100W PT in a 50W head

Folks, are they any issues with swapping out an 50W PT with a 100W PT. The reason is i like running my 50W jtm45 clone full tilt and I keep popping the HT fuse intermittantly. The current PT is from a '65 Bassmen head and Im thinking its arcing over from overcurrent in the secondary B+ and thus popping the fuse. I'm running the filaments on a separate tranny so its not the filment winding overheating.

 

I'm using a weber copper cap for the rectifier, and I've used different sets of output tubes with the same result. The reason I suspect the PT is that its old, and the PT was in a previous amp where I blew the mains fuse by running w/o a load (it was hooked up to a talk box and i forgot provide a load). I've checked the bias ckt, filter caps etc and everything looks good. I also removed the end bell of the PT and found a lot of shellac or whatever sitting in the bell.

 

hmmmmmmm, I've run this same set of tubes in my 100W plexi clone full tilt with no probs at all. Maybe its that copper cap. So ur saying that PT ('65 bassman) should be able to handle running 2 el34's full tilt with no probs.?

 

I've been using 500ma slo blo and fast. Thats right for 50W's right? Maybe its old tube sockets. They're pretty old although i've scrapped 'em clean btwn pins.

 

the HT fuse is in the PT center tap to ground. I've monitored the current in each tube with the 1 ohm resistors and at idle I get 34ma per tube, then while plugged in and playing hard open E chords each tube conducts from a low of about 110ma per tube up to about 210ma per tube with amp cranked into matched resistive load. While monitoring I've never yet reached up to 500ma total current thru the HT fuse. So there must be an intermittant short somewhere.