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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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Tube DIY Asylum Do It Yourself (DIY) paradise for tube and SET project builders. |
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In Reply to: I think I wait for Allen Wright's PowerAmp CookBook... posted by Allen Wright on December 21, 2003 at 04:53:40:
I'm using a 2A3 diff amp output stage in a stereo amp, and it does indeed sound great. I too thank Douglas for his CCS guidance and for answering all my dumb questions. (I am too cheap to spring for DN2540's in lots of 50 though, so I'm using bipolar CCS's).I'm using fixed bias for the 2A3's, plate at 250V, bias at 45V, current approx. 60 ma per side. The CCS is a C4S I made from scratch; NPN cascode with LED bias. For the driver stage I'm using a diff pair of 5687's, battery bias, 180V plate, 7V bias, approx 25 ma a side, C4S. Line stage is 12SN7, diff amp, DC filaments, plate voltage 250V, 9V battery bias, 10 ma per side, C4S. Right now I'm using .22 uf Panasonic film/foil coupling caps (they are shaped like orange drops) and an Edcor 10K:10K IT for the power stage. (During Xmas break I'm going to switch to cap coupling to see what difference it makes. I might but a pair of 1660s IT's but for $180 I want to try cap coupling first.) Speakers are Pioneer 8" full range. These are roughly 97 db speakers, and I hear no hum, no buzz, from this set-up, with my ear against the speakers. (Balance and CMRR baby!)
PS for PA is a One Electron BFTB with a parallel 4H> 200uf> 1.5H> 200uf chain for each channel, it's a stereo amp. Rect is a pair of 6CJ3's.
Line amp PS is a CLCLC in a separate box.For my next trick, I'm going to build a pair of 200 liter/30hz afterburners. Right now I am fighting WAF (have been since last spring) but I think Xmas is going to save me (all I want is a pair of Beta 12LT's, some lacquer, and permission to build two big boxes from oak plywood.)
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Follow Ups
- They Do Indeed Sound Wonderful...... - MikeT 12/21/0305:55:09 12/21/03 (0)
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