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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.
128x128broadstone
atmasphere's avatar
atmasphere
11,954 posts
 
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.
broadstone's avatar
broadstone OP
310 posts
 
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.
atmasphere's avatar
atmasphere
11,954 posts
 
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...
labtec
189 posts
 
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.
broadstone's avatar
broadstone OP
310 posts
 
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.
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