PART ONE- MY PERSONAL LINE STAGE HISTORY & PERSPECTIVE
PART TWO- THE JADIS JP-80 ERA (1989 TO 2011)
PART THREE- THE BYPASS TEST
PART FOUR- THE COINCIDENT STATEMENT LINE STAGE BYPASS TEST (RESULTS)
PART FIVE- INTERPRETING THE RESULTS OF THE BYPASS TEST
PART SIX- WHY IS A LINE STAGE USUALLY SUPERIOR TO A DIRECT CONNECTION?
PART SEVEN- WHY DOES THE SOURCE USUALLY FAIL TO FULLY DRIVE THE LOAD?
PART EIGHT- WHERE WE STAND NOW
PART NINE- CONCLUSION AND MY ADVICE
PART TEN- WHAT I AM DOING AND WHY I AM DOING IT
PART ELEVEN- AUDIO SYSTEM AND SOFTWARE USED FOR THE EVALUATIONS
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.
First of all, any veteran reader of this website is aware that I do not "like" and, much more importantly, need a line stage. This is why I was very reluctant to audition and review the CSLS, or any other line stage in existence for that matter. Other audio websites (Stereo Mojo and Enjoy the Music) had already given the CSLS "raves" and "awards", but that meant nothing to me, due to my somewhat unique circumstances. However, I eventually agreed to review the CSLS (and the matching phono stage), and I finally found the time to start experimenting with it in Fall 2010.
I initially thought it would be simple and fast, like my prior evaluations of other line stages, both active and passive, but this was not the case. This time it was different, and it has taken me a considerable amount of time to figure things out, mainly in an effort to logically connect and match my (and others) personal observations and experiences with the different technologies which created them.
In fact, the entire line stage situation is surprisingly complicated. Let me explain...
I have been experimenting with line stages, and/or their absence, for three decades now. It began in early 1981, when, it is important to remember, line stages, per se, didn't even exist as individual components. They were just one part of a full-function preamplifier, which always included a phono stage as well.
A few months before I opened my audio store, I found myself with the (Mitch) Cotter Phono Stage and the matching Cotter MC Transformer, along with the Audio Research D-150 power amplifier (then stock), along with the original Quad ESL-57 speakers (modified), the Linn Sondek LP-12 turntable and a Denon 103S cartridge (tonearm now forgotten). Despite my best efforts (and even my own brother working for Cotter), I was not able to get the matching Cotter line stage (which was, and is, extremely rare). So, I used the line stages of some high quality full-function preamplifiers (which had their own phono stages), such as the Citation 11, Dynaco PAT-5, Dayton-Wright SPS and ARC SP-3.
Then, one day, realizing that the D-150 had its own volume control, I decided to bypass the line stage I was using at the time, and instead connected the Cotter Phono Stage directly into the ARC amplifier. It was a bit of a pain, since the single stereo volume pot was at the back of the amplifier. Still, I felt the results were well worth it. It turned out that the sound was obviously improved; it was purer, cleaner, faster, more direct and immediate etc. However, due to the relative insensitivity of the Quads, the volume was just too low for too many records, making it impractical, but the seed had been planted. So I committed myself to eventually making a direct connection work, and without any sonic compromises.
After that, there were numerous similar experiments in the 1980's*, in both my store and personal system, but I feel they are redundant, and would like to now focus on my personal situation with the Jadis JP-80 preamplifier, which I purchased in 1989, and I still own today. The JP-80 has been at the center of every experience I've had, with both phono stages and line stages, since then.
*PS Audio designed a preamplifier (PS IV), which I demonstrated and sold in my store, that allowed the user to bypass the line stage with the push of a button.Top
I first used the Jadis primarily with high-output MC cartridges (it has no MC stage, as does their current "MC" version), until I purchased the Expressive Technology SU-1 MC transformer. Literally overnight, I went from too little gain to having excessive gain, even with low-output MC cartridges. The problem was that the volume pot, using individual resistors, didn't allow fine adjustments below 10 o'clock, and I was usually at 9 o'clock or below, so the music was almost always too loud or too soft. This was obviously highly frustrating.
