person and on my website; When deciding whether or not to use a passive line stage, everything depends on whether the actual source has the required energy to drive the actual amplifier(s). In most cases, it does NOT. However, there are still many cases where it DOES (and only an actual experiment* will definitively provide the correct answer). If a system can accommodate a passive line stage, than I don't know anything that can equal the EMIA Volume Control, let alone surpass it.

Further, it's so close in performance to a direct connection (as is the Coincident Statement), I believe it's highly unlikely that anything can ever be substantially superior. Why? There is almost no "room" left for any improvement. Maybe the silver version of the EMIA is slightly superior to the (copper) version I heard. Maybe there are other models out there that are also slightly superior, and maybe there are even models which have the same basic performance and sell for less money, but I am not aware of any of them at this time.

The EMIA actually exists now, "sounds" magnificent, and can not be substantially improved upon. It is my top passive Reference for now and will remain so until the day that one of my various "maybe" speculations becomes an actual reality.

*I devised THE BOLERO TEST more than 20 years ago now, which will assist interested readers to safely conduct this experiment. I believe every audiophile should know the results of this important test, for better or worse.

Relevant Websites:

EMIA

Intact Audio (Dave Slagle)

The Best Active Line Stage with Gain we've heard...

COINCIDENT STATEMENT LINE STAGE

The Coincident Statement Line Stage (CSLS) is the finest component of its type that I have ever heard. Much more than that, it is the most "perfect" electronic audio amplifying device, of any type, that I have ever heard. Further, based on my experiences, which are shared below, I believe that the CSLS can never, and will never, be significantly improved on in the future, no matter what the price or the technology used. I realize that these are unusually strong words, but I believe I can, and will, back them up.

Note- The lengthy essay/review of this line stage can be found in the dedicated Coincident Statement Line Stage File.

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CLASS B

PASS LABS ALEPH L

I was a dealer of this line for a few years in the middle 1990's. This was their most impressive component, by far. While I felt the Aleph amps were good, though very overrated by the audio press, this preamplifier was totally ignored by these same 'reporters'. Too bad, because this was a highly innovative design, beautifully executed and just might still be the most desirable line stage ever made for most systems. The entire Aleph line was discontinued in 2000.

The most original feature of this preamplifier, never duplicated or imitated by anyone else, including Pass Labs themselves, is its automatic Passive/Active signal routing. If the audio system doesn't need more gain than the signal source provides, the Pass will not further amplify the signal. This is achieved by a unique volume control.

The volume control operates passively up until 3:00, and after that it is active. The change between passive, and active, is automatic. Most of the time the volume control will operate below 3:00, which means the Aleph L is, in effect, a high-quality passive preamp, which will always outperform any active design if there isn't an impedance/sensitivity mismatch. Above 3:00, the Pass automatically becomes active. It then slightly dries out the sound, while also adding a thin veil. That's excellent performance, but not outstanding, for an active preamplifier.

At exactly 3:00, in another innovative design feature, the preamp even removes the volume control itself from the signal path, making it as pure and simple as technically possible, with the single exception of a direct connection. The end result is a preamplifier that will compare with the finest passive units ever made, while still offering up to 10 dB of high quality gain if still required.

The Pass has 4 inputs, two ouputs, a single volume control, a selector switch, is on all the time and is built like a proverbial tank. I used it for a number of years (1996-2001) with outstanding results in my retail store. It was superior to every line stage of every preamplifier I heard during that period. It's a perfect marriage of true high performance and practicality. I understand they are now going used for less than $ 1,000. That makes it an incredible bargain.

Caveat- The earliest version of the Aleph L did NOT have the active/passive automatical volume control which makes the later version unique and special. The early models are NOT References. The Aleph L is also not for those who want maximum "convenience". It does not have a remote control.

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CLASS C

I will be adding some components within this class as soon as I confer with my associates.

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THE BOLERO TEST

Introduction

More than 20 years ago, around Spring 1992, I had a dilemma. I had recently purchased the Expressive Technology SU-1 Transformer and was finally able to use a low-output moving coil (Monster Alpha Two) cartridge with my Jadis JP-80 preamplifier. The initial problem was that, when using the Expressive transformer, I now had too much gain, even with the Alpha Two. (The Jadis' stepped resistor volume control couldn't be adjusted precisely at below 9 o'clock.)

So I decided that maybe the line stage of the Jadis could be removed. That would reduce the gain and (hopefully) also improve the sound as a bonus. However, I didn't want to electrically remove the line stage first, which was a lot of trouble and work, and then find out that I didn't have enough gain without it, or had other unforseen problems. So I would have to play a record first, without going through the line stage, to find out.

How is that done?
Simple; the signal going to the amplifiers would now come from the "tape outputs" and not the usual "main outputs". However...

There is one BIG problem with this approach; you can no longer adjust the volume, since the signal, now coming from the tape outputs, will bypass the volume controls along with the line stage. This means that if the signal is too strong, which is a distinct possibility, it may damage your amplifiers, speakers and even your hearing etc. After some thought, I realized that I had to find a record with music which could inform me, with plenty of time for reflection, whether or not I had:

1. Sufficient gain, plus
2. No compromise in the quality of sound and,
3. Still not pose any threat to my system (or myself).

The near perfect solution:

Maurice Ravel's "Bolero"

Bolero starts off extremely softly, which is perfect for safety, but it also slowly builds up and ends with a sustained crescendo, with the entire process taking more than 10 minutes. That is plenty of time to decide if the gain of the system is adequate or not. There are also a large variety of instruments to listen to, which also makes Bolero an excellent test of the quality of the system when not using an active line stage.

