Best tube amp for electrostatic speakers


For over 35 years I've almost exclusively used either ribbons or electrostats with solid state amplification and have been generally happy with the sound. Over the last several years, though, my hearing has become somewhat degraded and more sensitive to certain frequencies. The frequencies which seem to cause the most discomfort occur in the 1400 to 1900Hz range and come across as "bright" to my hearing. After researching this matter and having been given some expert advice, I've decided to pursue the idea of replacing my present amplification equipment with tube based gear.

The purpose of this post, then, is to solicit advice regarding the best approach to making this decision based on the following information: the current basic equipment is Shanling Solid state CD player, Peachtree Audio Nova used as preamp, two DBX 1531 EQ's to help compensate for age related hearing loss, Peachtree 220 amp, Silversonic T114 cable and Martin Logan Ethos speakers.

The listening area is our living room measuring 15 by 22 feet with my listening position 16 feet from the plane of the 2 speakers which are positioned 11 feet apart measured center to center. Located between the 2 speakers is an entertainment center which is about 9 feet wide. My listening interests are varied from solo guitar and light jazz to occasional orchestral music. I don't generally listen at high volumes and am not particularly interested in strong bass except for the rare action movie background.

Unless not advisable for some reason, I would like to keep the Peachtree Nova as a preamp because of the significant latitude for source connection and what seems to have a decent internal DAC. If this option would substantially defeat the purpose of the intended modification I would work around it. I can no longer deal with sounds that are "bright" which I now find uncomfortable but detailed sound is very important.

So, the questions are: is the move to tubes the best option and, if so, what might be some reasonably priced amps that could accomplish the goal. This, of course, would take into consideration room size, etc. for determining power requirements. If there are other more practical and less expensive options to consider, I would appreciate that advice as well.
broadstone
Boadstone,

Please tell us more: Does this brightness you describe, occur at every soundlevel from ppp to fff and when listening to music, which instrument or voice tends to irritate you the most, when you are listening to what music at what sound level?

I feel this is a delicate problem, which has to be approached carefully. The problem could in fact lie anywhere. Do you only listen to CDs? If yes, how old is your Shanling?

Unfortunately I don't know your Peachtree gear to have an opinion on their sound, but I know the Shanling and that it can sound harsh with certain CD's.
There is a (small) chance, that even a change of cabling could do the trick at lesser cost. Have you ever tried that?
I have Ethos front speakers and used two BAT VK 60 as momo blocks and had great results. If fact, with those ML speakers, one stereo would do.

Really, with a Peachtree Nova you would be well with any qualité tube amp, outputing over 60 watts.

I am cutting back on music, and now use an older Classe SS amp.
VAC power amp.
Sounds as if I Have same hearing issue using Ribbon speakers. Switched to BAT REX amp and worked out great . VTL,manley also good choices
Detlof, at low volumes I experience no discomfort at any frequency but at "normal" levels there are ranges of frequencies, as I pointed out, that bother me especially when from a percussive source like a piano. It might be important to mention that the problem was somewhat worsened when I switched to the Ehos speakers from the Odysseys. The Ethos seems to do a very good job in the upper mid frequencies, maybe too good. To answer the question about speaker cable selection, my original thread was started with that subject in mind but I decided that my issues warranted a little less subtle approach and that I'd address the cable issue later.

One thing I've learned which is contrary to the assumption that proper speaker positioning should be much simpler with these speakers because of the smaller transducer panel compared to the Odysseys. That's simply not the case and their positioning may be even more critical which reminds me of another point; I was able to achieve a somewhat warmer sound toeing them in several degrees more than the recommended starting point of aiming them so that one is listening to the inner 1/3 of each speaker.

As far as the CD player is concerned, most of my evaluation has been in listening to lossless files synced from iTunes to the Apple TV. It's the simplest way I have of switching between various genres for comparison of different instruments. I hear no difference, though, listening to either source. The CD player, btw, is about 10 years old and I'm not using my DAC's as I'm depending, so far, on the Peachtree internal DAC which is supposed to be decent.

EBM, thanks, I will look into the VAC as one of the choices.

If you are serious about tubes, I would start with a tube DAC and then maybe a tube preamp. Both uses the smaller signal tubes. A tube amp uses the larger power tubes and they can take a bit more care and feeding.