Thinking things over, I decided to attempt turning my gain problem into a plus by removing the line stage, but this strategy created another problem. How was I going to find out if I could successfully bypass the line stage, without the major hassle of actually bypassing it internally first, and without any guarantee that it would work?
Of course, I could simply use the tape output instead, which bypassed the line stage, but that created yet another problem; the tape outputs also bypassed the volume controls. This meant there would be full volume at all times, which placed both my then amplifiers (Jadis JA-80) and then speakers (Wilson WATTS modified) in serious jeopardy. (The JA-80 did not have its own volume control, as did the Audio Research D-150 in my earlier experiment.)
This dilemma was the inspiration for the creation of The Bolero Test, which solved the problem, and has also helped many other audiophiles since then. In short, the test was highly successful, so I bypassed the JP-80's line stage in 1992. (Over the years since then, I also eventually removed the tape monitor, the mute circuit, the cathode follower section and, finally, the two mono volume controls, which turned the selector switch, in effect, into the "mute switch".)
The (modified) JP-80 preamplifier had now been converted, basically, into a "phono stage". Subsequent experiments, with various dedicated line stages, confirmed that none of them were able to make an improvement in the sonics when inserted into my system. These results were verified by numerous listeners, and not just myself, because I recognized my "animus" towards line stages, which had began a decade earlier (1981). I wanted no prejudices to cloud my observations.
This has been my system's status quo from 1992 until now (though I've made many further improvements to the JP-80 over the years, in both the circuit and the power supply). Then the CSLS arrived...
The CSLS is a two-chassis unit, weighing 74 lbs in total (the power supply alone weighs 41 lbs). The (hard-wired) signal path is a combination of transformers* and one tube (101D), which I've never seen in any other audio amplification device. There are both RCA and Balanced inputs and outputs. Critically important, there are no capacitors or resistors in the direct signal path. It has 20 dB of gain. (For more details and pictures, you can visit the Coincident website.)
I initially broke-in the CSLS with 300 hours of play (using an SACD player), though I now believe that it takes a few hundred extra hours before the CSLS sounds its very best. This is definitely longer than average, and I believe it is caused by the transformers in the signal path.
*The late Harvey Rosenberg is the first person I know of that wrote about this theoretical design approach. Sadly, he did not live to hear its (highly successful) implementation.
As of today, the JP-80 is using only two tubes, both 12AX7. The other four signal path tubes in the stock JP-80 (all 3 in the line stage and the phono stage cathode follower) have been removed. There is one V-Cap Teflon capacitor coupling the two tubes and another (larger) version at the output of the second tube. The RIAA equalization is accomplished with feedback, using Stanley Lipschitz's formula. All the power supply capacitors are film. Only the selector switch is still in the direct signal path, with every other switch bypassed. The volume control, which is resistor based, is now only a shunt to ground, so it is not in the direct signal path. In fact, there are no resistors in the entire direct signal path. This is critical to remember, if the reader's goal is to fully understand and appreciate this review/essay.
So the complete JP-80 direct signal path is now this: RCA inputs - 12AX7 - V-Cap Teflon - 12AX7 - V-Cap Teflon - Selector Switch - RCA outputs.
I am not able to make the signal even purer than the current JP-80, short of removing the selector switch, but that would leave me without a (quick) mute. This is impractical and very dangerous, if not reckless, when using a phono source. Also, experienced readers will now realize that, based on the current signal path, I have only two options when it comes to the volume level; full volume or nothing. That's the trade-off for this degree of minimalism, purity and unprecedented sonics. (It is also an advantage when evaluating passive components, such as resistors and capacitors, and especially line stages, both passive and active, such as the CSLS.)
However, I also created a third option, which I've been using, on and off, for the last decade: I utilized a second input on the (5 position) selector switch for the phono output, but this time I put a (high-quality) resistor in series with the signal. This option will reduce the volume level by a fixed amount. The selector switch then, depending on the position, provides me three choices:
1. A direct, full-volume output, with no resistor, or
2. A "Mute", or
3. An output that is slightly attenuated, because the signal goes through one (high-quality) resistor.
This discussion of the signal paths, selector switches and resistors may all seem like excessive and irrelevant detail, but it is just the opposite. The ultimate performance of the CSLS, for better or worse, is all in relation to, comparative with, and dependent on the performance of the JP-80 itself. This is because we are not going to compare the CSLS to just another line stage (as in every other serious review), but, instead, to the source itself ("perfection").
