Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TubeGeek on January 11, 2012, 09:43:30 pm
-
I am not sure where to begin with this one. I replaced the caps in the amp and then the owner did some changes to the pots (not wiring just relocating pots) and added a 3 prong cord himself.
When I finished replacing the caps I could not power on the amp because I was missing some of the jumpers that are needed to power on the amp. I gave it back to the owner and he said he'd be ok powering it on after he received the re-tolexed cab he was having done.
Couple weeks go by and I get a call saying that something snap crackled and popped when he applied power. :BangHead:
I was hoping it would be obvious when I got it back. Nothing seems obvious to me. The design is different than I am used to. It's made by a guy named Ken Verlage in Canada. That's about all I know about it. I cannot find any schematics either.
I have stared at the wiring, trying to find a clue or indication of an error or problem. Nothing so far.
If any group of people can help me tackle this challenge, it's you guys. :help: Normally I may opt out of this job but the owner is a buddy of mine sorta and I want to help him out if I can.
:w2: Now where do I begin? :dontknow:
-
Point to point in what looks like a recycled chassis. Fun.
Sorry, I'm no help but I can empathise with you. :dontknow:
-
Yes, the chassis looks very much like a gutted Fisher chassis to me.
The only smart thing to do is to trace out everything that's there, and see if you spot obvious problems.
-
Crack and pop ????
Did you check output tube bias ?
This amp is a real mess. I can't understand that somebody built that and sell it . The guy who built that have probably a schematic or he follow a well know amp's schematic with EL34 like Marshall ?
-
> looks very much like a gutted Fisher chassis to me.
I was going to say "almost a gutted Bogen".
It's clearly a store PA chassis. 25V tap, remote page socket.
> I am not sure where to begin with this one.
Same as a clogged hose. Disconnect where the water comes in and see if that flows. In this case, disconnect after line switch and fuse. Then fix that and disconnect after PT. Still no excitement? reconnect PT to heaters, then rectifier, then power tubes, until excitement happens.