[maverickronin]

A thread created for discussions with analogsurviver so as not to derail other threads in Sound Science.
 
Inspired by manbear.
 
Now let us continue.  Last we were discussing electrostatic amplifiers...

 

[maverickronin]

Anyway, as analogsurvivor pointed out, it is indeed true that many (if not all, I lack the specs to say  for sure) electrostatic amplifiers lack the bandwidth to 20khz at full output.  Fortunately, this is not usually a problem since the energy of most most musical program material also decreases with frequency.
 
It could be a problem with some combinations of listening material, amps, and volume levels though.

 

[davidsh]

I've tried driving a 307, LS, and a Sigma NB at the same time on my T1. I listened to the Sigma at loud volume (famous for being hard to drive). Don't remember the sound deteriorating to be honest. Now, I only have the LS and Sigma with me.

 

[analogsurviver]

  I've tried driving a 307, LS, and a Sigma NB at the same time on my T1. I listened to the Sigma at loud volume (famous for being hard to drive). Don't remember the sound deteriorating to be honest. Now, I only have the LS and Sigma with me.

It is programme dependant. The most affected and easily audible are LOUD FEMALE VOICES. 
 
For this reason ( all kind of lesser equipment going "on strike"), later releases of even the likes of Barbra Streisand have been - squashed into something that can be played without the protest from most of the equipment. Taming the tigress into a *****cat in the process...
 
two examples : ( limited by YT - it is startling difference on vynil and a good turntable )
 

 

 
Once you hear it on these two tracks, it should be easier to pick it happening on other programme too. 

 

[manbear]

It is NOT about that - at all.

But it is. You'd have to be lacking social awareness to an astonishing degree if you didnt realize that you've been monopolizing the other thread.

Anyway, most of the members here have 3 kinds of cable: digital transport, line level connecting DAC and amp, and connecting amp to headphone (not electrostatic). None of those cables are sensititive to whatever differences exist between lamp cord and fancy pantsy silver wrapped in unicorn hair.

 

[davidsh]

 

It is NOT about that - at all.

But it is. You'd have to be lacking social awareness to an astonishing degree if you didnt realize that you've been monopolizing the other thread.

Anyway, most of the members here have 3 kinds of cable: digital transport, line level connecting DAC and amp, and connecting amp to headphone (not electrostatic). None of those cables are sensititive to whatever differences exist between lamp cord and fancy pantsy silver wrapped in unicorn hair.

I got them Stax :'-(

 

[maverickronin]

  I got them Stax :'-(

 
Me too.
 
I'll see if this limitation appears at any reasonable volume.

 

[maverickronin]

I turned it up uncomfortably loud with some female vocals and my 252S clipped first before I head anything so drastic as a 6db/octave roll off at 4khz...

 

[analogsurviver]

But it is. You'd have to be lacking social awareness to an astonishing degree if you didnt realize that you've been monopolizing the other thread.

Anyway, most of the members here have 3 kinds of cable: digital transport, line level connecting DAC and amp, and connecting amp to headphone (not electrostatic). None of those cables are sensititive to whatever differences exist between lamp cord and fancy pantsy silver wrapped in unicorn hair.

Yes, I did realize that I have been monopolyzing the other thread Precisely because everything that did not fit into the mold of the beliefs mutually shared got suppresed ASAP. The only difference is that the others who have not shared the same beliefs have chosen not to bother after realizing how things work on the other thread. 
 
Just because most of the members have only three kind of cable that are relatively easy, that does not give anyone the right to say that cables do not matter - even if only in cases that do not affect them directly on the personal level.
 
That is the same as to say that if 98,7654321 % people never require a medicine or medical treatment for XY, it should be declared that this XY condition does not exist. At all.
 
You can only pray never to be in that ( 100 - 98,7654321) % who happen to have that XY. 

 

[davidsh]

Regardless, why are Stax cables so poor? How would you design a more suitable cable that doesn't cost much?

 

[maverickronin]

Regardless, why are Stax cables so poor? How would you design a more suitable cable that doesn't cost much?

