On September 10, 2014 at 00:32, Ernie Gilman said...
highfigh,
that's all great, and great stuff.
I found a reference to the 80 at
[Link: radiomuseum.org], which says it was introduced in 1926.
I'd thought the 80 was older than the thirties, based on it being in my favorite AM radio, a Philco TRF with four stages of RF amplification and WOW a tuning capacitor that tracked. I got WLS in Chicago on that, in Los Angeles, with a 20 foot length of wire and a ground. It went south slowly, then quit. ALL of the filter capacitors and cathode bias capacitors were in one unlabeled tin box. It was too late to try to work out what the capacitance values were and I couldn't find a Sams on it. Oh, well.
I forgot that there were five pin tubes, too, that pretty much HAD to be triodes. Two pins for filament, one each for plate, grid and cathode. Simple.
Thanks. This is fun.
Quite a few 5 pin rectifiers, too. 5U4, 5AR4/GZ34, 5Y3, 5R5, 5V4, etc.
Lots of contradictory info out there.
Re: your Philco- you could have looked at the tube manuals for rectifier info or a tube circuits book from Western Electric, RCA, ATT, etc. I doubt they used a proprietary circuit for much of anything and if it has/had a label inside like this link, it would have been easy enough. That is, if the internet was available. If you still have it, it shouldn't be hard to do. 30uF was common, since the plate voltages were lower than in later models. The bypass caps were probably 25uF/25VDC or 25uF/50VDC unless it was for the input tube and lower frequencies were desired. My Fender Bassman has a 250uF/6VDC bypass cap for the input.
