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Vintage threads from the first ten years
Power Supply for Preamp
 3/27/2000 7:51 AM |
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Dominik | Power Supply for Preamp Hi, I am in need of some sound advice on power supplies. I have decided to build a two channel preamp (modeled after the Humble 97 and 70s Humble). I would like to include the Humble-a-tor as well. I have a 340 -0- 340 (80 mA), 250 -0- 250 (80 mA) , 6,3 2.5 A power tranny. I want to use 4 1N4007 diodes in a "graetz-bridge" (full wave rectify...). Since I don´t have a choke and prob. won´t need one in a preamp, I figured that the filter section after the rectifier would look like this: 2* 100 µF caps ins series with two 100 k resistors paralleled to assure voltage splitting between both caps. After this, there would be a resistor which value is not quite clear to me (5k??). I need 346 V, 321 V, 306 V, 303 V (or something thereabouts). My question is, what voltage will I get if I rectify the 250 VAC? 319 VDC?? (250V times 1.1??) Is there information out there considering such things? I would need a cap (16 µF 450 V) and a resistor for every stage to isolate them. Does anyone know what voltages should be present on the anodes of the humble-a-tor tube??? I would be very thankful for any advice on this. Best Regards, Rookie |
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| Replies: |
| Bruce Your preamp will draw very little c... -- 3/27/2000 4:53 PM Dominik Hi Bruce, |