That said, tubes and planar speakers can sound magical. I have owned tube electronics with some type of planar speakers since the late 1980s. I currently own Martin Logan SL3 speakers driven by an Audio Research Ref 110 tube amp and LS27 preamp.
Take a look at the Carver 350 Black Beauty mono blocks. The 350's use six KT-150's per side and can drive just about any speaker. The slightly older version of the Black Beauty's, the 305's uses six KT-120's per side. I use these amps on my Magnepan 20.7's and they sound fantastic! The 20's are a demanding load, but the 305's never seem to run out of power.
"So, the questions are: is the move to tubes the best option and, if so, what might be some reasonably priced amps that could accomplish the goal."

There's no guarantee that tubes will help. They can be bright just like SS. I would focus on getting the right gear regardless of whether its tube or SS. Also, just getting something that sounds rolled off/warm, probably fix your problem. I think your issue is more of a timbre/refinement problem in the high frequencies. For example, a cymbal can often sound like a harsh noise, and not a cymbal. If you can correct HF problems like that, you should be able to listen to your system.
Wolcott "The Presence"(& later 220M/P280) amplifiers were supposedly designed specifically to drive difficult loads like electrostats.

Here is a Enjoy The Music review where The Presence are thrown at Sound Lab A-1's and their very difficult 40 to 0.8 ohms load. The also do well driving Apogees

Henry Wolcott passed away a couple of years ago, I think. But, you can still find the amps for sale used in great condition. They don't use any exotic tubes, just 6550's. and are supposedly bullet-proof
Broadstone,

Thanks, I now understand better I think. I do have another question though. With piano at the higher register does the sound just become harsh or does it also break up, slightly distort? From what you say, the latter does not seem to be the case.
I have been using stators, like you, for over 40 years and have tried many forms of amplification, settling finally with Atma-Sphere, which contrary to the Wolcott mentioned above, never gave me any trouble. The Wolcott sounded great, but alas, my unit was anything else but bullet proof. VAC, BAT, VTL and Manleys are all good choices to my ears. 60 watts should do you fine. Peronally I don't think amps from Audio Research would solve your problem. If possible I would try before I buy. .
ZD, you summarized my inquiry better than I and hit on one of the issues that has been in the forefront of my thinking, the factors associated with timbre. Even with my age related hearing issues, in my uneducated way I still believe that those frequencies that are beyond audible have some importance in overall sonic quality. To some extent I was able to demonstrate this when I added the EQ's. When setting them up I used my audiogram to establish a baseline slope. In this exercise I pretty much ignored adjusting those frequencies above about 8000hz because they were beyond my audible range. At first I thought that the equalizers compromised my sense of timbre which is one of the most important factors in my listening enjoyment. Before I removed them from the system, though, I continued messing with them and discovered that boosting those frequencies above my way upper limits improved the sound to the extent that even I recognized it. You also mentioned that tube amps, out of hand,are not necessarily the answer because some can also be bright, a fact that I had already discovered a couple of years ago when I traded my Rogue Audio Sphinx for an integrated tube amp which was so bright sounding that I kept in the system for only 2 weeks.

Also, years ago I thought that my sensitivities were related to the higher "tweeter frequencies" and I experimented with tweeters to no avail. In the process, though, I discovered that good tweeters seem critical to timbre. As stated, my sensitivities are related to frequencies in the 1400 to 1900Hz range corresponding, on a piano, to somewhere above middle C.

Lostbears, good suggestion; sometime today I will reinstall one of my tube DAC's to see how much that helps. I should have been a little more clear, though, regarding the fact that I'm looking at the possibility of switching to a tube based power amp based on advice from a very well respected audiophile here on Audiogon.

