In Reply to: RE: Kit1 Anode Voltage posted by Frank E on October 5, 2007 at 13:10:17:
Thanks Frank. See my other post for a full resolution of the problem, comments welcome.
The dropper resistor (200R) is on the leg of the rectifier, before the choke. It's dissipating approx 4W, so I've used 4 x 5W Kiwame carbon film in parallel. We (audio engineer friend and I) considered other solutions (removing the twin 47uF caps to make it choke-driven, droppers on the twin legs to the O/P Tx) but Brian's suggestion seemed simplest and has worked out that way.
I've changed the cathode resistor to 1k2 and now have exactly 60mA on the WE300B. The rest of the circuit is in spec, the anode voltage to the 5687 is a little high, about 4% up on spec. I'll live with that for now but may change R5/R7 to drop it.
The sound is WAY better. Big change once the transformer was sorted out, but another big leap getting once it was at 60mA.
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Follow Ups
- RE: Kit1 Anode Voltage - RhythMick 03:19:51 10/09/07 (2)
- RE: Kit1 Anode Voltage - Frank E 22:06:45 10/11/07 (1)
- RE: Kit1 Anode Voltage - RhythMick 13:44:49 12/02/07 (0)