In other words, we are going to make the ultimate comparison; A Bypass Test.Top
There is no tougher, and more revealing, test than a bypass test. This is because the "standard" or "ideal" is not the listener's "taste", or a memory, or an alternative component in a normal A/B comparison, which would have its own strengths and weaknesses. This time the standard is "the source", which can be considered effectively "perfect", even though, in reality, it is not. Of course, the better the source, the easier it is to hear it being degraded. However, in the final analysis, the source takes the place of "perfection", because any audible deviation from the source, by the component being tested, is a deviation, in effect, from "perfection". In other words, the closer the component comes to mimicking the source, the fewer flaws it has, and the closer it is to "perfection". The inverse of that maxim is also true. It is as simple as that.
Unfortunately, only one actual component, the line stage, is capable of a "bypass" test, because it can be successfully bypassed in a system. The same is true with some signal cables, but nothing else in the signal path (amps, speakers, cartridges etc) can be bypassed, only compared, which can never be as revealing and/or effective. It can be very difficult to arrange a bypass test, but that is no excuse to ignore them. If you never seem them mentioned, let alone performed, in the mainstream magazines, there is a good reason for this. Bypass test are TOO definitive because of their objective and revealing nature. There will be real and unavoidable sonic problems that are exposed, as well as "winners and losers", and the magazines, these days, only want to declare winners, and certainly not dwell on component deficiencies.
Now, to remove any potential confusion, I want to make clear what I mean by a "bypass test", with an easy to understand example, and then I'll discuss the CSLS bypass in particular. Imagine a six foot speaker cable is under consideration. The question: How close does it comes to "perfection"? (Which I define as "no cable", or a direct connection of the amps with the speakers.) This is a difficult, but not impossible, test to accomplish. (In fact, one of my associates has already made this exact same test in his own system, and then later successfully eliminated the speaker cable in the process.)
First, the mono amplifier is placed directly behind the (electrostatic) speaker, with only a few inches separating their respective binding posts. The speaker is then opened up. The speaker's (six inch) internal cable (attached to its binding posts) is now unattached. Instead, this same internal cable is directly connected to the amplifier's binding posts. Thus, there is now a direct connection of the amplifier and speakers, and without the need of any external cabling. (If the amplifier's own internal cable is long enough, it can also be used to connect to the speaker's binding posts. So there are two potential methods of accomplishing this type of direct connection.)
When the system is then next played, the performance, for better or worse, becomes "the standard". It doesn't matter that it is not "perfect". For our testing purposes it is "perfection", because any sonic change we observe, when we later actually connect and use the six foot speaker cable under test, is a deviation from "the standard" (regardless of whether it is liked or disliked).
Finally, when it comes to conducting a line stage bypass test (in contrast to a cable), there is one critical assumption we must make; That the source, whether it is a phono stage, a CD/SACD player, a DAC or just a tuner, has the full capability, on its own, to successfully drive the input stage of the amplifier, and the connecting signal cable, without any sonic compromise(s).
And this brings us to the CSLS bypass test itself...Top
"The Source" consisted of the JP-80 connected to the Coincident Frankenstein M300B amplifier(s) with a six foot length of (prototype) interconnect cable. I used a 1 meter Coincident Extreme Interconnect cable (CEI) to connect the Jadis to the CSLS, and the same prototype cable to connect the CSLS to the Frankenstein amp. So, both the CSLS and the CEI were added to the signal path. Accordingly, any and all deviations originated from the combination of the component and the cable.
An attempt will be later made to separate the respective sonic "culpability" of the two "additions", but the major point here is this: Never forget the fact that when adding a line stage to a system, the system will also be adding an extra cable along with it.
