Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Marcus on March 15, 2014, 08:25:46 am
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Just got a B52 ST100 head for really cheap. I tested the power transformer and it's shot. I contacted B52 but they never got back to me. I can't even find a schematic for this amp. Not that I would be able to spec it out if I had one. Somebody help a noob out! Thanks
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Unfortunately there isn't a "universal" power transformer that we can recommend for you, that will fit the bill...
There's lots to be concerned about when choosing a PT, and if one spec doesn't match, then it's just not a match.
Contact B52's manufacturing company and see if you can get an OEM replacement
http://www.b-52stealthseries.com/start.html (http://www.b-52stealthseries.com/start.html)
IF YOU'RE 100% SURE THAT THE PT IS DEAD, AND IT'S NOT JUST A BLOWN FUSE, BAD SWITCH, ETC., ETC. ETC........
Power transformers do not have a high failure rate, so any time we hear a noob say his PT is bad,,,,we all think :rolleyes:....here we go again :icon_biggrin:
I contacted B52 but they never got back to me.
Call everyday until they are sick of hearing from you.....squeaky wheels eventually get greased
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Schematic is here , second answer ;
http://music-electronics-forum.com/t9765/ (http://music-electronics-forum.com/t9765/)
If your amp is a 100 watts with 4 X 5881 , it is easy to find a Output Transformer with good electrical specs.
Most difficult is the size , dimension , will it fit in the amp ?
Look here , this one ;
http://www.tubesandmore.com/products/P-T1650R (http://www.tubesandmore.com/products/P-T1650R)
Be sure you know how to test OT as you say and there is no electrical short in the amp to blow your new Otput transformer
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Schematic is here , second answer ;
That schematic is for an AT-100. His amp is a ST-100. They are not the same.
If your amp is a 100 watts with 4 X 5881 , it is easy to find a Output Transformer with good electrical specs.
But he doesn't need an OT. He needs a PT.
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And the solid-state circuitry inherent in the B-52 amps might rule out all the common 100w power transformers.
Another reason why it's best to buy it directly from the company. The problem is the company office is in California, while I'll bet manufacturing is in China, meaning the corporate office may not carry stocks of spare parts...
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I have a schematic for it , it should help if you have to get a PT for a 3rd party , if so try Mercury Magnetics.
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It's a 100W Fender PT plus a 24V-30V AC _CT_ transformer for the low-volt stuff.
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Sorry , I give information for the wrong transformer ( OT ) you need Power T . Not easy :BangHead:
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How do you know it is bad? What test? Should be a huge chunk of iron and I would think it would take someone bypassing the fuse. What caused it to go bad? Did the person you got it from give you any information as to doing something like putting foil on the fuse?
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How do you know it is bad? What test? Should be a huge chunk of iron and I would think it would take someone bypassing the fuse. What caused it to go bad? Did the person you got it from give you any information as to doing something like putting foil on the fuse?
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