The Technique

This is the step-by-step process to test the system, using Bolero, with the minimum amount of risk.

Preliminary Steps

1. Find and play Bolero on your system in a normal manner, meaning with the main outputs and at your typical listening volume. Remember the volume, exact volume control setting and the sonics carefully. The exact position of the beginning of the Bolero cut on the record must also be remembered.

2. Find the softest volume-level record in your collection, which will be the LP which requires the highest volume control setting to sound "right". Then play it at the exact same volume control setting previously used for "Bolero". Remember this sound level.

Practical Steps

3. The amplifiers must then be shut down until the I.C. cables going to them can be removed without danger. The preamplifier can and must remain "ON".

4. Then reconnect the amplifiers to the tape output of the preamplifier. Don't turn the amplifiers back on yet.

5. The preamplifier's selector switch should be on the source that is just "one click" away from phono, so that the phono input can be switched in (and out) with one quick movement. This other source will now become the de facto "mute" position. The preamplifier must NOT be on the Phono input when the stylus is placed either on or off the record. The new "mute" position will now be used on these occasions.

6. Make absolutely certain that the source selected as "the mute" has no signal going through it. (A signal can cause serious damage.)

7. Now the amplifiers can be turned back on and warmed up. Important- If there are any "strange noises", then immediately shut the amplifier off, and then check the connections and/or sources. Remember, the volume control is now totally useless at this point.

8. After the amplifiers are warmed up, put Bolero back on the turntable and cue the stylus. When the stylus is "secure" within the groove, then (and only then) switch the selector control to "Phono". You will now be hearing the record without the line stage. (You may also hear a "pop" when making the switch, if your selector control has a grounding problem.)

9. Now you must listen carefully until you know exactly what is happening. Here are some typical scenarios:

A. You may notice either immediately, or after a while, that the volume is too soft compared to your normal listening level. If so: That's it! It's Over! There is no use going forward. Your phono stage does not have enough gain to drive the (relatively) insensitive amplifiers and/or speakers. This audio system, as presently constituted, requires an active line stage with gain, and there's nothing more to say or do.

B. You observe that the system is louder by a large (easily noticeable) degree, than your usual listening level. The next step is to listen for the quality of the sound (before Bolero gets too loud). You will want to know if anything is "lost"; such as dynamic expansion, deep bass, body, impact etc. If nothing is "lost", consider yourself very fortunate, for you can now go on to the next stage, removing the line stage entirely, or bypassing it, with confidence. For quick verification, you should also play the LP used in "Step 2", which has an ultra-low volume level, while always remembering to use the "mute" while doing so.

C. If the volume is around the same as the "reference", or just a little bit louder, you must realize that this will be the maximum volume level after the line stage is removed (with the current system). You will have to now decide whether or not you can live with this upper volume level. Once again, you must also listen to the quality of the sound. Further...

If "C" describes your situation, you should then play other records (making sure to always use the selector control as a "mute" first), to verify your impression of the results. You should particularly choose records that were cut with a lower volume, so as to discover the potential "bad news" immediately. This is where "Step 2" becomes critically important, because this "softest LP" alone may be the one and final experiment which decides the ultimate result and decision.

In my own experience back then, the output without the line stage was still quite excessive, so I removed the line stage the next day and I had incredible results. The sonic improvements were staggering to me, and I didn't use a line stage again for almost two decades.

CD PLAYERS?

The same test can also be used with CD players (without volume controls) using Bolero. Once again, you connect the CD player directly to the amplifiers (using the same caution) and put on Bolero. You can also still go through the preamplifier's tape outputs. You don't need a "mute" input with a CD player, just use the stop button. Then wait for the results. Just make absolutely certain it is Bolero, or the same potential dangers, described above, will apply.

CAVEAT

If you don't fully understand the entire procedure, or it just seems too difficult or risky, then do not attempt this test. This test is meant for veteran audiophiles. I will not be responsible for any problems, of any nature, caused by its use, or more likely, misuse.

I have used this test personally, or on other people's systems, around a dozen times, so I know that it works, but only if properly executed. In the past, I always explained it, face-to-face, to experienced audiophiles, who understood the procedure. I can't control who will read the above steps, but it's definitely not for "beginners", or anyone else who isn't certain what they are doing.

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Some (Initial) Thoughts on Other Interesting Line Stages

Channel Islands Audio PA-1 Passive/Active Preamplifier- A reader sent me this good news about a possible successor to the Aleph L discussed above. Here it is (edited):

"I wanted to mention that the Pass Labs Aleph L has been imitated, contrary to what your article says... it has been imitated by Dusty Vawther of Channel Islands Audio/Monolithic Sound here: http://www.ciaudio.com/"

Personal Note- It is called the "PA-1 Passive/Active Preamplifier", and it retails for $ 599, compared to $ 2,000 for the Aleph L when it was new. While the basic design is the same, and even the basic appearance is similar, the active circuit is probably different, as well as the power supply, transistors, passive parts etc. So the sound, at least in active mode, will also be somewhat different, but this is still a model that anyone, at any price point, should look into. It's the most logical method of amplifying a line signal. Maybe they'll even come out with an "all-out" model one day, although they already offer an updated power supply (HC-1b, $ 279).
Bonus- There's even a "30 day/no risk trial", so you can find out if the preamp works in your system without a monetary risk.

