Speaker noise after tube amp shut down

I did't swap speaker cables yet but I will tonight. Right now I'm not home.
Power tubes are KT88, NOS Genelex Gold Lions.
I will let you know how swaping going.
Thank you!

Got a spare set of tubes? How old are the tubes? When was the last time you replaced them? After swapping the cables, I would try changing all the tubes just to see whether the issue is caused by the tubes or not.

FrankC

Last nigh I swap speaker cables and interconections from preamp and this eliminate speaker or preamp. Also plug diferent power tubes and problem is same. Only thing wich I didn't is to change preamp and driver tubes. I will swap them tonight and see.
Thanks!

You should swap the tubes between the left and right channel; if the sound moves, then it is in the tubes and not the capacitors. If it doesn't move, I would suspect an electrolytic capacitor. If it moves, then swap the small signal tubes to determine if it is those tubes or the power tubes. Keep doing the swapping until you figure out which specific tube is at fault.

I've had several small signal tube (6sn7) that made noise (popping and whistling noises) on power down, but were otherwise quiet.

Finally I found problem.Problem is bad preamp Brimar 4004 tube.When I pluged different preamp tubes no problem at all.After I power down my amp my speakers are quite like should be.
Thank you all for yours inputs!
Ilija