"Jeff Liebermann"
"Phil Allison"

Guilty as charged. I misread the web page. Sorry(tm).

** You are not alone in that - most posters do not read what is actually
written and their replies show the fact by having little or no relevance.

For the record, what happened was that it was late when I originally
read the web page. The plan was to reply in the morning. However,
when I went back to the web page in the morning, the page wouldn't
load in my browser. (Trust me. This is not a fabrication). So, I
trusted my untrustworthy memory of the page to add my comment, which
was wrong. My apologies (again).

WS is the biggest offender by far.

If you find someone
misinterpreting what you wrote, I suggest you make an effort to
clarify your writings,

** My writing is not at fault.

WS constantly over-snips, ignores whatever context was there and just plain
misreads.


What fouled me up was the schematic.
http://sound.westhost.com/absw.htm

I'm used to seeing relays with coils and relay contacts with diamonds
for contacts. I also don't like connection tags style, where I can't
tell which way the signal is flowing. The schematic does not show a
box for the amplifiers or the "Y" adapter. With a quick glance, I saw
two relays and ASSUMED that one of them switched the input. I did not
read the entire description as I assumed that everything I needed to
know was in the schematic.

** That was idiotic - it take only a minute or so to read the whole thing.

Rod Elliot re-drew my had drawn schem his way - but it is perfectly clear.


So, who's at fault here?

** You alone.

You invented an non-existent problem with my idea BECAUSE you did not
****ing read it.


** You probably have heard of the Quad ESL63 speaker

Full disclosu I'm not into audio these day and know nothing of the
Quad ESL63.

** The ELS63s came out in 1982, sold in large numbers and is the best known
electrostatic speaker in history, later ( very similar) versions are in
production now - in China !!

Heaps about it all on the web too.


I will confess to repairing some audio equipment, but my
level of experience with modern hardware is essentially non-existent.

** That really shows.


One, fully tested ESL63 was compared with each production unit by placing
the two side by side with a flat response condenser mic on axis of both
about 2 metres away. The speakers were set up in an open area with a
thickly
carpeted floor and surrounded by acoustic screens. A square wave signal
was
supplied to both speakers at some mid band frequency. Next, the polarity
of
the new unit was reversed by a DPDT switch while the operator looked at a
scope screen showing the output of the mic.

The test was passed if the signal seen on the scope all but vanished !!

Not just a neat test, but proof that all ESL63s left the factory identical
in amplitude and phase response across the audio band.

Ummmm....

** WTF is that supposed to mean ?


http://www.stereophile.com/content/quad-esl-63-loudspeaker-page-2

** This has NO relevance top my post at all.


I don't know what went wrong. It could be the reviewer was
overdriving the speakers or that there was DC on the speakers.
However, if it was a defective speaker, the comparison test should
have shown that something was wrong.


** Did you read what I wrote THIS time ??

What does the last line say ??

Where is the Quad factory ?

In the USA or the UK ?

IIRC, the problem with arcing was due to the listening room being at high
altitude and that the reviewer was pushing the speakers to their power
limit.



.... Phil

WS constantly over-snips, ignores whatever context was there
and just plain misreads.

NOT GUILTY.

Everyone makes mistakes, but I'm not a consistent mis-reader. You are
confusing what people think they read with what you think you were saying.

"William Sommerwerck"

Phil Allison
** It did NOT have a tracking PSU - that is one of the many misleading
claims made about it. The "Carver Cube" as it as known was marketed as
something it CLEARLY was NOT and doing that is in breach of consumer
law.

One reviewer -- Feldman, I think -- was given a grossly inaccurate (ie,
totally fictional) explanation of how the Magnetic Field amplifier worked.
It was reported that he was very, very angry about this.


** I was given a copy of a US magazine ( Stereophile ?) back in the early
80s with several pages of description of Bob Carver's new wonder amp. It
spoke of "magnetic coils" and switching circuits that were never in the
actual product.

Seems Bob tried to make a tracking power supply that way, failed and
reverted to an alternative idea that used a phase controlled triac in the AC
to regulate the DC output of a conventional 50/60 Hz supply. He also made
the AC transformer ridiculously small.

On test, with both channels at full sine wave power under 8 ohm loads, the
AC tranny would make crackling noises and emit grey smoke within 60 seconds
of starting - the test then had stop immediately as the tranny has no
thermal protection. Very unnerving to witness.

The power amp itself used 6 DC supply rails and diode steering to reduce
heat dissipation. None of the above was new to electronics, except maybe for
the use of a tiny AC tranny in a 400 watt amp. The whole kaboodle was
crammed into a aluminium box of just under 7 inches per side.

Seems Bob kept the misleading name, "Magnetic Field Coil Amp" since he had
used it in some un-wise pre-publicity.



..... Phil

Those amps were ****ing junk. Much ado for nothing because they did not achieve any sort of efficiency in real life. I believe you about the one burning up right away, but did they all do that ? I would not be surprised. It probably had just enough to get through the standard IHF preconditioning.

The one I remember working on had a decent size transformer, but it was really flat, a toroid. I might be the only one around who actually saw a paper print of those things. For some reason he put the triac in the middle between a split primary. Seems to me it would be better off on the hot side.

It also had a commutating supply, and depended on the higher source filters to remain charged in case of a fast attack. If not the slew rate would have sucked. So would a few choice pieces of music actually. In my view, the amplifier should be ready IMMEDIATELY if not sooner to produce maximum output.

Carver lost me when he lost Phase Linear really. This and the echoplexified FM quasistereo were enough to turn me completely off. Just like the surround sound of today. Junk.

T

"Phil Allison" wrote in message ...

One reviewer -- Feldman, I think -- was given a grossly inaccurate (ie,
totally fictional) explanation of how the Magnetic Field amplifier worked.
It was reported that he was very, very angry about this.

Seems Bob kept the misleading name, "Magnetic Field Coil Amp" since
he had used it in some un-wise pre-publicity.

My memory is that it was even worse. The amp supposed had two signal paths --
a conventional path for "high" frequencies, plus a magnetic amplifier for low
frequencies. IIRC, it was this description that got to Feldman (in both senses
of "got to").