The Deviations of the CSLS and CEI combined:
1. A touch of "immediacy" and "gut presence" and "nakedness" is lost
2. There is a tiny bit of "rounding" on sharp transients
3. Images are slightly "laid back", around 4 to 6 inches
4. A touch of "air" is lost
Where "The Standard" and the CSLS/CEI combination sounded basically indistinguishable (to me):
1. Bass; extension, impact, control, detail etc.
2. Dynamic contrasts, shifts and intensity, at all volume levels
3. Soundstage size, focus, separation etc.
4. High frequencies
6. Everything else, not mentioned above or below, that I've (temporarily) overlooked
Where the CSLS/CEI sounded superior to "The Standard"*:
1. A touch more natural harmonics
2. A tiny bit purer (mainly at high volumes)
3. Bodies of instruments (and singers) slightly more realistic and solid, and less "fun house mirror"
4. Sound is somewhat more effortless, as if the amplifiers have more power
Before discussing the above in detail, it must be emphasized that all the changes, for better or worse, are quite subtle, meaning an average person, with no interest in audio, would probably not hear them. However, any experienced audiophile should be able to observe all of the above. In fact, three friends actually did hear the above differences (and similarities) in my system.
*This means that "The Standard" was not capable of fully driving the connecting cable and the input stage of the amplifier, despite my incorrect assumption that it had this capability. However, I can and will defend myself below.Top
There is a lot to digest from these results, and with many important implications that can't be avoided and will be discussed, but I would like to first focus on the deficiencies of the CSLS, since that will usually be the primary focus of most audiophiles:
It should be no surprise that, since no component is figuratively perfect, the CSLS has some audible deviations (or deficiencies), but what is truly important is both what they are, and their minimal degree of audibility. What is surprising is that the deficiencies are limited only to those areas that are always compromised when there is extra cabling added, which is exactly what happened in this instance (the CEI and the CSLS signal path transformers). It's almost like the actual CSLS amplifying tube had no deleterious effect at all, or at least none observable by us (so far).
Actually, after some contemplation, I believe that I've heard similar deficiencies (in kind and in degree) when simply going from a 1 meter cable to a 3 or 4 meter cable of the same type. Accordingly, I'm amazed that these problems are all that I can report on the downside, but I believe I can do even more to accurately describe the degree of the deficiencies. This is where all the prior discussion above, specifically about resistors, will now become highly relevant.
Readers will recall that there was an option on my Jadis JP-80 which allowed me to slightly attenuate the output by having the signal go through one resistor (which was then connected to one of the inputs of the selector switch). So this resistor was in series with the signal. The value of the resistor, which changed depending on the system requirements, was usually 20K or 50K. The resistor manufacturer and series was the: Vishay VTA. This particular resistor is considered to be one of the finest in the world, meaning it does a minimum amount of audio degradation, and it costs around $ 10 each.
I, along with a number of my friends, have a lot of experience (10 years worth) listening to the effects of this one resistor on the signal, since I only had to move the selector switch two places to make a comparison (Direct - Mute - Vishay 20K). Since no resistor I know of is perfect either, this finally brings us to "the big question": How does the imperfect CSLS compare to the imperfect Vishay VTA resistor?
This is easy to answer: The Vishay resistor's sonic "presence", and its sonic problems, were far easier to hear than the CSLS. The type of deficiencies of both are quite similar, but the amount of those same deficiencies is not similar. The Vishay VTA easily crosses the "threshold of hearing", even when one is not listening for it. This is not the case with the CSLS. I would like to be as specific as I can...
I would estimate, using a numerical scale, that the Vishay is approximately three times easier to notice. In other words, in bottom-line listening results, the CSLS has around 35% (+/-10%) of the Vishay resistor's sonic problems. I can't be more exact than that, since I am not an infallible machine.
However, if personal, anecdotal observations will further help in this instance, I can add this: Whenever I went from "direct" to the Vishay, the degradation was obvious. The reaction was immediate and dramatic, especially from other listeners; "What happened?" etc. You didn't have to listen for the problems (as with the CSLS), because they were literally impossible to ignore, at least for an audiophile. In fact, I have ended up rarely using the resistor option, because "too loud" was still preferable in almost all cases. So, "three times" may even be conservative, but the CSLS degradation is, at the worst, around half that of the Vishay. That is what must be taken away.