 
It's not they're poor, it's just that electrostatic amps are more sensitive to capacitance than dynamic amps.  They alread go to great legnts to reduce the cable's capacitance as much as possible.  I just measured the stock cable from my AKG K601s and came up with 355pf.  That doesn't matter to a dynamic amp which is designed to deliver high current at low voltage, the opposite of a 'stat amp.
 
If you wanted to reduce capacitance even further you'd have to do one of two thing, spread out the conductors even further from each other, or change the insulation material to something with a lower dielectric constant.
 
The first method would make the cable wider and more unwieldy.  Using something with a lower dielectric constant than PVC I assume they're made out of like tefoln or polyethylene would make it stiffer and less flexible.
 
There are several trade offs to consider.  Given the spectral content of most music, I don't think this isn't an issue which will come up often in real world use.  That last part is important to remember.  You can make any amplifier look bad if you feed it a signal far enough outside anything in real music.
 
EDIT:
 
Also I left out just making the damn thing shorter.

 

[analogsurviver]

  I turned it up uncomfortably loud with some female vocals and my 252S clipped first before I head anything so drastic as a 6db/octave roll off at 4khz...

You did NOT understand how ESL amps ( well, most of them ) work.
 
It would start rolling off above certain frequency under open loop condition - no feedback applied - regardless of volume . At low enough volume , feedback loop can compensate for the loss - by driving the output ever harder at ever increasing frequency - but this has a definite limit. And that is usually power supply of the front end of the ESL amp. Once this is reached ( many times prior to the hard clipping you drove iz into ), the slewing distortion or TIM goes trough the roof http://en.wikipedia.org/wiki/Slew-induced_distortion
 
There should be a LARGE difference between the 252S and T1-S - the later is at least two times more powerful and thus capable of maintaining higher output in the high frequencies. 252SS is likely not to be able to do mantain full level output above 2,5 kHz or so. If you still have the SRD-X; that should be less powerful still -
and would benefit one hell of a lot using really low capacitance cable - of exactly the type I was refering to.
 
Otherwise, one of the best and most dynamic speakers - ever - are Acoustat ESLs , driven by Acoustat amp modified by http://www.curcioaudio.com/ . As far as I know, he no longer modifies these units - but the main difference to stock amp was the replacement of the front end semiconductots by tubes - with MUCH higher voltage power supply, thus allowing for larger voltage swing, which all translated into yet one or two octaves higher without experiencing the above mentioned slew rate induced distortion - as compared to the stock amp. And that, whatever the frequency achieved, was enough to finally give the Acoustat the drive they need to really excel.

 

[analogsurviver]

Regardless, why are Stax cables so poor? How would you design a more suitable cable that doesn't cost much?

I will answer this later today - after a wake up etc. Trouble is, it will have to be custom made - no catalog I went trough did not have anything usable off the shelf.
 
What I did use does not satisfy safety requirements and will because of that not be shared. Although I have been using this cable for more than 30 years now.

 

[maverickronin]

  It would start rolling off above certain frequency under open loop condition - no feedback applied - regardless of volume . At low enough volume , feedback loop can compensate for the loss - by driving the output ever harder at ever increasing frequency - but this has a definite limit. And that is usually power supply of the front end of the ESL amp. Once this is reached ( many times prior to the hard clipping you drove iz into ), the slewing distortion or TIM goes trough the roof http://en.wikipedia.org/wiki/Slew-induced_distortion

 
I understood you quite well.  I'm saying that with the tracks I listened too it sounded like the amp got to hard clipping before the treble ran out of slew rate.
 
That's because they' were actual music and not a 20khz test tone.  Most of the energy is in music is in the midrange and bass.  If you feed a 'stat amp a single pure tone at too high a frequency then it is quite likely to run out slew rate first, but last time i checked most people didn't listen to single tones.

 

[castleofargh]

got to hand it to you analogsurviver, I disagree with so many of your opinions, but you're a fair player.
most of our usual customers would have already burst into hate rage and report everybody for not being nice to you.

let's keep arguing like gentlemen. you do make me wonder about a lot of stuff I never thought of.