Detlof, thanks again and to answer your question, the upper middle frequencies produced by the piano don't seem distorted, just harsh to the point that at normal listening volumes (I know....whatever that means) it can actually cause me to wince.
""The frequencies which seem to cause the most discomfort occur in the 1400 to 1900Hz range and come across as "bright" to my hearing""
""Located between the 2 speakers is an entertainment center which is about 9 feet wide.""
Have you tried less toe in?
Where are the speakers in relation to the wall unit?
JohnnyR

Broadstone ,
I had the same issues years ago and the switch from solid state to tube solved my problem.
It is true that tube gear can be bright sounding also. The trick there is to finding the brand/model that fits into your liking the most.
Also , by changing the tubes in that particular unit , you can refine the sound even more into the realm of your liking. Certain tubes will give you more of a detailed/extended sound and others can add warmth with a little less detail and everything in between.
I still have to be careful as to what I add to my system. One step in the wrong direction by adding a new piece of gear, cables ,tubes can take it out of my comfort zone.

Do you have any friends or a local dealer that could let you try their tube equipment, different speakers/interconnect cables and cd player? Try changing one piece of gear at a time and see if it helps you out.
ESLs traditionally are a tricky problem for solid state amps. The reason is that solid state amps are often able to act like a voltage source, which is to say that they can often double power as the load impedance is cut in half.

This causes troubles with ESLs, as unlike cone-based speakers with a box or baffle, the impedance curve of the speaker is not an efficiency curve as well. IOW, the speaker has the same efficiency at all frequencies. Additionally, the typical ESL has an impedance curve that varies about 10:1 if it is a full-range system. For example, Sound Labs vary from a high of about 30 ohms in the bass down to about 1.5-3 ohms depending on the position of the Brilliance control. The Quad ESL57 varies about 45 ohms in the bass to about 4 ohms in the treble.

So the ability to double power as impedance is cut in half does not help so much- you get too much high frequency energy. This is why tube amps are usually the preferred amp if you run ESLs.

However Martin Logan has understood for a long time that solid state amps dominate the market, so they have kept their impedances low in order to limit the amp's ability to double power. As a result they are often only 0.5 ohms at 20KHz! To drive this with a tube amp a set of ZEROs is a good idea
http://www.zeroimpedance.com

The more feedback the tube amp has, its likely it will also sound brighter for two reasons. First, most applications of negative feedback contribute to brightness as it causes the amp to make higher ordered harmonics (while overall dropping the THD) which the ear/brain system uses to detect loudness (which is another way of saying that our ears are very sensitive to higher ordered harmonic content; much more so than human vocal frequencies). The second reason is that the more feedback is used, the more the tube amp will try to behave as a voltage source, which does not work so well with ESLs as previously explained.

More:
http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

So- I would get the biggest tube amp you can that does not run negative feedback, and get a set of ZEROs so the amp can handle the otherwise difficult load. This will get you the speed and delicacy ESLs are known for, but without excess brightness.
After all is said and done, I would follow Zd's advice. Regretably I have no experience with your amplification, so anything I might further say, would only be a wild guess.
Please let us know, when and how you resolved your problem and happy listening from a stator lover to another!
Audioconnection, there is approximately three and 1/2 feet between the sides of the entertainment center and the side walls with the speakers approx 1 foot away from the sides of the entertainment center. They are forward of it by 1/2 foot with the transducers about 4 feet from the back wall. Also I actually found that toeing the speakers in more than the ML inside 1/3 rule works better for me. As soon as I have one of my grandsons available to help remove the heavy bridge between the towers on the entertainment center I will reinstall a tube DAC and not do anything else until I see how that works out.
I would look into Atmospheres amplifiers for Electrostats , over the years I have listened to a few systems using Atmophere amplifiers and preamps that I thought were very good match with eletrostats , this pass holiday season a real surprise was Atmosphere M1 preamp and 60 watt monos driving Reference 3a Veena B and source The Beat turntable , very impressive indeed .
@Atmosphere, I have been mulling over the 'Zero's' as one possible solution to an impedance preference for an 16 Ohms output, which is unfortunately, a winding not available to me from a potential replacement amplifier that I am currently demo-ing.

Amongst the many plaudits for the Zero's, I have however noted one or two comments that make mention to a perception of a *very* slight degree of smearing to the presentation
@Atmosphere, I have been mulling over the 'Zero's' as one possible solution to an impedance preference for an 16 Ohms output, which is unfortunately, a winding not available to me from a potential replacement amplifier that I am currently demo-ing.

Amongst the many plaudits for the Zero's, I have however noted one or two comments that make mention of a *very* slight degree of smearing in the signal with the Zero's in the chain.

