Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
In Reply to: insufficient range on bias pot scott 299b posted by thermionic emitter on July 12, 2016 at 22:39:37:
As I learned with my Scott 299A, the schematic bias voltage is approx and it needs to be adjusted for the actual tubes used. But you'd think the -11 would be on the low side seeing that they did show -15 volts on the schematic.
You didn't say how you derived at the current reading. If you took a voltage reading and converted it to ma, is it possible you forget that the cathode resistor per output pair shown in the schematic is 18 OHM and not 10 ohm?
The other question would be: how did you balance the output pair?
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- RE: insufficient range on bias pot scott 299b - DaveV 19:06:01 07/13/16 (16)
- RE: insufficient range on bias pot scott 299b - thermionic emitter 19:26:19 07/13/16 (15)
- RE: insufficient range on bias pot scott 299b - Michael Samra 14:41:12 07/14/16 (0)
- There is an easier way to do this. - Michael Samra 19:52:39 07/13/16 (13)
- RE: There is an easier way to do this. - DaveV 20:39:24 07/13/16 (12)
- RE: There is an easier way to do this. - thermionic emitter 22:10:36 07/13/16 (11)
- RE: There is an easier way to do this. - DaveV 01:03:57 07/14/16 (0)
- Have you tried a know, good set of EL84? - FenderLover 23:48:34 07/13/16 (9)
- RE: Have you tried a know, good set of EL84? - Eli Duttman 10:33:08 07/14/16 (1)
- I saying trying another set of tubes... - FenderLover 18:15:56 07/14/16 (0)
- RE: Have you tried a know, good set of EL84? - thermionic emitter 09:12:34 07/14/16 (6)
- RE: Have you tried a know, good set of EL84? - Eli Duttman 10:41:06 07/14/16 (5)
- RE: Have you tried a know, good set of EL84? - Jim McShane 11:19:22 07/14/16 (4)
- Server Not Found - Triode_Kingdom 12:01:37 07/14/16 (3)
- Got it - Nice Article Jim! (nt) - Triode_Kingdom 13:27:12 07/15/16 (0)
- RE: Server Not Found - Jim McShane 17:57:13 07/14/16 (0)
- RE: Server Not Found - Eli Duttman 12:52:10 07/14/16 (0)