Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: gfarina55 on August 02, 2021, 10:18:49 pm
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Schematic attached. I've had this old Bogen PA/record player with 2x6V6 and a 5Y3 rectifier sitting around forever. I know folks make these into guitar amps, and I'm wondering if I could reuse the transformers for a Tweed-style build? What circuit might be appropriate for these transformers? I've done simple repairs and built a couple Tweed-style amps from scratch, but I'm probably not skilled enough to analyze this circuit myself and mod it for guitar amp use. Ideas welcome!
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antique electronic supply has these neat mounting plates to convert an octal socket hole to noval: https://www.tubesandmore.com/products/covers-chassis-socket-hole-steel
you could make a tweed deluxe with one tube reverb or a tweed bassman/deluxe mashup with the three preamp tubes (this is probably what i would do)
sounds like a fun project!
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Deluxe 5E3, Princeton Reverb, Harvard 5F10, Plexi 6V6, and on and on.
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It ought to play as-is, through the MIC input. These were sweet livingroom amps.
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Thx for the ideas!! Could I use these transformers in a Harvard or other amp with the same power tubes and rectifier, or are there other considerations?
It ought to play as-is, through the MIC input. These were sweet livingroom amps.
You have to have the platter running to play it as-is. Learned the hard way by playing a gig with it until it started smoking! The cap can marked "phono motor" is now a pile of ashes.
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> You have to have the platter running to play it as-is. ...The cap can marked "phono motor" is now a pile of ashes.
Well, that can't be right. What if you mostly wanted to play the radio? Don't see a cap-can for the motor. My dark suspicion is that this smoke was already planning to escape, and your playing was the last straw<G>. 60 year old caps tend to smoke for no special reason.
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Interesting, that amp has a raised heater ground going to the cathodes of the power tubes...
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while i have limited experience looking at 50s amp schematics (compared to 60s and 70s, say), i haven't seen much heater elevation in production amps but wouldn't put it past the bogen engineers who seem to have been quite crafty and bright (the ht voltage doubler on the chb35/chb50 chassis i've picked up is neato!)
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> You have to have the platter running to play it as-is. ...The cap can marked "phono motor" is now a pile of ashes.
Well, that can't be right. What if you mostly wanted to play the radio? Don't see a cap-can for the motor. My dark suspicion is that this smoke was already planning to escape, and your playing was the last straw<G>. 60 year old caps tend to smoke for no special reason.
Sounds right to me. It was quite a spectacle. Are those transformers usable in a lower wattage 6v6/5y3 design like a Tweed Harvard? Deluxe?
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Are those transformers usable in a lower wattage 6v6/5y3 design like a Tweed Harvard? Deluxe?
Already forget about reply #2? :icon_biggrin:
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Are those transformers usable in a lower wattage 6v6/5y3 design like a Tweed Harvard? Deluxe?
Already forget about reply #2? :icon_biggrin:
No, didn't forget and I appreciate the suggestions. I'm just trying to understand if these transformers are a drop in replacement for a Harvard/Deluxe, or if there are other considerations? If these were used for a 2x6v6 amp, can they just be swapped into any other 2x6v6 circuit?
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The best use of that Bogen is fix it as is and give it to some old square dance caller.