I am going into this amount of detail for several reasons; this allows any reader, with Vishay resistors, to repeat my experiment for a total cost of $ 20. It is also a further verification of my observation of how little the CSLS adversely effects the signal, and finally, it quantifies my use of the words "touch" and "tiny", when I initially described the degree of the CSLS's deficiencies.
This brings us to my final word on this important subject:
I made this claim in the first paragraph of this review: "the CSLS can never, and will never, be significantly improved on in the future, no matter what the price or the technology used." If I observed any component, and not just a line stage, deteriorating the signal by only 35% as much as a high quality resistor, how could I believe, and write, anything other than that about that same component?
There's not much to say here, but it's important to note that, in most ways, the CSLS and "the source" are essentially the same. That is significant in this particular case. However, while I, and other listeners, were not able to hear other sonic differences, even when listening for them, it is still possible that I/we may hear some differences in the future. The important point is this: If they are eventually heard, they will be, by definition and in practice, inconsequential. If this were not so, they would have already been heard and described.
There is one other critically important observation to note at this time, which is directly related to why I mistakenly* assumed that "the source" was fully capable of handling the next stage and, consequently, could not be improved upon. Something occurred that was without any precedent in my audio life, both in my personal system or any other system I've ever heard.
(*Further- My preamplifier's output capacitor and volume pot values have both changed in the last decade. Plus the amplifiers and cable length have also changed in the last few years, effecting the load of "the next stage". That's everything!)
To be specific, within "the indistinguishables" there are both "bass" and "dynamics". In all my years of experience using line stages, and removing them, it has always been these two areas which have been the most effected (read "compromised") when a line stage, if necessary, is not in the system. In fact, listening for compromised bass and dynamics is the primary test to discover whether a line stage is a system requirement or not (mainly because any related problems are extremely easy to hear).
And this experience is universal, since one can read literally hundreds of listener posts complaining about "the lack of bass and dynamics" when switching to a passive system, or when using a direct connection. Accordingly, it never dawned on me, because it had never occurred in the past, that the source could retain the bass and dynamics and still be sonically compromised. This means it's possible that a line stage can make a sonic "improvement" even if and when it does not also "improve" the bass and dynamics.
This naturally leads us to the next subject, which required some (speculative) thinking on my part...
We will first briefly discuss the particular "improvements" we observed with the CSLS (already described above), and then we will tackle the larger subject of (line stage) "Improvements"; focusing specifically on how and why they even occur in the first place.
In general, the sound, overall, with the CSLS in the signal path, was a little more "natural" and "realistic". It was certainly not a "significant" change, let alone "dramatic", but it was noticeable. The instruments and singers had a little more natural solidity and harmonics, and the sound was a little cleaner and more effortless. It was almost like the VTA was optimized after being slightly off, along with a little more amplifier power. Nice, but it's not a big deal on its own. However, I believe that it is a "big deal" that any "improvement" was noticeable.
This brings us to the critically important issue which lies at the heart of this review/essay. This subject, which is usually avoided in favor of personal anecdotes or, even worst, completely ignored, must be seriously addressed at this time, even if no answer or understanding can ever be completely satisfying to everyone.Top
This question, or subject, has been in the back of my mind, as some type of unsolvable dilemma, for many years now. Accordingly, I must take this step by step, and start with some basic definitions and descriptions of the relevant fundamentals. Without this basic context, we can go no further.
First of all, when I used the word "improvement" above, it was always with quotes (""). This was not an accident, because a line stage can never literally improve a signal. Such an improvement is figuratively and physically impossible in our world. Require some proof?- If it was actually possible to improve, or enhance, the signal, then two line stages would have to be even better than one, and three even better than two, and so on to infinity (resulting in sound better than "live").
If a literal improvement is then absurd (and illogical), then what do we actually experience when we do hear a line stage "improve" the sound of a system (that was previously without one)? It is certainly a given that we all agree that what we hear is real, and obviously not just our imagination, or wishful thinking.
What a (properly operating) line stage does is to enable* the (existing) signal, from the source, to fully drive both the interconnect cable and the input stage of the amplifier, and without any compromises. By "compromises", I mean that the line stage must overcome all the fundamental (and usually easily observable) problems which are caused by not having a line stage in the system. To be specific, they are: (Problems with) Volume, Bass, Dynamic Energy and Body.
