Hi all, running a pre-owned SE34I.5 in my second system, powering a pair of Zu Dirty Weekend 6.

I've noticed that when I power the amp down, within 10 seconds or so, I hear a soft squeak come from my speakers. The kind of squeak you hear when barely letting air out of a balloon. Very strange! Is this normal or indicative of a tube problem? Don't get anything like this from my UFO25s in my main system.

Thanks!