Strange noise after amp's off ???


I'm new to high-end audio.
Simple question: why is there strange noise( something like "dong" sound ) from my speakers right after I turn off my int. amp ??? is it normal ? or what should I do to fix it ?

Spendor SP1/2
Plinius 8100.

Most-likely it's the way it is. I've never used Plinius 8100 but I assume that Plinius powers down rapidly with no delay.
I suggest using a power conditioner that will turn down your amp slow and you will hot hear any "dong" on your speakers. You will have to keep a switch on your Plinius always on.
Turn the pre off first.-?

I've asked the dealer, and he said that it is normal...
Anyway I'll try to get a power conditioner...

Any suggestions for power conditioner under $250 used/new???
A line conditioner won't resolve this but the turn-off noise is a non-issue. Switching off power at the conditioner isn't any different than at the amp, but the electronics should be left always on anyway. Lots of threads on this subject are available in the forum archives. A PS Audio unit might exhibit a slow decay shutdown, but I dunno that for a fact & beside that they are expensive & inefficient.
Have you looked to see if there's anybody in there? Safety first!

Sincerely, I remain
Hi. I have a Plinius 8200, which is very similiar. Mine does the same thing. I wouldn't worry about it. Most of the time, I just leave my amp on; it has a stand-by mode and a mute switch, so not much signal is going to the speakers. Have you thought of doing that? I only turn it off when I'll be out of town or if electrical storms are expected in the area (then I also unplug it).

Hope that helps,

two theories here:

• you’re experiencing “dieseling” that can be corrected with fuel injectors kept very clean;

• when you turn off your system, the sounds from the elevator can once again be heard (see, e.g., nanci griffith, “love at the five and dime.”)

My amp has a delayed shut off. I hear a soft sound like that first in the right channel, then the left. For my amp it is normal.
Hi Dan,

Thanks for your suggestion !!!
I almost forgot there's a mute switch that enables the disconnection of the output...

Besides, Plinius suggests to keep it on, accoring to the munual...

Thanks again !!!
You have inadvertently obtained a unit with the patented "Cat Alert" feature. The bong sound advised the household cat that you have finished listening and s/he may now resume sharpening claws on your grill cloth.
...what if there is no grill cloth?
Then God help your surrounds....