BAT VK-3i LINE STAGE- A reader, who has sent this site a considerable amount of information about the MFA Luminescence, has recently tried using the "Lumi" as a dedicated phono stage, and the BAT VK-3i as a line stage. Here are his (edited) observations:

"(I) had a chance to live with a BAT VK-3i line stage. Surprise-surprise: it has general tonal balance of a Lumi (not an easy task as it uses 6922 tubes) but outperforms it in every respect. It is clearer, more resolving, more dynamic and very palpable. It is no surprise that these sell like hotcakes on the used market ($800 plain, $1000 with remote, it was $2K new). It has Jensen paper in oil 1 mF output couplers, which are extremely transparent, but which roll off the bass slightly (-3 db at 20 hz, -0.5 db at 63 hz, but can be easily fixed by replacing with 3 mF). BAT offers a capacitor replacement, but instead of giving you just one 3 mF cap, they put 6 X 0.5 mF caps in parallel - smart thinking but expensive.

I used the Lumi's phono stage to drive the BAT and it sounded great. Lumi's downfall is actually it's line stage. Before I stick it in the closet I want to try oil caps in it and see if it improves anything. I tried all expensive caps in it and now run Hovlands, but I'll try Infinis today. Doubt they will make a difference. BAT's high frequency resolution is excellent. I find it much more "real" sounding that all the Audio Research gear, Audible Illusions etc. BAT also makes a solid state phono board for it (so-so) and a separate multi-tube phono stage* ($ 2K) which takes most MCs with no step-up. I heard it in my friend's house and it was good. I'm getting it soon for an evaluation. I also heard the Classe Six Mk II. Excellent preamp for the money (with MM/MC phono) - can be had for less that $1K, but it's flat, no dimension."

*BAT Phono Stage- In another letter, this same reader has some further observations about the BAT phono stage he promised above to evaluate in his home. Here they are, with some minor editing:

"After prolonged listening, the BAT (phono stage) proved to be ultimately fatiguing. And, though excelling on acoustical stuff, the BAT can not realistically portray big band or rock or complex classical. The Lumi is never fatiguing, albeit much less exciting and really good with big demanding stuff. So (the Lumi) stays for now. "

Personal Note- I also feel that the strength of the MFA Luminescence is its phono stage. Its line stage is still very good, especially in reproducing body and tone, though it is slow, rolled-off and lacks immediacy. This lucky reader appears to have found the "best of both worlds", and without spending "big money".

More Recently After reading the above comments on the BAT VK-3i line stage, another reader had some of his own observations to share, while also introducing a new model from this same manufacturer. I felt his (edited) experiences were relevant and important:

"I have read in the ("Recent File") of one of your reader/associates experiences with the BAT VK-3i preamplifier. I owned one of these for 2 years, 1998-2000. At the time I thought it was quite good. And in fact, I think this unit has been the best selling unit that BAT has produced. When Victor redid his preamps in 1999, he kept the 3i in the lineup because they were his best selling product at that time.

I replaced the 3i in August 2000 with a newer preamp from BAT, the VK30SE. This preamp was a real step up from the 3i in tonal quality and soundstage presentation. The 30SE was much smoother, (as) the 3i in comparison was rather solid state sounding, and the 30SE had a much larger sounstage presentation than the 3i, which was much smaller. This VK30SE was the preamp in my system until I made my little passive unit."

Further observations from this reader- The same reader had some experiences with a home built passive line stage he also shared:

"...I have finally taken your advice and dispensed with the preamp in my audio system. I designed (although there's not really much designing involved) and constructed a passive pre with a shunt stepped attenuator. I do have a selector switch for inputs, but have the main input direct to the attenuator. This made one of the largest fundamental differences in listening that I have heard!!!! Musical details heretofore unheard were suddenly all THERE. I was so stunned that I reconfigured the system with preamp back in just to be sure I was not mistaken. And sure enough, with the preamp in the system, the details disappeared. Out went the preamp to collect dust, and eventually on to another owner. Total cost for my little gem was somewhere in the neighborhood of $200-250. I used Elma switches and Vampire OFC connectors and wire. I used a Vishay S102 resistor for the shunt resistor. And according to Guy Hammel, the Placette guy, one really needs Vishay S102's in a passive controller for best results.

All (is) well and good with the preamp, but I do not listen to records or pop/rock type musics, so therefore my comments on the passive controller are a bit limited. But certainly for one who only listens to classical musics with a digital input player, a preamp just covers up the details. And details are what classical music is all about. The change with the passive controller is so dramatic, that even discs from Deutche Grammophone now sound quite detailed and complete. And I must add that with the passive pre I did NOT suffer any of the loses, bass and dymanics, often noted with passive units. I hear all the music just as it was recorded." (9/04)

Personal Notes- This reader heard the benefits of using a passive preamp because his system did not have an impedance mismatch between the source and his amplifier, which would normally require an active preamp to overcome (along with the sonic price of the active). In my own system, I've used both Vishay and (the much less expensive) Holco resistors. At this time the cheaper Holcos work even better for me, but both are recommended in the inevitable attempt to optimize the system.

CONRAD JOHNSON ART LINE STAGE- One of my associates heard the CJ ART line stage and was very impressed with it. He told me that it was the finest and most neutral component he's ever heard from Conrad Johnson. He also preferred it to the Audio Research Reference line stage, which he felt was both lean and a little dry. From my perspective above, I recommend avoiding active line stages, but if I didn't, the ART would be near or at the top of those we've actually heard.

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READERS LETTERS

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READERS LETTERS

CAVEAT-Please be advised that the readers’ letters posted on this site are solely the opinion of that reader and may not necessarily represent or reflect the opinions of Arthur Salvatore or High-End Audio. These letters furthermore, are not to be taken as being endorsed by Arthur Salvatore or High-End Audio. They are posted because they may be edifying, thought provoking or entertaining.

