In Reply to: Thomas stereo organ amplifier 6973 to 6cz5 conversion posted by joshie on January 14, 2022 at 19:21:11:
The RCA data sheet states 500K maximum for fixed bias, not 100K. In any event, when fixed bias is used, it's assumed the grid resistor will be connected to a low resistance node of the negative bias supply, not ground.
About dropping the anode supply, you might want to consider a small string of Zener diodes. Adding series resistance will degrade supply regulation.
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Follow Ups
- RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion - Triode_Kingdom 01/14/2221:16:43 01/14/22 (18)
- RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion - joshie 04:33:21 01/15/22 (17)
- can you post a schematic? - Tre' 16:43:17 01/15/22 (5)
- This might be close. - Tre' 06:32:53 01/16/22 (4)
- RE: This might be close. - joshie 10:12:32 01/16/22 (3)
- RE: This might be close. - Tom Bavis 11:08:47 01/16/22 (2)
- RE: This might be close. - joshie 12:12:50 01/16/22 (1)
- RE: This might be close. - joshie 13:33:09 01/16/22 (0)
- RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion - Triode_Kingdom 16:14:33 01/15/22 (9)
- RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion - Paul Barker 03:34:33 01/16/22 (8)
- RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion - Tre' 06:29:48 01/16/22 (7)
- Agree - "grid resistor" - but then again... - Triode_Kingdom 11:28:23 01/16/22 (6)
- RE: Agree - "grid resistor" - but then again... - Paul Barker 23:14:30 01/16/22 (5)
- That's called "dumbing down" - Triode_Kingdom 10:11:12 01/18/22 (4)
- RE: That's called "dumbing down" - joshie 07:54:55 01/22/22 (3)
- RE: That's called "dumbing down" - joshie 08:24:03 01/22/22 (2)
- RE: That's called "dumbing down" - Tre' 16:35:27 01/22/22 (1)
- RE: That's called "dumbing down" - joshie 16:35:35 01/29/22 (0)
- RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion - Tom Bavis 14:24:05 01/15/22 (0)