I would be most interested in any considerations or experience that you may have on this matter.

Jasper.
Broadstone,
I only saw Atmaphere's post now and I cannot emphasize enough to read his post carefully and to follow his advice. He is an expert and he knwows what he is talking about.
Here you have knowledge and experience versus just opinions and predelictions.
One has to be careful with the ZEROs. Like anything else they can be mis-used. Generally I go for the least amount of multiplication that gets the job done.

With ESLs this generally means you are trying to restore lost highs. What is nice about the ZERO is if you have an 8 ohm cone woofer you might just use the ZEROs on the ESL panel and let the woofer run direct. This gives you a little flexibility when doing the setup.

Also, be aware that they need about 45 minutes of warm-up before you take them seriously! This befuddles A/B experiments but it seems to be very real.
Atmasphere, thanks, and I apologize to all about the double post. I've had an issue with forum signin and sometimes the only way to get back into the forum is to start a new thread. Anyway yours was the kind of education that I needed. I've spent 55+ yrs in this hobby but have never been a student of it and is now why I'm having to ask so many questions. Regarding the ESL impedance curve, if I'm understanding the explanation, the impedance effects of my newer Ethos speakers should be somewhat less significant than the Odysseys that they replaced because of their smaller size and the more limited lower range capability of the panels. It seems to me, then, that my issues with upper frequencies should be somewhat reduced using these smaller panels. However, that doesn't seem to be the case.

A question I have regarding your discussion of feedback is that if it results in an increase in upper level harmonics, would that not also enhance perception of timbre?
For some time now I've suspected that there is some sort of antagonistic relationship between timbre and brightness and, because the timbre issue is one of the most important issues to me and brightness is my least acceptable, I seem always to be walking a tightrope between the two. Of course, my perceptions and ultimate conclusions regarding this interpretation could be way off base.

Your explanations, at least to the extent that I think I understand ithem, make a great deal of sense and I hope that my comments do them no injustice. It will, though, take some time for me to digest and expand on them before I comment further.
For some time now I've suspected that there is some sort of antagonistic relationship between timbre and brightness and, because the timbre issue is one of the most important issues to me and brightness is my least acceptable, I seem always to be walking a tightrope between the two.

This is a common problem! The thing to understand here is that the brightness caused by distortion does not contribute to timbre at all- instead simply makes the presentation more irritating, as the ear finds the higher ordered harmonics to be less pleasant.

To get timbre right, you have to have low distortion and pretty good bandwidth, and the distortion has to utterly lack any of the higher orders (5th harmonic and beyond).

In many amplifiers the feedback is poorly applied, the result being that those harmonics are injected into the resulting output. This has been known for a very long time as Norman Crowhurst was writing about this problem over 50 years ago. This is not to say that feedback in an amplifier won't work, but until the advent of simulation, its been almost impossible to do the design correctly using the traditional formulae.

So as a result many designers got it wrong- and the amps they made tend to sound bright. I find that many audiophiles tend to prefer sins of omission rather than commission...
I run Zero's on all my speakers (Maggies) and they even help SS amps.

On my other system, I use a SS McIntosh on my Wisdom speakers and that amp includes autoformers...so they don't just benefit OTLs.

Personally, I haven't seen the problem that Ralph mentions about overusing them (i.e. using the higher multiples), but autoformers are really speaker tweaks and not amplifier tweaks, so it will really depend on each speaker.

Maybe he can elaborate on his experiences with multiplying the impedance too much and/or any suggestions for the optimal impedance target range for his amps and others.

Even though I don't use his amps, Atmasphere is someone's advice you can really rely on and trust...which is very rare on these boards.
I may be in over my head in my following comments but here goes. In the process of trying to determine where my hearing is most sensitive I used a test CD which steps sound frequencies from 20Hz to 20kHz. This is how I found that frequencies between 1400 and 2000hz are the most uncomfortable. The recording, supposedly presents fundamental frequencies throughout the test range so upper level harmonics based distortion would be minimized. However, because the CD is being played through my amplification equipment, and if this equipment is what's adding the distortion, whether or not it is the base frequency or the distortion of it that causes my specific problem isn't resolved.