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MUSIC FIRST PASSIVE MAGNETIC PREAMPLIFIER- A reader sent me a letter stating that he was "surprised" that I still hadn't mentioned this in my "Other Interesting Line Stages" file. He's right, I should have mentioned it. This model, along with the Bent Audio version (below), is the best solution to those who want a passive preamplifier, but have an impedance mismatch with their source and power amplifier(s). This will solve that problem, and can even give you a few db of gain.

They achieve the impedance matching by the use of high-quality transformers. The resistor passive is still potentially the least harmful to the signal, but it only works in a small minority of systems (such as mine).

BENT AUDIO TAP PASSIVE PREAMPLIFIER Basically the same performance as the above. This isn't strange because they both use the same exact transformer. Both models are nice looking and well built. This model is put together in Canada, while the Music First is made in England.

A Reader's Letter from September 2006

"Update to Line Stage page: http://www.high-endaudio.com/RC-linestages.html

One of best-engineered passive line stage offerings was the "Mod Squad Deluxe Line Drive AGT" designed by Steve McCormack. This can be found used for just a few hundred dollars. A later model, the McCormack Micro Line Drive, was also v. good. It had 3 inputs, a tape monitor and both a passive and active output.

The current, in-production successor to these products is the McCormack Audio RLD-1. It goes for $ 1,700 new, has a remote and is available with an optional MM/MC phono stage.

Here's Steve's thoughts on his passive designs:
http://www.hometheaterhifi.com/volume_2_1/passive.html" (9/06)

Personal Note- I, and one of my associates, also had some positive experiences with the McCormack passive and active line stages. They are also reasonably priced, especially when found used at a discount.

An Interesting Letter from Thorsten Loesch

Here's part of a letter from Thorsten Loesch, who's made several valuable contributions to this website over the years. Thorsten takes issue with my prior statement of the comparative weaknesses of the two types of passive preamplifiers; those with resistor-based volume controls (which are also my preference) and their transformer-based equivalents. There's some minor editing, and my bold:

"There is a DIY unit (DIY HiFisupply Django as option) and several commercial units (Music First Audio PMP [also with silver wound transformers!], Bent Audio/Music First TAP Audio Sector T-Pre, AVTAC Pasiphae) that all use the Stevens & Billington TX-102 Attenuator Transformer.

This transformer, and the TX-103 Step-up you found so good, are both developents from Stevens & Billington's TX-101 Studio Line Transformer, and where initiated and specified by me (also with quite a bit of design input), and developed to the current form by Jonathan Billington of S&B, with input by Bent Audio's John Chapman and myself. In many ways the performance of the TX-102, a simple "line" transformer, is the same as the TX-103 used as stepup.

I would like to also take some issue with your statement: 'The resistor passive is still potentially the least harmful to the signal, but it only works in a small minority of systems (such as mine).'.

During the initial development of the 102, many comparisons where made to "true ladder" attenuators, which had only two Vishay Resistors as voltage divider per position. In fact, the attenuators in question included the Audio Synthesis "Passion" passive preamplifier, which uses a single fixed Vishay resistor in the series position, and switches only the shunt resistor.

Martin Colloms, in his technical review of the MFA PMP in HiFi News, also compared the PMP (copper) to his Audio Synthesis Passion, and found the MFA PMP notably superior. To mention that HiFi News selected the £ 1,500 MFA PMP as "Product of the Year" two years running, with the runners-up being the £ 5,000 active designs by Conrad Johnson and Musical Fidelity's best last year (not sure about who the runners-up where this year), is redundant, except for noting that no-one was bribed or any other kickbacks given.

So no, the resistor is still, and remains, the more harmful solution to attenuating the signal, when compared to a truly high quality attenuator transformer. That this fact has gone mostly unnoticed is simply down to the fact that Music First Audio and Stevens & Billington (as well as Bent Audio) concentrate on making exceptional products, NOT on marketing, getting loads of positive reviews and pump tons of money into advertising. You should try a transformer based passive preamp one of these days, you may find that it gives a lot better SSS (Shared Sense of Space) than resistors..."

My Response to Thorsten (and my Readers)

I still have an open mind on this subject, but I think everyone should know why I originally wrote that resistors were less harmful to the signal than transformers. (And please remember that I emphasized that they "only work in a small minority of systems...")

1. Two (or even more) of my readers have had the Bent TX-102 in their systems, or its English equivalent, and informed* me that they preferred their passive volume controls, which they felt were "less noticeable". That's why I haven't already approached John Chapman of Bent Audio about borrowing one of them. I realize this contradicts the observations of Martin Colloms, but I don't give Mr. Colloms any more credibility than I do my readers, despite his experience.

*Their letters would be routinely posted now, but back then (2003/4) I rarely posted reader's letters.

2. Then there's my experience with moving-coil transformers and resistors in the signal path of my own system. This is A/B/C logic, so you will all have to bear with me. I have continually had resistors in and out of the signal path on the output of my preamplifier (phono stage) for years now. (I don't like the Vishays too much, even though they have this big reputation, along with their price. I actually prefer the much cheaper Holco.) Every resistor I have tried has noticeably degraded the signal to some extent.

However, I felt the signal degradation of any of these resistors (one resistor in series with the signal) was noticeably less than the degradation of the copper Bent Moving Coil transformer compared to its exact silver equivalent. Now, even if the silver MC is considered "perfect", for the sake of argument, this is still proof to me that the copper transformer degrades the signal more than a resistor, unless it's "apples and oranges" comparing a line transformer to a MC transformer. If Thorsten has an explanation for this, I would like to hear it, and post it.

Right now, I don't use even one resistor in the signal path, so the Bent, or the MFA, is useless to me. (I play my system at full volume on every LP because of the low output.) This may well change in the next few months, so I'm prepared to take the necessary steps to optimize this new reality. For the sake of clarity...

