Amp Comparison procedure. Amp off when not in use?

Turn the thing off.Better safe than sorry.

I don't see any problem with leaving a totally disconnected solid state amp powered up. But connecting or disconnecting either its inputs or outputs while power is on strikes me as an invitation to disaster, especially if the inputs are unbalanced rca's (which make the ground connection after the "hot" connection during insertion, and break the ground connection first during removal, thereby potentially injecting a huge transient into the amp's signal path).

I would strongly recommend that before changing any connections you power down both the amp and the component driving it, and then wait a minute or two for the amp's power supply capacitors to discharge. The couple of minutes that will take should allow the subsequent warmup to be brief.

Regards,
-- Al

Thanks guys for the quick responses.

Al,

Another question. So the amp is connected to the preamp via a pair of balanced interconnects. Would it be OK to leave the preamp on, but put it in "Mute" mode? the preamp is an ARC LS-25. My friend is bringing over his Spectron amp to compare to the Pass X350.5.

FrankC

Hi Frank,

Yes, I would think that would be ok, given that the preamp will not be putting out a signal (due to the muting), and given that the interface is via xlr's (which are designed to make the ground (pin 1) connection first, and break it last).

Enjoy!
-- Al