I have a small solid state amplifier (receiver) and speakers which I use
for my computer sound. It sounds good. Much better than those amplified
"computer speakers".

But I have determined that it is never shut off. When I push the ON-OFF
switch, the sound stops and the pilot LED goes off.

The switch is NOT on the line cord, but somewhere inside the circuit.
(No schematic available). I have determined that it's never shut off
completely. When it's turned off, if I put my ears right to the speaker,
I can still hear a very slight hum. My kill-a-watt meter shows it's
always drawing .05 amps when it's turned off.

I'm sure that small power draw only costs pennies each month for the
electric, but its still a waste of power, and I prefer ALL electronics
are completely shut off during lightning storms.

What the heck kind of a circuit would be used to turn it off, but still
leave it semi-powered? And why????

For now, I put it on a power strip, but that strip is not always shut
off, when I am recharging my computer (laptop) battery. I am probably
going to put one of those inline line cord switches on it. But then I
will have to turn on BOTH the line cord switch and the built in one.
(Not that this is a huge problem).

I dont understand why anything would be designed this way. There is no
remote control, so it's all senseless.... and poor design. My only guess
is that it stays powered so it can retain radio stations in memory.
(Stereo Digital Synthesize Tuner with push button presets). But I never
use the radio part of it anyhow.

If I could find a schematic, I would try to modify the internal
switching. But I have tried to get one, and they do not exist. (This
receiver is probably from the 80s).

If it was not for the fact that it has great sound, and a built in
equalizer, I'd probably just replace it. Low powered solid state
receivers or amps are easy to find and cheap to buy.