Help: Tube Amps Pops Speaker Cone

Thanks Liguy. Looks like I have to ship this amp back to the workshop. The popping problem is in only one of the monoblocks. The humming problem is in both. Also, I forgot to mention: there is a buzzing coming from the transformers of both that cannot be eliminated with line filters or better AC cables or cheater plugs or ground switching (I did not go into the chassis to see if the screws are loose). And, finally, a little detail, these particular amps had to be precisely adjusted by a technician to my house voltage (because it was a little lower than standard) before I could use them. This adjustment was necessary because the heating of the tubes and their grid voltage is unregulated. Is there a SET web site or SET FAQ somewhere that deals with malfunctions?

I think I solved the popping problem inadvertently without changing a capacitor. I simply took out the VV52B output tube and firmly reinserted it. Popping was gone upon next start-up. What is this a sign of? A defect with the tube contacts? I think another audiogon member said that he fixed a sputtering problem on a Jadis push-pull amp by pushing down on the output tube while it was in operation. Why does this work?

Actually, this didn´t work for long. The sputtering is back, sporadically. The distributor has told me that it will not damage my speakers and that I can use the amp as it is. But I now need to turn the amp on, wait for a hum, turn the amp off, and then turn it back on, before it functions.

I'd send those babies back for a check up.