RE: This is a fixed bias, Class "A" amp?

Posted by PakProtector (A) on July 21, 2016 at 14:35:34

In Reply to: RE: This is a fixed bias, Class "A" amp? posted by FenderLover on July 20, 2016 at 06:58:39:

Please describe this boas supply that is consuming this 19.2 mA? That is a little less than 1k at 15V( but that isn't the right voltage, we're dealing with the -30V supply ), that would be the total supply voltage applied to the top of the voltage divider( hopefully including at least one pot ). IOW, with a pair of 10k pots, one for each tube, we have a total bias supply resistance of 5k, or 6 mA flowing through it, plus the grid current( which will be much less than 6 mA ). 1 mA of grid current flowing through a 50k grid resistor gives us 50V...and that for sure isn't happening.

Please explain where all this current is going.
cheers,
Douglas

Friend, I would not hurt thee for the world...but thou art standing where I am about to shoot.

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Follow Ups Full Thread

Topic - How much current does a -bias voltage need for 6550 tubes - DAK 21:01:41 07/18/16 (22)

RE: How much current does a -bias voltage need for 6550 tubes - hifipaul 19:02:31 07/19/16 (0)

RE: How much current does a -bias voltage need for 6550 tubes - Lee of Omaha 08:40:07 07/19/16 (3)

Bias supply choke - Triode_Kingdom 11:04:58 07/19/16 (2)

RE:I have different value chokes - DAK 11:11:37 07/19/16 (1)

RE:I have different value chokes - Triode_Kingdom 11:35:31 07/19/16 (0)

No easy answer... - Triode_Kingdom 08:26:09 07/19/16 (0)

RE: How much current does a -bias voltage need for 6550 tubes - Michael Samra 21:30:58 07/18/16 (15)

RE:I am talking about current needed for the bias supply - DAK 22:23:31 07/18/16 (14)

Very little if you speak of the power supply - Michael Samra 10:52:45 07/19/16 (0)

Not much - FenderLover 23:04:15 07/18/16 (12)

"few hundreds of mA, max." - Chip647 05:07:44 07/19/16 (11)

RE: My amp is PP class A - DAK 11:24:53 07/19/16 (7)

This is a fixed bias, Class "A" amp? - FenderLover 22:03:06 07/19/16 (6)

RE: This is a fixed bias, Class "A" amp? - PakProtector 03:38:14 07/20/16 (5)

RE: With EL34 I am using -30v for 60ma/tube - DAK 09:34:28 07/20/16 (2)

RE: With EL34 I am using -30v for 60ma/tube - FenderLover 10:00:04 07/20/16 (1)

RE: Thank you for that info. - DAK 14:28:47 07/20/16 (0)

RE: This is a fixed bias, Class "A" amp? - FenderLover 06:58:39 07/20/16 (1)

RE: This is a fixed bias, Class "A" amp? - PakProtector 14:35:34 07/21/16 (0)

RE: "few hundreds of mA, max." - FenderLover 06:51:45 07/19/16 (2)

RE: "few hundreds of mA, max." - Jim McShane 08:02:59 07/19/16 (1)

It is simple - PakProtector 10:52:38 07/19/16 (0)

Follow Ups

RE: This is a fixed bias, Class "A" amp? - PakProtector 14:35:34 07/21/16 (0)

RE: This is a fixed bias, Class "A" amp?

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