My phono signal path goes from the 2uf V-Cap Teflon output capacitor, with a 10M load, directly to the selector switch, where it then goes both directly to the output RCA female and also the volume control, where the only variable is the resistance value to ground- from 0 ohms up to 250K ohms. I effectively use the selector switch as a "mute", never touching the volume controls, after the first LP, up until the very end, when I place the volume back to "0" for further protection.

Finally, I invite any readers with actual experience on this issue (or "controversy") to send me their observations, which I will post. I promise to protect your privacy as always, and I only ask for complete sincerity in return. (12/06)

ELECTRONIC VISIONARY SYSTEMS "ULTIMATE ATTENUATORS"- These are high quality volume controls (or shunt attenuators*) which attach directly to the amplifier's input (RCA Female or XLR). They eliminate the need for line stages, either active or passive, assuming of course that the source can directly drive the amplifier (a big assumption). This is the way to go if you have ONE SOURCE. A link is provided below and in The Links File.

*A "shunt attenuator" has only one (or no) fixed resistor in the signal path, and only the resistor value to ground ever changes. This is the least harmful method to change volume, in theory. In fact, this is the exact technique (with no fixed resistor) I use in my own system. However, there is a potential risk, because the system's ultimate frequency response may change (for the worse) if it can't handle the varying impedances, which can be too low at times. (12/06)

Passive Magnetic Preamplifiers

Below are two letters I combined from a reader who has made previous contributions to this website. There's some editing, plus my bold:

"I have had a Django Classic passive-magnetic preamp (http://www.diyhifisupply.com/diyhs_django.htm), which is very similar to the Music First Passive preamp, and is based on S&B TX-102 transformer. Maybe my experience with this type of passive preamp is peculiar, but I have had a lot of components mismatch with it, and I have tried it with many components in many systems. I have sold it because I was tired to continually search for a good component synergy.

So my point is that these passive-magnetic preamps may not work easily in everybody's system, and may not be the best solution either for a passive preamp. However, there is of course the possibility that all this is related to my own unit. I did not try other passive-magnetic preamps.

(Second Letter)

I have used the Django not only in my system, but also in many others, so with many different components (different sources, different amps, different speakers (but always high-efficient ones)).

So I made the comment not only based on my experience in my system, but also based on my experience in other systems. Sometimes it works (and even that it is not perfect), but the vast majority of times it was so-so or awful. Maybe the critical point is having different sonic priorities than Mr. Loesch - or at least it is an hypothesis."

Personal Notes- This is an example of one more letter from a reader who has had negative experiences with a transformer based passive preamplifier, which I mentioned in a December reply. This is from my reply to this reader:

"I still prefer using a resistor based volume control myself, but I recommended the transformer for those who can not use regular volume controls, so I agree with your observations and advice. I'm glad you sent your letter, because my contributor, Thorsten Loesch, still feels that transformers are always the best method for passives, and I believe he is wrong."

I don't know how anyone can reconcile the observations and perspective of this reader and Thorsten, along with the Martin Colloms review in Hi-Fi News, let alone their "Product of the Year" award. (Unless the Django is a complete piece of junk, which doesn't appear very likely to me.) The only reasonable solution I can recommend is a thorough trial before purchase, which shouldn't take that long. I feel the same way about resistor based passives. With all the variables involved, some of them unknown, there's potential for both great success and disastrous failure. (1/07)

Another Passive Line Stage Success Story

This letter is from a reader who had the courage and trust to remove the active line stage in his system, using the "test" I describe in the line stage file. There's only some slight editing, and my bold as usual:

"I sent you an email several months ago regarding my positive experiences with the Bolero test (using a Rotel CDP, Vandersteen 2ce Signature speakers and a McCormack DNA 0.5 amp). So, I just thought I'd give you an update on my experimentation. Since writing to you last, I have purchased a Promitheus Transformer Volume Control from promitheusaudio.com (link below), a very small company in Malaysia. I purchased one of the reference versions at a price of $420 plus shippping, which seemed to be a reasonable price for my experiment. The TVC replaced a Rotel 1062 integrated amp.

I guess it should come as no surprise that the TVC has resulted in a huge improvement in sound vs. using the Rotel as an integrated. I loved the sound when I ran the Bolero test with my CDP and amp, and I'd have to say that what I'm getting from the TVC is very similar if not better. I'm not one to throw around words like "decay" and "speed," etc., when describing stereo sound (I'm simply not fluent in audophile speak), but I can describe the results as follows:

1. Improved bass using the TVC over the integrated. Deeper.
2. The sound is extremely natural. I won't say that it sounds as if the orchestra is right there in front of me; I don't think my Vandersteens are capable of that. But the tinniness I had been experiencing is gone.
3. The TVC is especially impressive with solo voice and single instruments (I mostly listen to piano). But listening to the Karajan CD of Parsifal the other day, I was impressed with the realism and depth of sound of the orchestra, especially during the second half of Act 1.

Of course, I have limited stereo experience. The Rotel integrated is the only thing I can compare the TVC to, other than my experience with attending concerts. The TVC has moved me closer to that experience. Clean sound, improved bass and realistic separation seem to be the major attributes of the TVC. Oh, and voices are more forward (in front of the orchestra), too. As for volume, as anticipated, no problems. The volume control has 24 steps, and I usually play music at six or seven clicks.

The Promitheus TVC, by the way, is a simple wood box with stainless steel tops and bottoms. Inside are the transformers and a network of wires.

Maybe I'm imagining that the sound is less electric (because my brain knows that there's no electric running through the TVC). But I did an A/B the TVC with the Rotel on an unknowing wife the other day, and she picked right every time. I've since sold the Rotel integrated and will probably sit tight with my system for a while (unless a good deal on a Vandersteen 2wq subwoofer comes along)."

