Why do my speakers "POP" when I turn off preamp?

Turn off your amp first and then your preamp!
Turn on your Preamp on first and then turn on your amp.

Okay, thanks! I was following C-J's manual and it said I could leave the amp on 24/7, but that I should turn off the preamp when not in use, which extends the life of the tubes. Guess that isn't a good idea in this case! After the first time it happened, I started turning the amp off first, but thought there was something I was missing (I don't have a mute button, and the volume control does nothing in this case).

I've had three CJ based pre-amp/amp systems and always turned off amp first (they were all tube designs) and waited about 1-2 min then turned off pre. If you turn off pre but leave amp on you're allowing some voltage to leak into speakers which causes popping sound - not a good thing.

Dawgcatching,

When you shutdown your preamp - it's circuitry goes through
a "shutdown transient". That is as it loses power, the
circuitry goes through a type of "death throw".

Some amps and preamps have a "muting circuit" to disconnect
the output before the transient. Yours evidently doesn't have
that circuit.

You should always power up your equipment in the direction of
signal flow - source components on first, then preamp, then
finaly power amp.

When you shutdown your system - the order is reversed - the
power amps should be shutdown first. So if you follow
the proper shutdown order - the power amps should already
be shutdown when you turn off the preamp - so the shutdown
transient won't damage the speakers.

Note - the power down transient of the preamp may not be
suppressed by the volume control - depends on the preamp
design. So you can't depend on a volume control to save
your speakers.

As Paul suggests, learn / practice proper startup / shutdown
proceedures before you damage your speakers.

Dr. Gregory Greenman
Physicist