Re: Quad ESL57 and ESL63 transformer details.



Prune wrote:

Patrick, I mentionied a standard glass tube that handles 15 kV easily in
this very same thread: 715B

Maybe a pair of 715B will work in PP tetrode. But trying to run such HV in
leads from amp to speaker
is not user friendly.



I don't know why you insist on push-pull. You can drive each stator
single-ended by the opposing sides of a differential amplifier. One
stator is pushing when the other is pulling, then reverse (or maybe
that's what you meant, instead of the output stage to one stator being
push-pull).

A differential pair isn't a single ended amp; the diff pair or LTP has two
balanced outputs
if loaded by a CT choke or individual resistaors and 2H current cancellation
occurs in the
shared cathode circuit.



As for testing my theory, my listening experience is limited to
electrostatic headphones. I've listened to various of the Stax
offerings from the $50 ancient ones on eBay to the $2000 Omega 2s, with
many different amps, and I can tell you that there's a reason all amps
now Stax makes for its headphones are direct drive, as they most
certainly sound better than any of the transformer-coupled amps they
used to build in the decades past.

I was given a pair of Stax phones and drive unit which I stripped down.
The signal is rectified to generate a lasting charge on the panel. Its a
very simple arrangement.

Unless transformer technology has

improved enormously in the past decade or so, the choice for me is
clear.

Having direct drive is more a gimicky claim rather than technological
progress.
Transfromer design for such applications probably has not progressed much.
It hasn't needed to have progressed because it *is* effective.
The measured difference between direct drive and transformer coupling
is negligible.
Just exactly what is your technical objection to transformer use in ESL?
Please don't tender statements about "it sounds better"; that discussion can
wait until after you
prove transformers suck technically. Be brief in your concise explanations
please.



Sure, the headphones are at full blast with a mere 800 V peak to

peak, but there are reasonably easy tubes to drive at low-double digits
kV, such as the one example I already mentioned.

The 800V p-p is easy enough to insulate well in wiring which is so close to
a users head.

But having perhaps up to 20kV p-p is a different matter.


And even the ceramic
transmitter tubes are not hard to deal with if you can find the sockets
cheaply, and quiet cooling option (such as the conductive cooling
solutions that exist for the smaller ones). Probably better than the
danger of a fragile glass tube at that voltage anyway.

I will pass on this challenge to demonstrate to the world that direct drive
of ESL63
is easy and simple and safe.

Be my guest to prove to us all that direct drive is the way to go.

Patrick Turner.



Patrick Turner <info@xxxxxxxxxxxxxxxxxx> wrote in news:44C1E3AB.F341BFA7
@turneraudio.com.au:



Prune wrote:

"Phil Allison" <philallison@xxxxxxxxxx> wrote in news:4idse8F3b3nuU1
@individual.net:


"Prune"

** Idiot.

You misspelled your name.

But Phil is pointing out the actual voltages involved with direct
drive
of
ESL. Divide 18kV pk-pk by 2.82 and you get the Vrms a-a needed from a
PP
tube amp.
About 6,000 Vrms capability is required.
The transformer option remains the cheapest and most easily effective.
Even with tubes like 845/211, you's still need a step up tranny.

But don't let us stop you from demonstrating how much better direct
drive sounds
by assembling something yourself.

We leave you to find out your own truth.

Meanwhile, I still have no winding details for the ESL 63
transformers,
which
was what I wanted when i began this subject thread.

Patrick Turner.




.

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