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70.230.178.0
Call me crazy but I love these, just for the age of them, Built to Last!
Have Fun!
Willie
Follow Ups:
Willie,The flea bay description mentions a field coil speaker, which is correct for 1936. Was the "usual" method employing the field coil as a 2nd inductor in the B+ PSU used?
Eli D.
just curious, . Do these amps hum with all those DHTs in the chain (SE -> PP pair) and (I presume) A/C heating ?
These are really interesting amps, I've completely rebuilt 2 of them.
Yes all DHT, but the (2) type 30's and the first 45 are DC heated.
The IT is a real quality IT. I replaced the OPT"s with Electra-Prints. They run Class B and can do near 8 watts and sound pretty good.
I also have a 661 I completely gutted and made a 417A IT coupled PP45 Stereo amp,one of my favorites.
Willie,How was the DC filament supply obtained? Was a Copper oxide rectifier used?
With DC on the small signal filaments and cancellation in the PP O/P trafo, hum should not be a problem in that amp.
Eli D.
The DC is derived from the B+ and resistors. Simple and quite
affective! For a 1936 all DHT amp tube amp, they are pretty quiet!
I picked up one of these along with a bunch of other old tube radio hulks years ago at a Salvation Army in Marysville WA. The amp had three Cunningham CX 345 tubes which all tested fine. The wiring in the amp looks very scary. It is far more of a project than I want to take on.
Yeah The power supply section is compliated,they are not a simple. But with little patience they can be rebuilt and sound pretty good.
Have fun!
Willie
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