(*Just as an output transformer will enable an amplifier's output tubes to drive the speaker, or a MC transformer will enable a low-output MC phono cartridge to drive a MM phono stage.)
In other words, if the line stage doesn't even enable the source to fully drive the load, then it is a failure (period), and must be removed and replaced. All that should ever matter to the listener, when evaluating a particular line stage, are that line stage's own (unavoidable) deviations (type and degree), which will be observed when the said line stage is used. And, needless to say, the better the system, the easier it will be to hear those deviations (such as the examples I listed above).
So, to answer the above question, the line stage sounds superior to a direct connection because the source, on its own, usually fails to fully drive the load, and thus requires an "enabler" (the line stage). And so we come to the next related question/issue...Top
The answer to this question is straightforward (and self-evident): It can only be because the signal from the source lacks the type and/or amount of energy required to drive the (combined) load.
This then brings us to a discussion of these specific signal source "failures". This requires some speculation on my part, since I don't believe anyone has all the answers as of today. Here are the typical sonic problems, which are directly caused by these failures:
Lack of Proper Volume- Needless to say, any system without enough gain, from the source alone, to reach a satisfying volume, must obviously use a line stage. However, sheer gain (or volume), from the source, is not enough, on its own, to avoid using a line stage! Just as critical is where the gain is located in the signal path...
Example- My (stock) Jadis JP-80, which had both a MM phono and a line stage, had enough gain (volume), on its own, for many MC cartridges, but it sounded absolutely horrible (distorted, compressed, lean etc). Why?- The line stage gain was "too late" to "save" the (delicate MC) signal, which had been already "damaged" trying (in vain) to properly drive the MM stage. This is why the MC transformer, I later purchased, which was designed specifically for ultra-low level MC signals, when combined with only the MM stage, sounded so much better than just the MM and the line stage, even though the total gain was almost exactly the same for both combinations.
This "gain location" (or position) concept must be understood. The total gain of the MC/MM was the same as the MM/LS, but one of them sounded outstanding, while the other sounded horrible. So pure numbers, in this case total gain, are only half the story, and not definitive.
Roll-off of Frequency Extremes- This is very easily heard by most listeners and it's also easily explained, even if you don't have a technical background (and I don't). In most instances, the cause will be an impedance mismatch between the source and the load, so one, or both, frequency extremes will be rolled-off, and sometimes dramatically (most of the bass). There are actual scientific formulas for these impedance induced roll-offs, which are, in effect, filters, though unwanted in this case.
Compressed Dynamic Contrasts- This is also easily heard, even by non-audiophiles. Further, it is critically important to understand that compression is independent of volume, because "loud" does not have a direct correlation with uncompressed dynamic swings, especially those that can startle you with their intensity. The root cause, once again, is that the focused energy of the (source) signal is "lost", or "disbursed", when it attempts to drive the load (by itself). The sonic result of this failure is a bland, "dead" and boring reproduction of the original recording. And simply raising the volume won't bring the music back to life. Dead is dead.
Compromised Harmonic "Relationships"- This is a much more subtle problem to observe, though if it is pronounced, the sound will lack "body", which is relatively easy to hear. What was new (and unexpected) for me was the hitherto unobserved problem with harmonic completeness, which I only noticed after the line stage was installed in the signal path. A serious problem, such as a lack of natural body, can be easily explained by a roll-off, and/or a lack of low frequency energy from the (weak) source, but what about the missing upper harmonics?
My working theory is that when a signal (from the source) is too weak (on its own) to successfully energize the load, the "relationship" of the fundamental frequency, with its related harmonics, will be "shuffled" (like a deck of cards). In effect, mixing diamonds with clubs and spades with hearts. So, while the information may all still be there, the ear won't here it because the relationships have been changed, and it then becomes just "noise" (to ignore), instead of related sound (music). A line stage, if working properly, will avoid all of this.
In effect, the "structural integrity" of the signal is the first thing that goes when the signal from the source lacks the adequate energy for the load. It is not easy to hear, because it is subtle compared to the other sonic problems that usually accompany it during this failure.
