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Using tube amp with electrostatic speakers.

Moons ago I started similar discussions and thought I had been given enough good advice not to approach the subject again. Here goes anyway. I've used Martin Logan electrostats for well over 30 years with quite a few different amps but have recently switched to a tube amp and dynamic speakers with which I am very satisfied.  It consists of the Cary Rocket 88R amp and Serie Reference 3 speakers. 

My brother was visiting last week and was so impressed with the sound that he decided that he might want to try a tube amp also (probably the same one as mine).  However, he is using a pair of SL3's that I gave him years ago and I'm concerned primarily about the current requirements of the Martin Logans as well as other concerns that I'm not thinking of.  I don't want him spending money on something that may not bring him improved sound so would appreciate more advice to pass on to him.  He currently uses a Rogue Audio SS amp with his SL3 speakers and, to me, it sounds very good. 
jimbreit
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ivanj
35 posts
 
tomcy6:

Here is Dick Olsher on "Curvilinear" diaphragms from Sterophile:

"A truly curved diaphragm (à la MartinLogan) can have wide horizontal sound dispersion, but the problem is its limited linearity at low frequencies, where large excursions are required. When the diaphragm is pulled forward, it is stretched, increasing tension. When pulled back, its arc of curvature decreases, which causes it to lose tension. This difference in tension in the two halves of a push-pull cycle severely limits the linear excursion range where distortion will be low. What's a poor designer to do?"

Read more at http://www.stereophile.com/content/sound-lab-1-electrostatic-loudspeaker#KSGYY7hMRcYqtpsY.99



lewm
13,169 posts
 
That's a well known question for Martin-Logan's design.  Most ESLs are not curvi-linear, however.  Most are truly planar.  The Sound Labs may appear to be curvilinear, but the apparent curve is composed of an array of planar facets, created by stretching the mylar over a frame.  Apart from the SLs, almost every other ESL is flat in fact and in outward appearance.  None of this pertains to the ease or lack thereof of driving ESLs with this or that amplifier.
tomcy6's avatar
tomcy6
2,597 posts
 

ivanj, I think that Dick Olsher was repeating Sound Lab's marketing explanation of why their flat panel design is better.  If you compare the in-room frequency response graphs of the Sound Lab to the ML Montis, the Montis looks pretty good:
http://www.stereophile.com/content/martinlogan-montis-loudspeaker-measurements#dcpcdPYl2Q74hhzt.97

I'm not saying that the distortion you refer to isn't real, I just don't think it's a major factor in the speaker's sound quality.

erik_squires
16,235 posts
 
@tomcy6 An "autoformer" describes the construction of the output transformer, while "output transformer" describes it's function.  In this case they describe the same part of the amplifier.

In an autoformer there is no secondary winding, and therefore, no galvanic isolation compared to a dual coil transformer.

Best,


Erik
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bdp24
9,868 posts
 
I believe Roger Sanders was involved in the design of the original Martin-Logan model(s), but now disavows the curvilinear principle and design, not using it in his own ESL.
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