I tried the same test using a computer based tone generator and got the same results, though, so I'm beginning to think that at least a big part of my issue is a simple sensitivity to those fundamental frequencies between 1400 and 2000Hz which, btw, correspond closely to the frequencies of my tinnitus.

That being said, and assuming that distortion, in my case at least, is not the only factor producing harshness, I'm now concerned that simply changing my amplification equipment may not be the answer. Because I now use EQ's, I could attenuate the culprit frequencies but even I know that this is would introduce potentially worse problems.
Perhaps I'm being naive, so forgive me for asking, but have you ever tried the same procedure you describe on another system? If not, you could perhaps narrow down your problem even further.
I should mention though, that I presupposed, when writing the above, that you ran your computer based tone generator through your system as well.
Running tones like that is not a good way to tell what's going on- you are not the only one that would find tones like that unpleasant. In fact all the audiophiles I know don't listen to raw tones.

If you find a particular recording that seems unpleasant on your system, it might be worth it to play that recording on another system and see if you still think the same thing of it.
Thanks. That, of course, makes sense and I have tried the same offending CD's on 2 other systems, one of which was my own located in another room; the other was a setup belonging to a friend. I found the discomfort to be similar at the same point in the music from all. I guess that should tell me something but I'm afraid to conclude what.
Running specific tones probably won't help you too much as already stated. However, I can tell you a couple things I do to A/B speakers and identify a variety of issues.

1. Run pink noise through speaker A and then speaker B. You can probably hear differences even in mono, but go to your listening position and compare in stereo too.

In my experience, whichever you think sounds better with pink noise will usually correspond to better sound when regular music is played.

It's not a scientific or full-proof method, but considering the primitive material some people use as "reference" tracks, it's no worse and makes it much harder for you to be fooled by biases or other things going on with more complex music (i.e trying to judge vocals, bass, soundstage, extension, sibilance, etc. all at the same time).

2. Leverage technology. I use Jriver as playback for digital material and there is an option under DSP playback to see an "Analyzer" on screen while the music plays. It will give you a good idea of the frequencies being reproduced and their "volume" relative to other frequencies.

You might ask.."How does that help me?"...Well, it first helps you from making inappropriate conclusions.

For example, I've had more than a few audiophile friends use a particular test track as their "reference". I was often surprised that they would sell certain high quality speakers that they said were too bass heavy, while cheaper monitors sounded better to them.

Come to find out...if you look at the material via the Analyzer, it SHOULD sound bass heavy at certain points. That's how it was recorded. The amount of sub 100hz material is double what is over 600 hz for most of the song.

A lot of what people pass around as "audiophile" recordings are not really good to use as a reference. They just sound good. A true "reference" requires something you can compare with in real life. Since most people aren't at the live studio recording, your best bet is to listen to acoustic music and/or leverage technology to at least give you data about how the original recording was mixed.

For those with ears that qualify for Mutant X-Man status, these tips are unnecessary. However, I've found them helpful.
Broadstone, If that same CD track is what irritates you on other systems, one strong possibility is the recording itself, unless you used the same CD player in those systems as well.

How about this- are there any recordings that sound fine on your system and are not irritating?
Atmasphere, in each system that I used for this test the players were different; one is my own which is the Shanling CD-100, another is an old Theta, and the third source is our Apple TV playing Apple lossless files. The results are the same in all cases using multiple CDs when the offending frequencies come up. For example, I can't listen to anything Celine Dione sings except at VERY low volume. Mostly, though, because much of my listening is to solo guitar, there are only a few passages that bother me so, yes, most most of what I listen to is pleasing and I generally enjoy my system very much.

Labtec, I got out the old test CD and tried listening to pink noise but didn't quit get the part about a comparison. The test disk presents pink noise starting at the left speaker, then right, then simultaneously, both in and out of phase. The thing I didn't expect nor understand is that the out of phase sound was almost exclusively from the right speaker. I'm sure I'm missing something here.

Broadstone Hi.

Written bench test results from one review on ML Ethos:
"Measured overall impedance was low at 4 Ohms, in fact surprisingly low considering the bass unit is powered. This is due to the electrostatic panel that comes in hard at 400Hz our impedance analysis shows, careering down to 1 Ohm at 20kHz – ouch!"

