I bought some new jj kt88s and they felt quit loose in the socket. I played the amp for a while and then I noticed one wasn't glowing so obviously the contact is bad. I pushed it around and got contact but then noticed that I got some static noises. I put my old electroharmonix back and everything is fine.

I'm pretty new to tubes but is it normal for different manufacturers tubes to not fit?

have you considered tightening the contacts in the tube sockets?

never experienced with power tubes but with signals some mfg's may use a larger dia pin.

What is your amp. Tubes them selves would not have a "loose" pin connection or the tubes would not function because of vacuum loss
if the structure was compromised. In all likely hood the tube amp pin sockets are loose or you have an intermittent solder joint on the tube socket.

definitely not solder as the original tubes are fine. I could tighten but what a pain, is that normal just to accommodate a different brand of tubes?

JJ tubes had thinner pin issues in the past.

tighten contacts in tube sockets and while yer at it give em a cleaning too.

and yes, jj tubes have been mentioned to now have thinner tube pins.

http://billmaudio.com/wp/?page_id=171

the tube base and/or pins could become loose. the pins don't pass through the glass, the wires they are soldered to do.

Duh, I wasn't thinking....typically power tubes have the leads exiting the glass it is the smaller tubes such as 12xx7 where the pins are directly in the glass envelope. Thank you for your vigilance.