REFERENCE COMPONENTS-LINESTAGES

Any system that sounds better with the addition of an "Active" Linestage is an unequivocal indication that:

A mistake has been made in the choice and "the matching" of the components and/or cables.

However, there is no need to worry or panic if you have, or require, one at present. The vast majority of audio systems require an active linestage. The elimination of the active linestage is a long-term goal that requires each and every component to be optimized and matched with regards to both sensitivity and impedance (and cables for low capacitance).

This means that most systems, at most times, will require an active linestage.

Finally, never forget that all active linestages are actually "passive" linestages along with (active) amplification. In short- you can't avoid using a passive linestage in any circumstances (unless you want no volume controls). The only issue/choice/decision, in this instance, is whether you want an active stage in addition to the passive.

Always keep in mind that preamplifiers came into existence to equalize and amplify the very low-level phono signals from a turntable. Most tuners and tape decks had their own volume controls, and didn't need a preamplifier when used on their own. Also, many power amplifiers had their own volume control. After CD players became popular, and turntables became relatively rare, preamplifiers became (theoretically) "obsolete" and/or "redundant".

However, rather than lose the sale of a (now) obsolete component, the manufacturers began marketing a "new" component, the "line-stage" (which is just a preamplifier without a phono stage).

They could have placed the line-stage directly within the CD players themselves, which would have been more convenient, economical and even have saved the cost of an extra pair of cables (a sonic benefit too). They predictably didn't. Why? Profits.

Where were the "underground audio magazines" (who were supposed to be looking out for the interests of their readers) while this "transition" was all happening? They were giving "rave reviews" to these (now) expensive and unnecessary components.

This technique will always be the most optimum and least compromised method of transmitting the signal, both in theory and in practice, BUT it is very difficult to achieve.

For a phono system, this means that the phono stage must be directly connected to the amplifier(s). Eliminating the line stage in a system with a turntable/phono signal source is more difficult and also more musically rewarding than with a non-phono system. I know this from more than 15 years of first-hand experience with my own system.

The main problem to overcome is that many phono stages, especially those with tube amplification, have both a relatively low-level signal and a high output impedance. This is an awful combination which makes it very difficult for them to directly drive the power amplifier(s).

In a CD system (or tape, tuner etc.), the analog* outputs must be directly connected to the amplifier(s). There is a much greater chance for this scenario to succeed compared to a phono system. The fact that it still fails, in many (if not most) cases, is because the analog stage of the CD player (or DAC) is not properly designed.

In many instances, this "failure of design" is done on purpose. The reason is to force the owner to purchase a separate linestage, hopefully from the exact same manufacturer of the ill-designed CD player or DAC. ("Sir, don't overlook brand name compatibility!")

* Digital volume control can not be used in this test. They adversely effect the amount of musical information leaving the source.

There should always be at least an attempt to connect a single source directly to the power amplifier if possible; using a CD player or DAC’s (or phono stage's) analog volume control etc., even if the volume pot has to be installed. (See The Bolero Test just below for sources (and amplifiers) without volume controls.

Even more ideal is a volume control at the input of the power amplifier. This would eliminate the need for the volume control within the source to also drive an interconnect. If there is more than one source and there is no selector-control, then you must audition a high quality passive line stage (see below).

Also important are the interconnects, which must have low capacitance in this instance, or the frequency extremes may be noticeably rolled off. Making sure these cables are as short as possible may even make the difference between success or failure.

NOTE- There obviously must be a volume control either within the phono stage, at the CD analog output or at the amplifier input for a direct connection to be even functional.

If the system has more than one source, a passive linestage (meaning there are no transistors or tubes in the signal path) will almost always be required. It is not quite as "pure"* as a direct connection, but it is more practical for most audiophiles.

*The compromise is essentially the necessary addition of an extra interconnect cable in the signal path.

Fortunately, passive line stages can be easily built by non-technicians. More and more kits are available using high-quality volume pots, selector switches, RCA females etc. Even paying someone to build one should be economical, since the parts can be purchased directly.

If any active (preamplifier) line stage sounds better (in any manner) than the passive, than there is at least one impedance and/or sensitivity mismatch (mistake).

Important- Accept in rare instances, the use of a passive linestage will not overcome any compatibility problems that already existed when directly connecting the source to the amplifier. It simply adds multiple-source flexibility, that's it.

Further details on this topic will be in another section (under consideration) focusing on putting a Minimalist system together.

More than 15 years ago, 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, with the Expressive transformer, I 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 linestage 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 physically remove the linestage 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 linestage, 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't adjust the volume since the signal, now coming from the tape outputs, will bypass the volume controls along with the linestage. This means that if the signal is too strong, which is a distinct possibility, it can damage your amplifiers, speakers, 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,
2. No compromise in the quality of sound and
3. Still not pose any threat to my system (or myself).

Bolero starts off extremely softly, perfect for safety, but 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. There are also a variety of instruments to listen to, making this an excellent test of the quality of the system without a linestage.

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

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 and the sonics carefully. The exact position of the beginning of the Bolero cut on the record must also be remembered.

2. 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.

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

4. 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.

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

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

7. 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 linestage. (You may also hear a "pop" when making the switch, if your selector control has a problem.)

8. 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. That's it. There is no use going forward. Your phono stage doesn't have enough gain to drive the (relatively) insensitive amplifiers and/or speakers. This system, as presently constituted, requires an active linestage, 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"; like dynamic expansion, deep bass, body, impact etc. If not, you can go to the next stage, removing the linestage entirely, or bypassing it, with confidence.

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

In this instance, you can also play other records, making sure to always use the selector control as a "mute" first, to verify your impression of the results. You should choose records that were cut with a lower volume to discover the potential "bad news" immediately.

In my own experience, the output without the linestage was still quite excessive, so I removed the linestage the next day and I had incredible results. The sonic improvements were staggering to me, and I have never used a linestage since then (though I have tried a number of them).

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.

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.

It happened again. Another concerned reader wants me to hear the latest ("best") active linestage 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 linestage 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 linestage all these years only because their performance was relatively poor compared to my passive linestage, but once I hear an "outstanding" model, I will go back to an active.

More importantly, the actual performance of an active linestage 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 linestage question), I will try again, but this time from another angle:

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 linestage, 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 linestage, then you need an active linestage. 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 linestage 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 linestage (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 linestage, 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 linestage can only equal an equivalent passive linestage 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 linestage of the day (early 1990's) could improve on what I was hearing, in any manner, than I knew that no future active linestage 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 linestage 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 linestage because your source is not up to the task of driving the amplifier(s), then...

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

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

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 linestage 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.

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

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 LINESTAGE- One of my associates heard the CJ ART linestage 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 linestages, but if I didn't, the ART would be near or at the top of those we've actually heard.

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.

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.

One of best-engineered passive linestage 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.

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

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..."

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)

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.

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)

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 LineStage 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)."

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 affect 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.

Here is a short write-up of the new, all-out, Prometheus Transformer Based Passive Linestage. 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)

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 linestage 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 linestage.

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".