I'll look for graphs that back this test statement up.

But from what was said to get the very best from the ML Ethos you need an amp that can that can deliver good current down to at least 2ohms, so it stays flat over the frequency range, and not start behaving like a tone control at different load impedances.

That means "close" to doubling the 8ohm spec wattage to 4ohms and again doubling to 2ohms

EG:
8ohms-50watts
4ohms-100watts
2ohms-200watts

Cheers George
George, this is my 6th pair of Martin Logans and I've seen the graphs so your observation is absolutely correct. I'm using a Peachtree Audio 220W power amp but I don't know how adequate its current capabilities are in regard to the impedance increases that you describe. However, I'm 72 and starting to be convinced that a significant part of my problem is related to hearing changes that have occurred over the years.
Here's my 2 cents. Cables and power conditioning. I had stats for years, later monitors. I love the piano. It's much more difficult to reproduce accurately than vocals. I use a certain track on George Winston's close mic'd 'Plains' as a test. Certain notes were like the proverbial fingernails on a chalkboard. And this is on a system with a high end tube preamp and tube monoblocks. After a year and of half of tweaking, I finally discovered what mix allowed it to sparkle. It took a lot of tweaking. Years ago, when I spoke with Bob Crump about his modding process, he said it came down to pain-staking trial and error - and a lot of patience. Agreed. My solution was cables and power conditioning. YMMV.
Broadstone...if your pink noise test is coming exclusively from one speaker when out-of-phase, then you have some major issue in your system.

Testing phase with pink noise phase is a very easy test that even non-audiophiles can identify. When out-of-phase, the sound should come from the individual speakers and not in the center. Anything that happens otherwise, indicates something is seriously wrong. It's not even something debatable or questionnable.

It sounds like you have a channel balance issue (at a minimum). The bias or tubes can be seriously off on one channel versus the other...or you have some other type of EQ or defective component messing things up.

I'll also say that your sources are far below reference level, even if operating correctly. A Shanling CDP, Apple TV, or old Theta will not provide reference level playback...In fact, it won't even be close to reference level.

Nevertheless, the reason I recommend the pink noise test is due exactly to what you noticed. Regardless of how bad your source, it still shouldn't make a pink noise test come only from one channel when out-of-phase.

I hate to be the bearer of bad news, but you have something wrong with your system.

On the flip side, doing the the pink noise test and getting such wacky results was enlightening and will help you at least identify which piece in your system that is defective.
The Peachtree 220 from what I found can almost double into 4ohm giving 400watt but I can find nothing into 2ohm.
If it gave 600 or 700 into 2ohm then this is the sort of amp that would not whimp out into the 1ohm of the the Ethos.
And at 72 years old you don't want an amp that is going to curtail the upper mid/highs, because it's here where the Ethos are that heavy load of 2 to 1ohm, that will make a whimpy amp sound soft and dull.

Cheers George
Sorry. me chiming in again. Labtec is right of course about how out of phase pink noise should be presented. Also, to be frank, your system is not exactly state of the art and especially CD from the eighties until about the turn of the century might, when played through it, sometimes sound as you had described.
However, I would suggest, that before you start exchanging gear, I would check at your next visit to the specialist, if you've started to hear one sided. It may not, as Labtec suggests, be just your gear, it may well be your hearing, although age induced hearing difficulties generally lead to loss af hearing in the upper frequencies, not to perceived distortions. But again, I strongly suggest, to clear up this question first with a specialist, before you tear your stereo apart.
"Labtec, I got out the old test CD and tried listening to pink noise but didn't quit get the part about a comparison. The test disk presents pink noise starting at the left speaker, then right, then simultaneously, both in and out of phase. The thing I didn't expect nor understand is that the out of phase sound was almost exclusively from the right speaker. I'm sure I'm missing something here."

For the in phase test, pink noise coming from the left speaker should sound like its coming from the left speaker. Same thing with the right speaker. Both speakers simultaneously in phase should come from a center image between the speakers, just like a main vocal track.

If both speakers are playing pink noise simultaneously, but out of phase, the should be coming from 1 side. The location is usually somewhere between one of the speakers and the side wall.

