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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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audiojan's avatar
audiojan
393 posts
 
Could it be that the current draw exceeds what the power line can deliver? You will have a spike at start up and I'm thinking that you might have something else on the same breaker that is causing this instability...
ghostrider45
449 posts
 
Try disconnecting the remote triggering of the Parasound. Power up the Krell manually, then manually power up the Parasound. See if you get better behavior that way.
wolf_garcia
6,644 posts
 
Ah...the "brown out" syndrome when a high current amp fires up (after everything else is on for a minute) there's a little spike, although I've found with better amps it's not audible in the speakers generally. I doubt it's a grounding issue and I assume the Krell senses the little electron rush and decides to duck. This is another reason I'm thinking about dedicated lines for this stuff, along with keeping the system off the lighting circuits. You could get a power re-generating conditioner although they're often expensive.
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