Going (Preamplifier) "Passive"

Another reader has experienced a highly successful result when he eliminated the line-stage (and more) of his (excellent) preamplifier. I love these letters, because more than anything I could ever write, they may help to encourage other audiophiles to experiment for themselves. There's nothing to lose, and so much to gain (for free!), if the remaining components are compatible. There's only minor editing, and my bold as usual:

"...Your efforts to articulate sound reproduction concepts are generally not well understood by most audiophiles. I refer to your thoughts on "sound-floor" and "low level information".

I have been seriously listening to some kind of high-end audio since about 1975. Due to budget constraints, I have not spend a lot of time with very high priced equipment and most of my listening has been done with modified vintage tube electronics. The modifications included replacing capacitors with the best I could afford. Over the years, I have owned the Conrad Johnson MV-75, the Dyna PAS, a Linn, a Well Tempered Table, many cartridges, Maggies, and a variety of home made speakers. Of course, the results have varied widely, depending on the equipment, the quality of parts I could afford, and the inherent design limitations. I was rarely satisfied, however the sound was usually better than what I heard in the local high end salons.

In your writing, you describe the improvements that you hear when you reduced the number of parts in the signal path, between the source and loudspeaker. Your writing on eliminating line stages is a great example, and I recently put your ideas to good effect in my system.

I have an Atma-sphere MP-3 preamp. After listening using the both the phono stage and the line stage, I decide to try the phonostage connected to my power amps through a passive preamp, that consisted of a 10K Caddock resistor and a 250K pot to ground, to adjust the volume for each channel. This combination had enough gain to give me loud enough music, and the increase in low level detail was very noticeable. Everything was better, the bass, the soundstage illusion, everything. After reading more on your website, I decided to eliminate the 10K Caddock resistor. Wow, another amazing improvement. I had no idea how obviously colored that resistor was.

I then began to think about the pieces of wire, and the switches, that remained in the signal path in the phono section of the MP-3. It seemed logical that those extra parts had to be effecting the signal. I opened the preamp and connected short lengths of wire directly to the output of the phono board. I ran those wires to a phono jack that I mounted on a bracket inside the preamp. Mounted on the bracket, with the jack, is a 100K pot to ground (no resistance in series), to adjust the volume. The result was a much simpler signal path.

This is the cat's meow! The phono stage sounds great wired this way. Until I heard my LP's through this setup, I had no idea how much very delicate musical detail in all frequency ranges was being retrieved by the cartridge. Before this modification, all that information coming from the cartridge was being masked by the extra wire, contacts and the line stage itself. By the time it reached my loudspeakers, it was gone.

My system consists of a modified Thorens turntable and arm, with a cheap Grado cartridge, the Atma-sphere Phonostage. The passive volume control signal goes to two stereo amps. One is a modified Eico push pull EL-84 amp, driving some dipole ribbons from 300hz up, and the other half of the signal goes to an equalizer, and an electronic crossover, driving dipole woofers (ala Linkwitz), with a modified Harmon Kardon Citation II. Not even close to state of the art, but with the line stage eliminated, the sound is amazing."

Personal Notes- This reader has basically duplicated what I did with my own Jadis preamplifier. The only difference is that I use a 250K pot. Sadly, I recently had a similar highly positive experience when I removed a 50K Vishay resistor from the signal path. Maybe Thorsten Loesch was right after all about the inferiority of resistors compared to transformers.

Prometheus TVC Update

Here is a short write-up of the new, all-out, Prometheus Transformer Based Passive Line Stage. The two letters, which are combined below, are from a veteran reader. There's very little editing and my bold:

"My Signature TVC preamps from Prometheus Audio have arrived a couple of days ago. Unfortunately, my bottom copper plates are bent, which Nicholas suspects is a form of shipping damage, so I cannot mount them on the included ebony cones. Even as they are, they sound incredible. At $1,600 I think they are very good value by YOUR measure. The are dual mono/dual box to minimze crosstalk and maximize channel separation. Large custom double c-core transfomers, elna switches, etc. Prometheus is serious about this product.

My system is currently in an interim state. Still the Scoutmaster/JMW-9/Empire MC5/Wright Sound WPP200C phono front end, and an unmodded (for now) MHZS CD88E digital front end. Speakers are DIY crossoverless Audio Nirvana full rangers at around 97 db/w/m in room. All cables are Speltz solid core Anti-Cables. Amp is the better integrated Sonic Impact II T-Amp, until Prometheus develops its Signature transformer coupled 300B SET amp.

Adding the Signature TVC (and an extra set of interconnects) has been the single largest improvement to my system. The extra detail is obvious across the spectrum. The tonal accuracy appears to be excellent, and the decrease in homogenization is probably at least significant, so that individual instruments are better spatially and sonically isolated. Imaging is better too. For the first time ever I now have sound that I now consider 'high end', and I wouldn't be embarassed to have an experienced audiophile listen to it even if I'm still short of Class A territory.

The best example of what I've heard in these first few days is a CD I have of older Louis Armstrong. The benefits of the TVC are very apparent when he sings scat. Whereas before I couldn't really understand what he was signing, it is now quite intelligble, remarkably so.

The older TCV model from Prometheus were found to require 400-450 hours to fully break in. Nicholas Chua, the man behind Prometheus, feels his larger double c-core Signatures will take noticeably longer, but I've yet to see any figures. Based upon the improvement noted in these older models, I should be in store for noticeable improvements. But they sound excellent right out of the box. Perhaps Thorsten (Loesch) was right as you've wondered.

