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It's obviously some type of tube amplifier...

DapperDee

DapperDee

New Member
fullsizeoutput_345.jpeg IMG_0341.JPG IMG_0343.JPG IMG_0346.JPG IMG_0354.JPG IMG_0353.JPG IMG_0351.JPG IMG_0350.JPG IMG_0349.JPG IMG_0357.JPG A friend passed this on to me and I'm wondering if anyone has any input, no pun intended, as to exactly what it is. I'm thinking, with my very limited knowledge, that perhaps it was used to send signal to multiple speakers hence the 5 speaker connections? Thanks in advance!
 
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That's a nice little all-triode PP amplifier. Might be a copy of a Brooke, or an RCA or Radiotronics manual design. One pair of taps might be the input, the others for different output impedances, or multiple speakers. Or it could be a driver amplifier for a larger transmittting amp. Can you show us the inside?
 
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Since the normally riveted bits are screw mounted, I suspect a kit, possibly from a transformer company.
Tube brands won't help identification.
 
one
now if you have a second one?
what is the chance you'll find another
 
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Well, it's not a Brooke. ;-) Definitely a homebrew job. Mono, with multiple impedance taps. Hard to tell what's going on in front, with those tags boards layered in there. Probably a late-40's design from Radiotron or a similar handbook. It could be a fairly sophisticated design.

Is there, by any chance, a number stamped anywhere on the output transformer (the one right behind the 6B4G's)?
 
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DapperDee said:
I wouldn’t even know how to get the one I have going
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Under no circumstances should you plug that in. Someone with experience *might* be able to get it going after a few days warming up on a Variac to reform the caps, and carefully monitoring it for shorts and such, but I'd be hesitant to try that myself. If I had it, I might do a complete teardown and rebuild, but it's a lot of work for a single channel. Too bad, it was probably a nice-sounding amp in its day, albeit with fairly limited bandwidth. A nice piece of audio history.
 
I’ll give it a very meticulous going-over in the morning to see if there may be a stamping on the chassis or info on the transformer. I do have a variac but believe me when I say that I had zero intention of powering it up. :no:
 
DapperDee said:
I’ll give it a very meticulous going-over in the morning to see if there may be a stamping on the chassis or info on the transformer. I do have a variac but believe me when I say that I had zero intention of powering it up. :no:
Click to expand...

Then you're aware of the risks. ;-) It might be worth restoring. PP 6B4G amps can be *really* lovely, but since there's only the one.... If the output transformers are of note it would be interesting to know.
 
probably was used for a multi-speaker setup, basically PA type work. Thats the only real use for 250 and 500 ohm outputs. Its basically equivalent to slightly more modern 70v speaker systems used now. You'd have a bunch of speakers with matching transformers spread around the place. Pair of 6B4's is probably good for around 10 watts in push-pull.
 
would probably make a fine guitar amp, provided its got enough gain. It has output taps for the usual speaker loads so it would match up to that without much fuss.

needs a rebuild of course, the caps in this are almost definitely shot.
 
Yeah, what gadget said. Those Stancor transformers are very good and very hard to come by anymore. Although, there's one on the bay right now if you want to build a mate someday. ;-)
 
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