Quote:
Originally Posted by sjhusting
I'll bet there's no mains transformer in there.
Let's see 50 + 12 +12 + 12 + 12 = 98 (volts) for the heaters, there is proably a big resistor in the heater chain, too.
Some older 'cheap' amps (Silvertone and similar) used series heater tubes. The heater voltages add up to line voltage, with anything missing being burned by a resistor. Saved the cost of a mains transformer. Can put line voltage on the chassis, though, and is risky. Also violates current code, certainly, and for good reason.
The triode part of the 12sq7 has a mu of 100, like a 12ax7. I guess you could use that for something, but you'll have to wire up a 12.6V heater supply. I've got a bunch of those, but never got around to using them for anything. I just use 6SL7 when I want to go octal.
The heptode and 6sk7 are radio tubes. You can't use the heptode for anything. You could try the 6sk7 as a pentode input (preamp) stage, like a ef86, that might be interesting. I have a bunch of those, too, hmm ....
The output transformer will probably have a 3-4K primary, so you could use it to build a nice little SE 6L6 amp. A 50L6 will put out 4-5 watts, it's not likely the transformer will take much more than that.
If it's in good shape, it seems a shame to rip it apart for a handfull of octal sockets and a small transformer.
just my 2 cents
steven
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Thanks Steven!!!!! As you thought there is no power transformer, but there is huge cap in the wiring so I think you nailed it.
I was actually taking stock on the radio as a whole, and think I will see if I can get the station selector working again. Currently it gets lots of static, but I think I can get it working again. Failing that I will leave it intack. Just seems like a bad idea to ruin a potential hairloom....