One note about Prometheus. They are victims of their own success, so they are sometimes a little slow to respond to emails and don't always make their expected shipping dates. But as others have mentioned online, I've found Nicholas to be honest and trustworthy, and with this level of performance and value I can live with a little frustration.

For an entry level system, getting one of the basic Promiteus TVC models used on Audiogon and mating this to a T-amp of some variety and a pair of DIY Audio Nirvana high efficiency, full range/crossoverless speakers is certainly one of the most cost efficient approaches to developing an economical yet revealling system. I dare say you would be surprised what this combination, which is likely less than $1,200.00 and only requires sources and cable, will do.

As for me, who has been more a Class C/buy used type of person, the $1,600 Signature TVCs are far and away the best component and value I've ever purchased. These will go to my grave with me.

In my haste to reply, I neglected to add two important observations about the Prometheus TVCs, both positive. Firstly, they have a very articulate sound, which my wife criticized as being 'too sharp' (i.e. Lifelike). The 'shape' of the notes is very distinct, and I think this is into the arena of outer detail if I understand the term. There is no sonic blurring of the notes. Whatever it is, it adds a significant element of realism to the music. Secondly, I noted a significant improvement in decay, which caught my attention on piano pieces especially. The resonant properties of the piano notes is quite attention-grabbing, and the prolonged decay of the notes again has a very realistic portrayal.

I likely won't have time to do a detailed assessment of the Signatures for a while, as they will have to be returned to Prometheus for repair. But they are an excellent component and certainly worth your attention." (2/08)

ARIA WV11XL Line Stage

I have no experience with this model, and neither do any of my associates. However, a veteran, experienced and helpful reader sent me his detailed observations. The reader's first language is not English, so I did my best, within reasonable time constraints, to help with the grammar. Here it is, and the bold is mine:

"I would like to post some listening impressions about my new preamp that I purchased last year. It's the long-awaited unit from ARIA, a new brand owned by Mike Elliott, (ex-Counterpoint designer) very well known for many outstanding preamps in the 1980's. My choice was the WV11XL, a tube line stage only (but there is also available a full unit with MC phono, costing only $1,000 USD more), so my report refers to the line stage and not the phono (I do have an external SA-9jr unit from Counterpoint).

The unit has now reached approximately the full burn-in process required by the manufacturer (200 hours), and the sound is more cohesive and sweet. Please refer to the manufacturer's website for the complete specifications. All the listening sessions were made testing alternatively both the RCA and XLR connections. The remote is a cheap piece controlling the volume knob only. The construction is excellent and the finishing looks equal to the best competitors.

I have made some listening sessions in comparison with a few excellent preamps (see below), both tube and solid-state, using three different power amps:
BAT VK-55 first version;
EAR 509 monos;
Counterpoint-AltaVista NP220 (premium plus level)
,
These power amps have three different sounds, with EAR's apparently more vivid and dynamic, but much less refined. The BAT has a nice tonal balance (the best of the three), but it has limited power in the bass region when it's pushed hard. The speakers are my Kharma CE.2.3, with ceramic drivers for midrange and tweeter only. In this contest, the hybrid tube-SS NP220 is preferable, with more depth in the soundstage, and better definition and beauty on voices. It's also the most powerful of the three, with better control in the bass.

Preamps I had in my room for a comparison in the last year were the: ARC REF 1, Spectral DMC-20; Mark Levinson ML-26 and ML-320; BAT VK-51SE; LAMM LL2 Line Stage.

I understand that these are not the current flagships for each brand, but all of them are highly regarded preamps with very very good tonal balance, detail and flexibility. Some of these were better concerning the not important feature of the control range in the volume pot (steps of 0.5 db for BAT). The Spectral, as expected, more thin and one sweet spot; Lamm a little bit dark in tonal balance, ARC and ML-320 with a nice sound in all spectrums. The overall sound quality of the Aria WV11XL is just in another class; better on every parameter, sometimes with a little margin, sometimes with a large difference. You hear immediately a more lifelike presentation of the music. You have great and superior resolution of low-level details, both of the musicians playing and also the small ambience noises are clearly much more audible than the other preamps, and contribute to create a more lively performance.

The SPL variations of program music seems effortless, but at the same time musicians and singers remains in their place on the stage; superb depth and great sense of air. Music appears more cohesive. To my ears there's not a part of the frequency spectrum that is better than another; high frequencies are obviously extended, clear and not compressed, but never never fatiguing. You receive the involvement in listening that sometimes you obtain through different tubes designs that do their best in midrange resolution, but here, with the Aria, you have more speed.

It's not as fast as the Spectral (most preamps and power amps from Spectral are the fastest on the market), but at the same time you have IMHO a correct decay of the music, not slightly truncated as I have listened with some SS preamps. This is easy to hear, not only with solo performers (Oistrakh's violin on Bruch Scottish Decca 6035 seems now in perfect tonal balance), but especially when the music becomes complex, as in the most part with great symphonies, with many musicians.

For each comparison, I waited until the solid-state units remained turned on for at least one day before judging; but with other preamps in every match the general sensation is of nice detail and timbre, but less vivid sound; you play good music, you have detail but... you are two steps back. Please note that the comparisons have been made detaching for a few minutes all systems before start again. Units for comparison remained in my home from 3 days up to 2 weeks for listening.

Vinyl and CD were used alternatively; all kinds of music, with 50% classical (both symphonic and small scale); and the rest of jazz group and pop. I know very well the character of some of the greatly loved labels, like old Mercury's, RCA, Decca, etc. I do have a large selection of vinyl rated in your Supreme Recordings, so some of the discs of that list were used for listening.

