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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
timo62
281 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
11,931 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.
detlof
1,899 posts
 
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!
broadstone's avatar
broadstone OP
310 posts
 
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.
in_shore's avatar
in_shore
596 posts
 
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 .
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