Toasted 200s! Need new output transformer?

[Anonymous]

My dad and I were working on a speaker cabinet that was giving me trouble tonight when disaster struck.

he was playing my bass into my 200s while I tried to keep the back from vibrating (which wasnt screwed on); this wasnt working so I removed the back from the cabinet when WHAM, no sound. something must have shorted out somewhere, and now the amp is dead.

I grew up with this amp, it's like an old friend to me. I have a much better rig these days, but this amp has a special place in my heart; and I'd hate to see it die in such fruitless way. my dad had JUST last week gone through and re-capped the entire amp, and finally got it back into working condition.

he's a busy guy, and he just spent all that time re-capping the poor thing; so I'm taking this project on myself as a learning experience. heres what I need to know:

we assume the output transformer blew on it; if you turn it up very loud you can hear a very feint signal.

it's definetally not the speaker, the cable, or anything else (our backup acoustic 150b plays through the cabinet just fine); is there any way it's NOT the output transformer that blew? it didnt blow a fuse, the tubes light up, everything seems normal except virutally no sound comes out of it.

if it IS the output transformer, where can I get a new one? I hear they are expensive and hard to find; anyone have any idea how much they cost roughly?

also, how difficult is installing a new output transformer, assuming I can get the one I need? is it a plug and play kind of deal, or is this a major pain to install?

while we are a sentimental family, we are also functional; if this whole thing is going to cost too much money then we'll just scrap the amp. I pray that this can all be resolved with minimal monetary damage!

I'd appreciate any help anyone can give me, thanks for reading my sad story!

~Lucius Bono

[Lucius Bono]

gah! rereading that, very little of it makes sense.

a few points to clarify: I was taking the back off the speaker cabinet when the sort probably happened. the short was likely in the input connector to the speaker cabinet.

as it seems more and more likely that the output transformer is the culprit, my research into replacing it has lead me to Hammond output transformers.

the Hammond 1650p has the same output as my 200s (60Watts) and takes the same kind of tubes; can anyone tell me if this would be compatible? obviously I understand that there are far more complicated considerations than tube compatibility and output wattage; but this thing is only $61, so I'm REALLY hoping it's the right one! walking away from this with a price like that would be heavenly.

but I'm a little worried that a cheap (or even different) output tranformer will effect the volume of this amp. it cranked before; but with a different (and probably cheaper) output transformer like the Hammond should I expect a lower output volume?

some of the things I said above will probably underscore the fact that I know little about any of this stuff; so please correct my technical grammar and assumptions as you see fit!

~Lucius Bono

[Anonymous]

Chances are your OT is not fried.. To check this take off the center tap of the ot ( usually the red wire, and measure the ohmage from the center tap to each plate lead ( the blue and brown ones ) the readings should be almost exactly the same from the blue one to the red one, and the brown one to the red one.  It doesn't really matter what reading is on the leads just that they are both the same.  Let me know how you make out  Good luck,  Bill Matthews

[Lucius Bono]

wow that's the best news I've heard all week! thanks for the help, I'm gonna check the OT out soon as I get some time.

if it's not the OT, any suggestions as to what it might be?

thanks again

~Lucius Bono

[Anonymous]

could be a bad preamp tube, bad phase inverter tube, etc  Just replace all the tubes and try it.  Let us know the results