The design circuit of the ARIA is unusual; a small switch allows the use of both 6 and 12 volt tubes; so... you can enjoy tube-rolling. Each change caused different gain, and also the tonal balance and soundstage will vary. I know only one other preamp that has a similar feature; it's the Italian Lector model Zoe (but this latter has less tubes). I'll try it in my home soon.

Actually the Aria comes with good new EH ECC88; until today my preference goes to old Tung-Sol 12BH7A black plate, but I have not tried yet all the long list of compatible tubes. I had a further little improvement with some rolling in two (of the four) tubes in the power supply section.

I gave attention to the choice of power amp input impedance. My EAR 509 were modified raising a value of 100K ohm; BAT given from a friend of mine is 215K ohm and NP220 is approx. 500K ohm. This last is a perfect match for a tube preamp that has a declared output impedance of 2-3000 ohms approx. I had the opportunity to try the huge and well reputed VITUS 101 SS power amp, but I refused, since the input impedance value is a prohibitive 600 ohms in balanced mode (a value that seems typical in professional market). It is impossible for Aria to drive it without losing high frequencies and dynamics.

My opinion is that the ARIA WV can probably easily compete with the best products on the market. I'm thinking of the most famous tube competitors, like ARC REF5, or the BAT REX. Sure it's possible that some other little brand may do better in some aspects, just for example, I read something enthusiastic about new Joule Electra 450 Marianne Electra, as well the Audion Premier Quattro and Jadis JP-80* you quoted on your site. Also, here in Europe, we have a few small brands with great reputations for their best preamps. Since I made any comparison side-to-side, I can only suppose that the WV11XL from Mr. Elliott will be in the same league.

About price, I can't make any consideration, since a brand that has the direct sales service only should be clearly cheaper than competitors that sell through dealers, I don't want to analyze this problem, for now." (12/09)

*Personal Notes- The Jadis JP-80 is a "Reference" on this website only for its phono stage. I have bypassed the internal line stage completely (in 1992). Consequently, I have no idea how it would compare to other line stages, even if heavily modified.

I'm also not surprised by this reader's observations of the Aria, since I, and other serious audiophiles, felt Counterpoint (Michael Elliott) produced better components than Audio Research or CJ (and others), when they were in business, in both absolute terms and "for the money".

This is what I wrote about this important subject a few years back, but still feel is relevant...

An Active Line Stage

Do you really need one?

It happened again. Another concerned reader wants me to hear the latest ("best") active line stage in my own system. He's positive that it will make an improvement, since I'm "only" using (in effect) a passive preamplifier (my Jadis JP-80 preamplifier's selector switch and volume controls- the stock tube line stage having been removed and bypassed 16 years ago).

Here is a small part of what he wrote to me: "I am coming for you. I agree with you 100% that the active preamps from the 80s and 90s are inferior...".

The reader's argument then boils down to this: I avoided using an active line stage all these years only because their performance was relatively poor compared to my passive line stage, but once I hear an "outstanding" model, I will go back to an active.

This was and is not true.

More importantly, the actual performance of an active line stage is not even relevant to whether it is needed in a system or not. Since other readers may also be confused about this critical issue, and because it appears that I haven't done a good enough job with "The Bolero Test" to help audiophiles understand and answer the line stage question), I will try again, but this time from another angle:

The Active Test and The Rule

This test is very simple. If you are currently connecting a phono stage or a CD player directly to an amplifier, or through a passive device (and then to the amplifier), simply add any decent active line stage, or replace the passive device with any decent active device (it doesn't have to be "the best"). Once this is done, then listen to the results. The Rule...

If there is any noticeable and obvious sonic improvement with the active line stage, then you need an active line stage. It's that easy. All that's left is the most difficult part, choosing the model that you like the most.

What this reader (and many other audiophiles) doesn't understand is that the quality of the active line stage is not critical when it comes to making the determination of whether you need an active device or not. What is critical is whether the source (CD player and/or phono stage) has the required output to drive the amplifier directly (beyond simple volume needs). It either does or it doesn't. This is black and white.

Most sources do not have the required output. When they don't, it's extremely easy to expose their sonic weakness(es). In fact, virtually any active line stage (short of total "junk") will sound better in some noticeable manner (deep bass, dynamic intensity, more natural "body" etc). (It will also sound worse in some manner, but that is irrelevant at this point.)

Alternatively, when the source does have the "required output" (which is my present situation), then no active line stage, no matter how good it is, will prove to be superior in any noticeable manner. In fact, it will rarely even equal the sonics of the direct connection in any manner (because of all the extra cabling, connections and an imperfect active circuit). Even a theoretically "perfect" active line stage can only equal an equivalent passive line stage with the required output, because they both must share the same passive parts (volume control, selector switch, wiring etc).

In the case of my own system, once I realized, through actual listening experiences, that no active line stage of the day (early 1990's) could improve on what I was hearing, in any manner, than I knew that no future active line stage could alter that fundamental paradigm, no matter how good it was. This was because my source had the required output. The best I could ever hope for in an active line stage would be something that sounded very similar to what I had, but with more gain. The quality of the sound could never be improved on. If it could, I would have heard some improvement 16 years ago.

The above "test and rule" is based on multiple experiences, not only in my system, but in many other systems I am/was familiar with. It is NOT some speculative "theory" I've put together for some irrational or egotistical reason, and I've never heard any exception to this "rule". So...

In short, if you need an active line stage because your source is not up to the task of driving the amplifier(s), then...

Any good active line stage, from any era, will improve the sonics in some obvious and clear manner.

Alternatively, if your source is up to the task of driving your amp(s), then...

No active line stage, no matter how good it is, will ever equal the sonics of your direct connection (or an equivalent passive).

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