In Reply to: Re: Back to the Drawing Board.... posted by Vinnie on December 26, 2004 at 14:33:00:
Aaaaaahhhh... You're using a 1000 ohm/25W resistor between the filament CT and ground, along with -130 volts on the grid? If so, in effect you're "double-biasing" the 845. You're running the tube way down into cut-off, like Class C region :-). Remove the 1K resistor and ground the 10VAC center tap. Set the grid voltage to about -110. That should put you at between 60-80mA. Good enough for testing purposes. You really want 10 ohms/2 watts from CT to ground, and measure .8 volts to ground for 80mA.
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Follow Ups
- Re: Back to the Drawing Board.... - groverg 14:44:30 12/26/04 (17)
- Re: Back to the Drawing Board.... - Vinnie 15:24:54 12/26/04 (13)
- Re: Sheeesh! - Vinnie 16:29:53 12/26/04 (0)
- Looks like we got a preamp problem... - Vinnie 16:12:24 12/26/04 (11)
- Re: Looks like we got a preamp problem... - groverg 17:21:28 12/26/04 (10)
- Re: Looks like we got a preamp problem... - Vinnie 18:39:56 12/26/04 (4)
- Re: Looks like we got a preamp problem... - groverg 20:06:47 12/26/04 (3)
- Re: Looks like we got a preamp problem... - Vinnie 05:51:55 12/27/04 (2)
- Re: Looks like we got a preamp problem... - groverg 09:23:56 12/27/04 (1)
- Re: Looks like we got a preamp problem... - Vinnie 10:38:30 12/27/04 (0)
- Re: Looks like we got a preamp problem... - groverg 17:25:21 12/26/04 (4)
- Re: Looks like we DON"T have a preamp problem... - Vinnie 11:01:36 12/27/04 (2)
- Re: Looks like we DON"T have a preamp problem... - groverg 11:10:55 12/27/04 (1)
- Re: Looks like we DON"T have a preamp problem... - Vinnie 13:58:53 12/28/04 (0)
- Re: Looks like we got a preamp problem... - Vinnie 17:42:48 12/26/04 (0)
- And... - groverg 14:46:20 12/26/04 (2)
- Re: And... - Vinnie 15:29:54 12/26/04 (1)
- Re: And... - groverg 17:24:14 12/26/04 (0)