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Why do McIntosh SS amps cut out?

I have known quite a few old SS Mac's. My main amp is a 2205 and I've just picked up a 2505. These, and every other old Mac I've run across seem to have issues with shutting off one or both channels. Switching on and off will usually get it to stay on. Is it just bad switches? It seems more like it is seeing static/noise and going into protection.
mr_work
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ivanj
35 posts
 
what's upstream?
aball
2,016 posts
 
Never had that problem with the 4 SS McIntosh amps I have used/own. Ivanj has a good question - downstream is another possibility if they all used the same speakers. I don't think it is the amps if they are all doing it - it would be way too much coincidence. Good luck!
meisterkleef
146 posts
 
That's usually a relay going bad. The way to test for sure
is next time a channel cuts, instead of cycling the power
off/on, turn off the speakers and turn the volume up about
3/4 for about 5 - 10 seconds. Turn the volume back down to
normal and turn the speakers back on. If both channels are
back it's definitely a relay. Sometimes cleaning can help
sometimes they're shot beyond hope. I'm sure Mac has the
replacements if necessary.
theo's avatar
theo
2,660 posts
 
I would say it's in the POWER GUARD circuitry and it should pay a visit to Binghamton NY and see it's mother.
Chances are it's older design is just worn out. Also you maybe driving some hard to drive speakers i.e. varing resistance or possibly cross overs failing but I would lay a bet it's the PG curcuits though
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