Less Purity- This is also a subtle observation, and it's also less common (though I experienced it in my own system). This occurs when the sound of the system is actually cleaner with (then without) a line stage. That observation would appear to be a contradiction, if not impossible, on first reflection, since additions to the signal should always mean additional distortion, not less. However, there is a logical explanation for this: It must mean that the inherent distortion of the line stage is less than the increase in distortion caused by the source (unsuccessfully) trying to directly drive the load of the input stage.
How and why this makes sense- A line stage is a lot like an output transformer in a tube amplifier. The transformer is also an addition to the signal path, but it still reduces distortion (and many other problems). In addition, even if an amplifier has more than enough power for the speaker, distortion will still be noticed if the incoming signal is compromised because it couldn't drive the amp's input stage.Top
Our highly surprising experiences with the Coincident Statement Line Stage (CSLS) have profound and highly unusual, if not contradictory, implications. On one hand, my overall perspective on (the use of) line stages, in general, has not appreciably changed. However, on the other hand, much of the underlying theories, details and real-world practicalities, which are (and must be) the foundation of any serious and rational advice concerning this component, have been forever altered. Let me explain...
I still believe that a direct connection, between the source and the amplifier(s), when usable, is, and always will be, the ideal method to achieve the highest fidelity to that source. However, there is one serious and unavoidable "fly in the ointment" with this method, which must be addressed. Even if a direct connection is possible (without any sonic compromises), and extra gain is not a requirement:
The answer to this critical question lies in the observations within this review...
From my perspective, one of the most important observations, noted in this review, is that a single (high quality) resistor did more harm to the signal than an entire line stage which, critically, did NOT use a resistor based volume pot. Instead, the line stage used an ultra high quality transformer based volume pot. So, the first "rule" is crystal clear:
Avoid all resistor based volume pots*, either in a passive or active line stage (and I would also most certainly include the source itself in that "rule").
*Thorsten Loesch was the first audiophile, I know of, to claim that resistors deteriorated the signal much more than transformers, when discussing volume pots, especially in passive preamplifiers. I was originally skeptical of his claim, but he has been proven to be correct, as I admitted, on this website, years ago.
Next, when specifically evaluating the CSLS itself, I can now state that it is possible to build an active line stage, which is available commercially, that does noticeably less sonic harm than just one (high quality) resistor. This is obviously a "breakthrough" of sorts, at least in my experience, with line stages or any electronic component for that matter. There is nothing, I'm aware of, even approaching the performance of the CSLS at anywhere near its price, and while it may be understandably expensive ($ 5,000) to some, it is also far less costly than many other line stages (while still being far better built).
Further, from my and others experience, even the vast majority of those more expensive models will also not approach the CSLS in performance, despite their (far) higher price. (A single resistor, anywhere in their signal path, will automatically disqualify them.) Ultimately, even if a "perfect" line stage became available (at some unimaginable price), it would only slightly, and insignificantly, outperform the CSLS, based on our (acid and merciless bypass) tests.Top
1. If a line stage is a system requirement, and the CSLS is affordable (even many times over), then I would purchase it, and only it, and without any qualification. Even if it's a "reach", I can guarantee that the CSLS is well worth it. The CSLS is the closest thing to a "straight wire with gain" that I am aware of, and it will never be significantly superseded in pure sonic performance. (If a remote control and/or LED display are "priorities", then this is the wrong website.)
2. If, for budgetary concerns, the purchase of the CSLS is impossible at this time, then I would get the Doge 8 (which also has an excellent phono stage). As far I know, there's nothing else that is remotely close to these two models available today, for both ultimate performance and value (including their build quality). If a reader is prepared to purchase a used component, the Pass Labs Aleph L, discussed in Class B, may be attractive, and it should sell for under $ 1,000 (but they're rare and hard to find).
3. What if an audiophile is certain that they don't need an active line stage? Then I would look for the finest transformer based passive line stage that is affordable. I would avoid all resistor based passive line stages, no matter what their price, reputation or claimed performance. (The Lightspeed Attenuator may be another excellent option, but we have no experience with it.)