If you're still not sure, there is an easier way to do this. First, play a CD you know well and that normally has a strong center vocal image. If you do hear a center vocal image the way its supposed to, that will indicate that you don't have a phase problem. (The type of phase that we are talking about here. There are different kinds of phase related issues.). I recommend you do 1 more test, just so you know what this type of thing sounds like. Go to just 1 of your speakers and reverse the speakers cables position on the binding post. (Put the + speaker cable on the - terminal, and put the - speaker cable on the + terminal.) Now, if you go back to your listening chair and play the same vocal track again, you will then see the vocal image shift to one side.
Something wrong is right. The difference between in phase and out is dramatic; when standing nearly centered in the plane struck from one speaker to the other, the in phase sound is centered and the out of phase sound has the perception stereo but more or less equal in volume left to right. In the out of phase mode as I move away toward my listening position the sound moves incrementally to the right. When I retreat all the way to my listening position the sound seems like it's coming from over my right shoulder. I did these tests with the equalizers bypassed but I'm not confident that their presence in the system may still not be having an effect. Anyway, it's worrisome and apparent that I have a significant problem somewhere but haven't yet figured out where to start looking.

To put to rest the issue of needing a hearing specialist, I've been to 3 audiologists, one of which is a tinnitis specialist. I know what my hearing deficiencies are and have used my audiograms to design base slopes on the EQ's. As I've gone into detail on other threads, I can't wear hearing aids because of the extreme sensitivity of my ear canals. For purposes of this discussion,though, my hearing issues are not dramatic but, typically, exhibiting a nearly equal bilateral drop off beginning at about 4000Hz.

ZD, I've tried exactly what you suggested and got the results that you describe but that was before adding the equalizers. I do believe that one of them (right channel), btw, might have a problem. The next step, then, is to remove them and start the evaluation again. Once I get the issue that I'm working on resolved, it isn't high on my list, but I may be looking for an upgrade to my CD player which I've had for a very long time and continue to be quite happy with.
If removing the equalisers from your system and reevaluating does not change your perception of the out of phase pink noise, you could perhaps also start looking at your room.
Hi Broadstone, Take a look at the Wolcott amp that is for sale at the "audio asylum" market. This amp is ideal for electrostatics. I don't know the seller, but it looks like a good price (4800.00).
Good luck, Tish
01-13-15: Georgelofi
But from what was said to get the very best from the ML Ethos you need an amp that can that can deliver good current down to at least 2ohms, so it stays flat over the frequency range, and not start behaving like a tone control at different load impedances.

That means "close" to doubling the 8ohm spec wattage to 4ohms and again doubling to 2ohms

01-14-15: Georgelofi
The Peachtree 220 from what I found can almost double into 4ohm giving 400watt but I can find nothing into 2ohm. If it gave 600 or 700 into 2ohm then this is the sort of amp that would not whimp out into the 1ohm of the the Ethos. And at 72 years old you don't want an amp that is going to curtail the upper mid/highs, because it's here where the Ethos are that heavy load of 2 to 1ohm, that will make a whimpy amp sound soft and dull.
In fairness it should be pointed out that there are many audiophiles and designers who would disagree with these statements, on both theoretical and empirical grounds. The relatively high output impedance/low damping factor of most tube amps, especially those using little or no global feedback, and the inability of such amps to double power into halved load impedances, will in combination with the impedance vs. frequency characteristics of the Ethos and most other electrostatics certainly result in less emphasis of the upper octaves compared to the presentation that would result with most solid state amps. However which of those presentations is more true to the source material, and which of those presentations is more subjectively preferable, and which of those presentations is less likely to trigger Jim's (Broadstone's) specific hearing issues, are separate questions.

And while it is true that when working into an electrostatic such as the Ethos the use of a tube amp, especially one which uses minimal or no global feedback, is likely to result in voltage vs. frequency characteristics at the input terminals of the speaker that are less flat than would result from the use of most solid state amps, it by no means necessarily follows that the frequency response characteristics of the acoustic output of the speaker will be flatter in the latter case. As can be seen in the comments by Ralph (Atmasphere).

