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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
detlof
1,899 posts
 
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. .
broadstone's avatar
broadstone OP
310 posts
 
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.
audioconnection
1,270 posts
 
""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

timo62
278 posts
 
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.
atmasphere's avatar
atmasphere
11,577 posts
 
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.
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