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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
georgehifi's avatar
georgehifi
10,312 posts
 

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
broadstone's avatar
broadstone OP
310 posts
 
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.
georgehifi's avatar
georgehifi
10,312 posts
 
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
Post removed 
labtec
189 posts
 
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.
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