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Vintage threads from the first ten years
newbie homebrew confusion !
 4/9/2003 7:56 PM |
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gazza | newbie homebrew confusion ! hi all, I'm stuck and need some advice. I have built a PP el84 amp fed by a long tail pair using a 12ax7 and two pre stages using a second 12ax7. It's all fairly standard stuff - I'll try and put photo's of it's guts and the schematic I've tried to build. (EZ81 rectifier) OK, I'm using 100K pre anodes 1.5k cathodes, a LPT like a marshall (i think) and i have a shared 130 ohm cathode for the el84's. what do people think of these voltages I'm getting ? b+ to first filter and OT = +284 V. b+ @ EL84s = 273. b+ @ LTP anodes = 244. (too high ?). B+ for preamps = +237V , +236V. B+ at pream anodes = +152, +155V cathodes of the LTP = +55 V (=centre of the 4 resistor star) cathode of the EL84s = +9 V (too high with 130ohm?) cathodes of preamps = +1.25V, +1.2V. how do I work out my anode dissipation on the el84 anodes ? I know its a max of 12W each. HELP ! are these correct or not ? cheers all, Gazza |
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| gazza does anyone have a link to a schema... -- 4/10/2003 12:20 PM gazza It's ALIVE !!!!!! -- 4/14/2003 10:51 AM |