AprioriMark said:
jimh said:
'72 refurbed (by me) Fender Bassman 100 head
If you don't mind my asking, what did you do to it? I am always blowing transformers because of heat. I love how the thing sounds, and mine is ugly as sin, but I have never found anyone who could make this thing not EXPLODE from time to time.
-Mark
Randomly I saw it in a shop. I wasn't looking to buy an amp, but had to 'have a go'. The guy plugged it and switched it on, but one of the valves (sorry,,,,Tubes :icon_tongue: ) Didnt light up. 4x6L6s. Didnt bother me as there's nothing terribly complicated inside these things, so I made the guy a stupid low offer since it was broken. He accepted the offer, and I walked away with it.
Got it home, and replaced 1 large resistor which had cracked completely in half and the valve lit up and hey presto I got some audio. So the amp was working.
BUT, I then got a whole new set of valves, pre and power. The amp was pretty noisy and crackly, so I cleaned up all the pots with some contact cleaner, replaced the big power supply caps which were looking a bit worse for wear. I took out the strange bias balance circuit and replaced it with a regular variable bias circuit. Biased the new valves, plugged in, switched on and rocked out.
My Transformers are original but look to be in pretty good condition, so I dont really know how to help you there. Are your tubes biased properly? They could be working too hard and pushing the tranny past its comfort zone?? I'd have thoughts it pretty unlikely as Fender used to go overkill on the transformers. Correct speaker impedance? Mine has a fixed 4ohm (non-switchable) output transformer, so I rewired my Orange 2x12 for 4ohms (2 x Celestion V30s 8ohms parallel). If you've got a speaker impedance mis-match that would definitely blow your trans.
Mine sounds brilliant now. No noise (apart from a small hum when its cranked up really high - you get that from any valve amp regardless of how new or old it is). Really powerful, clean up until the about 6 on the master vol so you can really hear what the drive pedals are doing. Its classic fender clean yet pushy (not drivey, but pushy, cant really find a better way to describe it), but it will break up nicely if you really crank it. Loud as hell through my Orange 2x12 though.