Re: Carver M500t Electrical buzzing after warm up


"DManzaluni" <dmanzaluni@xxxxxxxxxxxxxx> wrote in message
news:502ded92-1163-48cd-bebf-f4cd178a653b@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Apr 7, 9:18 am, Bruce Esquibel <b...@xxxxxxxxx> wrote:
DManzaluni <dmanzal...@xxxxxxxxxxxxxx> wrote:
Well that sounds more hopeful: I thought I had said that the sound
does come from the speakers: Apparently not! I might even be able to
do it myself if it is just filter caps: They tend to be relatively
separate from the rest of the internals. Is it this way in the Carver?
And how do I ascertain what the values are? I am in New York where
getting unusual caps shouldn't be too impossible.

I think I have bad news for you.

Unless that model was out of the series Carver made in the 1980's, it
doesn't
follow standard amplifier designs.

He (Bob Carver) used something he called "Magnetic Field" something or
other
and the power supply in there isn't like anything you can think of.

Basically they produced amps like the 1.5t where it could output 1200
watts
RMS (short term, like 4 or 6 seconds) per channel in a box that weighs
around 15 pounds.

The key was the power supply, it used some kind of "loose wound" core and
a special triac tied into it somehow that controlled regulation.

Although the caps probably can be found somewhere, I think the problem is
the transformer itself. They made buzzing noises in all the models and I
beleive it's from whatever they used to gunk the "loose core" inside of
it.

I'm saying it's more mechanical than electronic.

I think at this point in time you may only have the choice of finding
another
M500t which has some other problem and scavenge the transformer out of it.

If Carver is still around it's like so many other companies where it's
name
lives on but has nothing to do with what it made in the past.

Bob Carver is behind another company called Sunfire but I really don't
know
if they can or will handle problems with the old Carver stuff. I think
this was one of those messy situations where he signed over the patents
and
technology to the "new Carver" which went into the toilet.

A bit of history with that letter t after the model name, it stands for
"transfer function". In the 80's Bob Carver claimed that he could listen
to
any audio amp and copy the sound characteristics into his amp design
making
a clone of it.

One audio magazine (Stereophile) took up the challenge and brought him in
to listen to some high end, mega dollar amplifier. He listened and
tweaked,
listened and tweaked more, ending up with a virtual clone of the mega
dollar amp. Although the challenge was debated for years, it does seem he
accomplished his claim.

Thus all his amps ending with that letter t is supposed to have the same
sonic quality (however you want to descibe that) of that mega dollar amp
from the challenge.

-bruce
b...@xxxxxxxxx

But this isnt a mechanical sound coming from the transformer, it is an
electronic sound coming from the speakers



I've had some experience, years ago, with the Carver PM1.5 type amps. They
had a switched power supply via a triac. They also had a voltage adjustment
preset. If the power supply voltage was too low you could get constant
switching noise from the amps output. Correcting the voltage eliminated the
noise.

IIRC the voltages were around + and - 120v, perhaps a bit less - you might
want to check the caps' voltage rating and take adequate precautions!

(The PM1.5 used a dual power supply - the 120v supply was switched in to
drive additional output transistors when the signal exceeded that of the
lower voltage supply. This gave quite good headroom)


Gareth.



.

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