Reverb feedback

[AWR07]

Hi. I’m the proud owner of a 5:25 express combo. Version 2 with the EQ. I previously owned the original. Loved it. Something I’ve noticed with the newer one is without the foot switch connected I am getting a lot of what sounds like popping, but what is the reverb kind of chiming through the speaker when I switch channels or wattages or even modes. I wasn’t sure what it was until I plugged in the foot switch and by clicking the Reverb off all of that noise when away. All I hear is that quick click which is what I am accustomed too. To me this doesn’t seem right. I tested with the foot switch disconnected and the reverbs dialed to zero. Again the noise was gone but with it set to 12 o’clock once again it was there. While not serious in nature (or so I think) it’s a little annoying. I swapped out the Reverb tube but no real difference. It’s under a 90 day in store warranty. I’ve taken it back twice. First time the tech did replace the power tubes, which was great. Bias checks out. But this is being deemed as normal. Perhaps it is but it wasn’t evident on my original Express. Or the Mark 3 or 4 or 5 that I previously enjoyed. Any opinions. Should I consider swapping out the other 4 preamp tubes? Not something I want to do but you never know.

 

[Don]

Unless you've got super sensitive hearing and are hearing things that most people can't, that's not normal.

Make sure you're replacing the correct tube. I believe it's V5- the one that'd be in the position of the phase inverter in most amps.
You could try replacing the other tubes in case one is microphonic. I also recommend that you clean the tube sockets with a little DeoxIT D5 or other contact cleaner without lube in it (I spray it on the tubes' pins rather than in the sockets and work them in and out of the sockets). You'd be surprised how many issues are caused by dirty jacks and tube sockets.