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Krell preamp / Parasound amp power up issue

Hello everyone,

I recently purchased a Krell S-1000 preamp which sounds amazing when mated to my Parasound A51 amplifier. I'm having a few issues with the system, though. Here's what happens:
1. I power up the Krell, it triggers the Parasound with a short delay
2. Just as the Parasound is powering up, there appears to be some sort of spike/short, a low level thump will come out of the speakers
3. As this spike/ground loop/thump occurs, the Krell preamp will shut down,in turn powering off the Parasound because the trigger turns off

If I power up the Parasound first, there isn't an issue. Also, this doesn't happen every time I turn on the system, only sometimes. There's a ground lift switch on the back of the Parasound, I've tried both 'lifted' and 'grounded', get the issue on both settings. Also doesn't seem to occur when I use RCA cables, but there's less hum on the XLR connections and they sound considerably better, so I want to stick with the XLR connections.

I upgraded from an Integra DHC-80.2 also connected with XLR and it didn't have this problem.

My next plan is to try a two prong plug on the parasound. Anyone else have other ideas?

Thanks!
Chris
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cjwessing OP
32 posts
 
You guys are correct. I called Krell to ask about the issue, and his first question was "Are you using a power conditioner?" And yes, I am using a PS Audio Premier active conditioner, and it can't provide enough current when the amp turns on. The Krell senses the drop in current and shuts itself off.

Plugging the Parasound amp directly into the wall fixed the issue.
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