4. What if an audiophile still doesn't know yet, for certain, if they need an active line stage, or not? Then I would either use:
A. The Bolero Test, if the system already has a line stage, to discover whether it can be successfully removed from the signal path. Or...
B. Borrow a high quality line stage if the system has never been tested with a similar device in the signal path. The "bottom line" is simple: Every audiophile must be certain of the signal source(s) drive capability, one way or the other.
5. When using any line stage, active or passive, you must be certain that all the sources are playing at full volume. This will then mean that they have no (extra and harmful) resistors in their signal path.Top
I decided to purchase the Coincident Statement Line Stage. This is the first time I've had a line stage in my system since 1992, so this reflected a serious change in system direction and strategy, and not just a routine switch/upgrade of components. This was my reasoning:
The CSLS slightly improved the performance of my system overall, though that subtle improvement, on its own, was not large enough for such an investment and change. However, three further benefits made the decision for me.
1. My system would now have enough gain to play all of my low-cut records at natural volume levels, which was not true without the CSLS.
2. I would also have the ability to play all my records, and digital software, at the most optimum level, which was also not true without the CSLS.
3. I'm now able to directly bi-amplify my speakers without using the Cotter Noise Filter Buffer, which slightly "dried-up" the bass frequencies. (The Cotter was necessary if the Jadis, on its own, had to drive two amplifiers per channel. I used it only for the bass amplifier.)
Explanation- The only method to reduce the volume level, with the Jadis by itself, is to put a (resistor based) volume pot in the direct circuit path, which will adversely effect the performance (as I describe above), unless I use an outboard transformer based volume control. So the three options I had were clear:
1. The status quo- This means having only one volume level (all-out), which is either (somewhat) too low or too high for a good deal of my software. I can only lower the volume by compromising the sonics with a resistor based volume pot. I would also have to accept and live with a slightly lower level in performance (versus using the line stage). Further, I would still have to use the Cotter for bi-amping. Finally, I would have no extra gain for all the software that was too low in volume.
2. An outboard transformer based volume control- This option would allow me to attenuate the signal if it was too high, and without compromising the sonics. However, it offers no gain for all the records and digital software that are too low in volume. Further, the sonic problems (described above), caused by the inability of the Jadis to fully drive the amplifier input stage, would still be noticeable, and I would also still require the Cotter for bi-amping.
3. The CSLS- Which allows me to play all of my music, whether cut too high or too low, and also fully drive the amplifier load, now and in the future, which means the sonics will always be optimum, under all circumstances. Finally, I can even bi-amplify without the Cotter device in the direct signal path.
The Bottom Line- There were too many important and practical advantages for me not to go with the CSLS. My current problems are not only completely solved, here and now, but also in the future, because the unprecedented performance of the CSLS effectively removes any threat of obsolescence from the equation. How often does that ever happen, in audio or virtually any technology serving people?Top
The audio system I used to evaluate the Coincident Statement Line Stage was:
Lenco Reference Turntable
Graham Phantom II Tonearm
ZYX UNIverse Phono Cartridge
Bent Audio Silver MC Transformer
Jadis JP-80 Preamplifier (converted into a dedicated phono stage, and highly modified)
Coincident Statement Line Stage
Coincident Frankenstein 300B SET Amplifiers
Coincident Pure Reference Extremes (Doubled Up)
The records I used the most to evaluate the Coincident Statement Line Stage were:
Bach-Mass in B Minor-Richter-DGG Archive 2710 001 (Voices, Body, Focus, Harmonics, Decays - My Most Played Album)
Dutilleux/Lutoslawski-Cello Concertos-Rostropovitch-EMI ASD 3145 (Harmonics, Body, Immediacy, Dynamics, Bass, Space, Image Size, Decays)
A Medieval Christmas-Boston Camerata-Nonesuch H-71315 (Voices, Body, Space, Focus, Decays, Image Size, Harmonics, Immediacy)
La Spagna-Atrivm Mvsicae de Madrid-BIS LP 163/164 (Speed, Purity, Immediacy, Harmonics, Decays, Depth)
THE REFERENCE COMPONENTS
Reference Line Stages
THE RECENT FILE
Reviewing the Reviewers
My Audio Philosophy
My Audio SystemTop
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