I recently purchased a used Adcom GFA-535 amp and GTP-400 preamp.
Everything works fine except that the amp emits a very noticeable clicking
sound mostly from the right channel during use.  This is very similar to the
single click the amp emits when it is turned off, but the clicking during use
is produced when certain electrical devices (doorbell, some light switches,
fans, etc.) are switched on or off.
I've got all my audio equipment connected to a Triplite Isobar "noise filter 

surge suppressor" for computers, and I've even tried an APC surge suppressor 
to
no avail.
I've also tried an Adcom ACE-515 power line conditioner, but that didn't help
either.  It's connected so that my entire system powers up and down in stages
by using the power switch of the preamp.  This is all very nice except for 
he
fact that the amp emits an even louder click just after turning the
preamp off.
Are these clicks in any way damaging my amp or speakers?  They're not very
loud, just noticeable.
What's causing the amp to emit the louder click when hooked up to the power
line conditioner and switched via the preamp?
Is the Adcom line conditioner really any better than a good surge suppressor?
Is there any reason to keep it?  I've got a week to return it.
Suggestions?
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