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
I'm not here to denigrate or deny anyone else's tastes or findings.

Firstly, I never owned any versons before the IIz, and only heard a friends I many times as he sought to find an amp to drive them - Jadis, ARC, Krell, yada yada - he sold them.  The Scintilla's are the only speaker that was harder to drive and that's my experience in my 45 years in the hobby. 

There are tube amps that can handle CLS IIz's but they are either very expensive, or they are hybrids (as of about 2004).  I have never heard any tube amp under $15k that does justice to the bass - IMO.  Now it's been a long time since I've had them, and the state of the art has obviously moved ahead, so quite possible, but not in my time.

After I sold the CLS's, I had brief flings with the SL-3, Maggie 3.x, Quad 998?, and lots in between.  Retubing costs for amps, sourcing fancy types, and prior unsatisfactory results/cost has pretty much cut me off from tubed amps as a viable choice these days.  A preamp? - perhaps but I have a Pass L - which trounced my ARC SP-15; - I mean it was sad (do miss the polarity switch however) Headphone amp - perhaps, but I liked the Ragnarok more than the warmer albeit colored tube options at similar prices.  Coloration levels a magnitude better, and bass?  much better.  Oh yeah, a nice integrated amp too boot.

My favorite speaker of this century is the Verity Parsifal decidedly not a panel and driveable by tubes.  Still like the Pass X amps better than anything else on them, but, nothing really sounds bad on them - the spiritual grandchild of the ProAc EBS.


by far these panels are far better controlled with the High Current of a Solid State
Amplifier, where Vacuum tubes are Voltage driven .Current is what you need
to get ultimate control ,with a Vacuum tube preamp  you can still have the sonic signature  you want. I have used 100wpc tube smps with them but dynamics suffer say compared to a Pass labs 350 power amp.
Some of this bit of text appears to be a bit open to interpretation; if my read on it is correct than the basic implied statement here seems to be false. A high current amp does not do most ESLs justice. This is simply because there are no high current requirements.

Here's a bit of math: A Sound Lab, reproducing a tone at about 30Hz, with 200 watts to reach the desired sound pressure, will have a current flowing though it of about 2.6 amps. That's not a whole lot. The current myth is debunked. All that really happens with 'high current' amps (which is often a misleading descriptor in its own right) is a tendency to be bright, due to the 10:1 impedance curve exhibited by most ESLs.

Dynamics: in 90% of audiophile conversation usually the word 'dynamics' refers to distortion rather than actual dynamics. Usually the distortion involved is higher ordered harmonics (5th and above) and often in trace amounts (as far as a distortion analyzer is concerned). The human ear/brain system converts such distortion into tonality and also uses it to determine how loud a sound is, so an amplifier that makes greater amounts of higher ordered harmonics often tends to sound louder and also sometimes more 'dynamic' than an amplifier that does not make these harmonics in such quantity. Its a long-known fact that tubes make less of these harmonics. However, the impedance of the speaker also plays a role. A 350 watt solid state amp driving a Sound Lab will make about the same power as a 90 watt tube amp due to the impedance curve of the speaker. So the final statement of the quoted text also appears to be highly questionable- a lot depends on the ESL being driven!!
Bag, You wrote, " Firstly, I never owned any versons before the IIz, and only heard a friends I many times as he sought to find an amp to drive them - Jadis, ARC, Krell, yada yada - he sold them. The Scintilla's are the only speaker that was harder to drive and that's my experience in my 45 years in the hobby. "

I hope you don't think I disagree with what you say.  The IIz was a failed attempt to correct the impedance problems with CLS II, and the "z" mod didn't do much good.  My only point was that the original CLS, before model II, was the best of the bunch sonically and was an easy load for any tube amp. No one would recommend a tube amp for the Scintilla, of course.

We aren't quite in agreement, but in this hobby with so many people dying to disagree, I prefer to agree, or to find other people's ideas interesting and hopefully charming. 

Keep writing.




Well, we agree that the CLS IIz was best driven by an SS amplifier, and I added that this is because M-L were targeting such an audience and told me point blank that they were not interested in building a speaker for tube amplifier aficionados.