n_maher Posted March 25, 2010 Report Posted March 25, 2010 Negotiations for time/place to commence shortly. Of course I don't have much to listen to these days but I should be able to provide some interesting sources. Quote
voodoochile Posted March 25, 2010 Author Report Posted March 25, 2010 Interesting sources is an understatement! Sounds good to me. Quote
aerius Posted March 25, 2010 Report Posted March 25, 2010 I do have a half dozen 872-A rectifiers, but I need a filament ransformer the size of a lawnmower to run them. Bummer. I have a couple of those which I found in a surplus store and was planning to use as a giant night light. The local surplus suppliers didn't have a suitable transformer so I ended up using a computer PSU to power the filament. The project didn't get very far since I didn't have a socket for the tube and it was entirely put together with clip leads. Quote
voodoochile Posted March 26, 2010 Author Report Posted March 26, 2010 My RCA book says 7.5A, up to 8A if the V is 5.25. Upshot is only dropping 10v I suppose. 15 amps for a full wave setup? It would make a neat nightlight, but the transformer would be quite a heater. These things are huge... [ATTACH=CONFIG]2929[/ATTACH] Quote
voodoochile Posted March 30, 2010 Author Report Posted March 30, 2010 After more careful measurements I found my input stage's voltage a bit high relative to the output stage, so made some adjustments there. Also had to make an adjustment to my filaments; they weren't floating high enough. It sounds good, and isn't running quite as hot, though still pretty hot. The 12B4As are at 23ma. I want to try some tweaks with the rectifier next, then have another pair of OPTs to compare. Another shot in the dark- Quote
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