10-21-2010, 07:22 AM
Hi Glenn and welcome!
Well what you will have to do is some reverse engineering. Pull out your handy tube manual and add up all the filament current of your 6V tubes and pilot lamps. I came on with 4.1amps (@6.3V) The 80 tube takes 5v 2amps. As for the HV current wise the 80's max output is 120ma. Generally I figure about 10ma per tube except for the output stage. Push-pull 42's could haul down as much as 80ma. With that calculation it come to about 160ma but that is is more that the 80 tube can put out. Granted at 245v the 42's aren't running at full tilt (about 75% of full tilt). HV Needs to make 245vdc+about 15v bias. Total is 260vdc. There will be a 50v loss per plate across the 80 when the ac is rectified and turn into dc. The 80 tube is a full wave rectifier Which means that it will only will rectifying one half or the hv winding at a time so you will need the hv winding that is twice voltage. So bottom line what you are looking for is a transformer that can provide 6.3v @ 5A, 5v2A, and 310vac-0-310vac or 620vac end to end @120MA. The hv winding isn't super critical if you find something that is within 30v or so it should be fine.
Good luck with your project! From the diagram is looks to be a nice set with lots of audio.
Terry
Well what you will have to do is some reverse engineering. Pull out your handy tube manual and add up all the filament current of your 6V tubes and pilot lamps. I came on with 4.1amps (@6.3V) The 80 tube takes 5v 2amps. As for the HV current wise the 80's max output is 120ma. Generally I figure about 10ma per tube except for the output stage. Push-pull 42's could haul down as much as 80ma. With that calculation it come to about 160ma but that is is more that the 80 tube can put out. Granted at 245v the 42's aren't running at full tilt (about 75% of full tilt). HV Needs to make 245vdc+about 15v bias. Total is 260vdc. There will be a 50v loss per plate across the 80 when the ac is rectified and turn into dc. The 80 tube is a full wave rectifier Which means that it will only will rectifying one half or the hv winding at a time so you will need the hv winding that is twice voltage. So bottom line what you are looking for is a transformer that can provide 6.3v @ 5A, 5v2A, and 310vac-0-310vac or 620vac end to end @120MA. The hv winding isn't super critical if you find something that is within 30v or so it should be fine.
Good luck with your project! From the diagram is looks to be a nice set with lots of audio.
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!
Terry
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