Found this vintage newcomb record player that had a tube amp inside. I decided to pull the amp out to investigate its potential. I haven't powered it up. I was thinking this would be my first restoration. I build my own passive crossovers so I'm thinking this would be the next step for me. I'm aware of the dangers of tube gear(high voltage). Does this look like a good candidate for a great sounding tube amp. How would it compare to the likes of fisher and Harman kardon?
There is an identical unit for sale a few hours away, I was thinking of making mono blocks from the pair. Maybe removing a lot of the tone controls, volume, making them just straight power amps.
There is an identical unit for sale a few hours away, I was thinking of making mono blocks from the pair. Maybe removing a lot of the tone controls, volume, making them just straight power amps.
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It's not going to be Hi Fi IMO even as dual monos...but a great way to learn hands-on about tube audio...as a stepping stone
The "iron" is not puny. That's a good sign.
Getting rid of the signal processing circuitry is a good idea. However, some attenuation of the I/P signal might be needed, as quite a bit of gain is realized by the pentode voltage amplifier. That gain is needed to compensate for the OEM tone control losses.
Sheet metal "surgery" that removes all of the front panel is a possibility. Use some sheet aluminum to obtain a simple rectangular appearance.
FWIW, I'd change the signal topology to use DC coupling between the voltage amplifier and "concertina" phase splitter. That reduces the total phase shift, which improves stability.
Switching the rectifier to a 5AR4, which raises the B+ rail voltage, and regulating 6V6 screen grid B+ is another thing to mull over. Placing a 0A2 in the 7 pin mini socket and wiring the gas discharge regulator tube in series with a Zener diode would provide the regulated g2 B+. Maximum open linearity from full pentode mode is realized by regulating g2 B+.
Getting rid of the signal processing circuitry is a good idea. However, some attenuation of the I/P signal might be needed, as quite a bit of gain is realized by the pentode voltage amplifier. That gain is needed to compensate for the OEM tone control losses.
Sheet metal "surgery" that removes all of the front panel is a possibility. Use some sheet aluminum to obtain a simple rectangular appearance.
FWIW, I'd change the signal topology to use DC coupling between the voltage amplifier and "concertina" phase splitter. That reduces the total phase shift, which improves stability.
Switching the rectifier to a 5AR4, which raises the B+ rail voltage, and regulating 6V6 screen grid B+ is another thing to mull over. Placing a 0A2 in the 7 pin mini socket and wiring the gas discharge regulator tube in series with a Zener diode would provide the regulated g2 B+. Maximum open linearity from full pentode mode is realized by regulating g2 B+.
If you knew someone that needed a guitar amp then that would be a great candidate for some simple modifications to make it handle '7' on the volume pots, and give room for some modified tone controls. It would certainly give you a learning curve to introduce basic safety, stress, and overdrive relief features.
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Vacuum Tube Valley Issue 10 - special edition on the 6v6 says that there were a lot of cheap kits and dodgy amps around back then but that Newcomb was pretty good (especially the A-127) and some of their stuff is pretty rare so maybe tread carefully before you rip this one apart with chops and changes?
That might be so...but this example ain't one of those...a hopped up Califone, but that's about it, in this case.
