[Audio Empire]

On Wed, 1 Dec 2010 17:30:16 -0800, Kele wrote
(in article ):

I felt the Amp; I leave it on all the time normally. The pre-amp was
also on; nothing playing volume full off. Amp kinda warm (ADCOM 8200
250 watt x2). Turned off preamp; will check amp sink temp in a couple
hours to see if different with preamp off. Probably should disconnect
the RC jacks too? Ok, they're unplugged at the amp. The two pieces
are on the same AC circuit but different outlets. Ok, the preamp is
unpluged from the AC; there is now nothing physically connecting the
preamp and amp.

You are saying the Dolby circuit not functioning is a symptom of the
power supply having a problem.

NO, I am saying that the DC offset that has the speaker cone moving out in
response to the volume control setting is the symptom of a problem with the
power supply. Somehow, you've got DC in your audio, which you should not
have. Based on that, I'm postulating that the power supply problem is LIKELY
the problem with your Dolby decode circuit as well.


Check this out one more time... The
speaker extension (moving and holding in the outward position) ONLY
occurs when the Dolby circuit is selected. When Dolby is not
selected, the speakers don't extend. When Dolby on, the sound that
does come through the speakers isn't good, but when Dolby is off, the
sound is normal with all other DSP options, five channel, and two
channel. I was thinking that it's only the Dolby circuit because
everything seems fine with Dolby off.

Then the DC is getting into the audio via the Dolby circuit. Perhaps an
op-amp has failed, of perhaps even the Dolby decoder chip itself. At any
rate, you need to have the pre-amp looked at by a pro, unless you know how to
use a voltmeter or an oscilloscope to do troubleshooting yourself. At any
rate, it's doubtful that even if you can find the problem, given today's
surface-mount components, that you could fix it yourself.