Also, regarding the amp's ability to deliver adequate current into low impedances, it should be kept in mind that most music contains far less energy in the treble region than at lower frequencies, especially in the upper part of the treble region where the speaker impedance becomes really low in the case of the Ethos and many other electrostatics.

Regards,
-- Al
Al, are you a trained EE ?
Your technical level of knowledge seems far beyond anybody else on here. A great asset to say the least.
Thanks very much, Schubert. I appreciate the nice words. To answer your question, yes I have BSEE and MSEE degrees, and 33 years experience designing and managing design of analog and digital circuits for defense electronics. I'm now happily retired :-)

Best regards,
-- Al
Thanks, Good thing you're retired.
I saw yesterday our new Congress is adding another 150K
green cards for foreign engineers because we don't have any American ones, at least ones that want to work at 1/2 pay.
We need Chinese EE's working in defense jobs.
Regarding availability of engineers, its very much supply and demand. The demand is huge and the supply of really good ones limited.

I wish education and engineers, doctors, nurses, teachers etc. got more respect in American culture in general. They are the ones that should have awards shows, not those being sold by the Hollywood promotional machine.

Most good engineers these days seem to come from countries where most are disadvantaged and science and math are and potential career in engineering is highly valued still as the ticket to a better lifestyle. Its just the way it is.

There are probably more good engineering schools in teh US than ever before, but its still a supply and demand thing.
It's tough enough for us to find systems that fulfill our wants/needs without trying to find equipment that "repairs" auditory limitations. You mentioned that a perçussive source such as a piano bothers you. I wonder if that is the case with live piano music? If not, then obviously your responding (bothered by) your present audio setup. But you've probably already made that distinction -- performed the is it live vs recording reproduction test.

I'm in agreement that your sources are less than reference level. Since its inception the silver disc has presented brightness issues that are nicely ameliorated by some of the better, more current digital sources.

With that said, I run stats in both my H/T system and in my 2-channel audio room -- Martin Logan's & Aragon 5-channel ss amplification in the former and Soundlabs & CAT tube amplification in the latter. Of course each room sounds different, but neither has objectionable frequency ranges.

My suggestion is to be very careful trying to correct objectionable frequencies with a specific design/type (e.g. tube) equipment. In your shoes, I suppose I would try to find a system at a friend's, dealer's, audio show that doesn't bother you to make sure that the problem isn't an organic one. And if not, try new sources and amplification (perhaps even speakers) until you find a combination that you can live with.

At any rate, good luck.....
Broadstone, look and you can see in the graphs 1 2 & 3 of the new reincarnation of the highly regarded Mcintosh 275.

You can see that the black trace is what happens to the frequency response of the amp that can't do current as I've outlined above into a simulated dynamic speaker load.
The upper mid/ to highs are considerably rolling off, and the whole amp is acting like a tone control

Now into the 1ohm of the Ethos this will be even more rolled off, as it is much more severe.

http://www.stereophile.com/content/mcintosh-mc275-power-amplifier-measurements

Cheers George
Now this is the actual simulated speaker load sterophile use.
Overlay it with what's above and you can see that the Ethos is going to be much lower at 1ohm in the upper mid treble. And therefore will severely roll off in this area.

http://www.stereophile.com/content/real-life-measurements-page-2

Cheers George

Regarding the measurements cited in George's two posts just above, I would emphasize that the frequency responses and rolloffs that are described apply to electrical signals at the amplifier output/speaker input, not to the acoustic output of the speaker. As I said earlier:
01-14-15: Almarg
... while it is true that when working into an electrostatic such as the Ethos the use of a tube amp, especially one which uses minimal or no global feedback, is likely to result in voltage vs. frequency characteristics at the input terminals of the speaker that are less flat than would result from the use of most solid state amps, it by no means necessarily follows that the frequency response characteristics of the acoustic output of the speaker will be flatter in the latter case. As can be seen in the comments by Ralph (Atmasphere).
The successful pairing of tube amps with electrostatics by many experienced audiophiles, as can be seen in system descriptions and posts here and elsewhere, confirms the importance of distinguishing between flat frequency response into the speaker, and flat frequency response out of the speaker. They don't necessarily go hand in hand, particularly in the case of electrostatics. IMO.

Regards,
-- Al