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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
zd542
5,339 posts
 
"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.
broadstone's avatar
broadstone OP
310 posts
 
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.
detlof
1,899 posts
 
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.
racamuti's avatar
racamuti
362 posts
 
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
almarg's avatar
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almarg
9,670 posts
 
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
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