I have the original version of the CSP. When I run it through my Audiolab 8200P power amp, I am getting very noticeable, very loud hum. I have tried with a different solid state pre-amp in the same configuration, so I know it's not a ground loop. I have tried all the usual trouble shooting procedures, and even turned the gain pots inside the pre-amp all the way down. The hum always stays the same.

Anyone have any ideas?

I've had it for a few weeks. It hummed right from the first time I powered it up.

The volume of the hum is always constant, regardless of the gain settings or the volume pot position.

It only hums when hooked up to solid state amps. I tried 2, and it hummed the same with both of them. When I hook it up to my Decware Zen, no hum. Dead silent.

Maybe it just hates solid state?

I haven't tried swapping the tubes, since I don't believe it's a tube issue, otherwise it would hum with all amps.

Thanks for the advice. Makes sense.

Kinda disappointing, though.