[WireNut]

A tip for tube preamp users. Tonight I put back by tube preamp in my system which has 4-6922 tubes in the preamp. I made sure I pushed the tubes all the way in the tube sockets of the preamp. I turned the preamp on and the left channel was noisy and hissing. Also, the right channel was lower in volume.

 I took a kitchen plastic spoon and tapped on the left channels tubes and low and behold the noise and hiss went away in the left channel. Then I tapped on the right channel tubes and I'll be damn, the volumm now matched the left channel equally. Everything now sounds even with no tube hiss or noise. I can't explain why this happened but it did. All 4 tubes where tight when I first plugged them in the sockets but tapping on them fixed the problems in both channels. Go figure.

Anybody found this out before?

[FullRangeMan]

False contact happen by socket fault, but not good beat energized tubes.

[WireNut]

My right channel has been lower then the left for a long time. Never knew tapping on the right side tubes with a plastic spoon would fix the problem.
Looks like I found a tube tweak

[sebrof]

Doesn't sound fixed to me. Better keep that spoon handy...

[steve in jersey]

It may be time to clean your preamp's tube sockets & then the pins on your tubes before re-inserting them !

How long has it been that you've noticed that channel imbalance ?  Did you change the tubes as a matched pair & do you think there is a possibility that 1 of the tubes wasn't  as in "spec" with the other from the start ?

On the other hand it may have just been some mysterious anomaly , but don't be surprised if that tube decides to "Give up the Ghost".

It couldn't hurt to perform some preemptive cleaning , so you can at least rule that out ! (Hopefully, it's not a premium NOS tube that decided to act up; For myself it normally was a NOS tube that decided to act up !!!)

[WireNut]

Yeah I think I need to clean the tube socket pins and the tube pins of my ARC LS7 preamp. It's been sitting in the closet for a year or so. I was having the same problem with my Sonic Frontiers SFL-2 preamp but I never tried the spoon tweak and ended up selling the SFL-2. Now I'm using and ARC LS7 which is probably 20-25 years old.

 I turned the ARC LS7 preamp on again today and the left channel was noisy again. A light tap with the plastic kitchen spoon made it dead quiet again. Time to clean the sockets and tubes and see if that fixes the problem. But I'll still keep the plastic spoon handy. Who Knows. 

Maybe I could patten the plastic spoon tweak