Re: Erratic bias measurements with 2A3 and 300b in my AES SE-1

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In Reply to: Erratic bias measurements with 2A3 and 300b in my AES SE-1 posted by Darryl on December 27, 2002 at 12:48:42:

Darryl:
Sorry about the response time. It is best to use a dedicated ammeter with a range of 0 to 500mA when setting the bias of a SE-1. Do use your multimeter to check the grid bias voltage of the two 2A3's--this is pin 3 and should read around -60vdc to -65vdc for the proper 2A3 plate current to flow. Remember, this amp has a "fixed bias" output stage and needs an induced negative bias voltage on the 2A3 grid to work correctly. If you get a voltage reading on the grid less than negative (-)60vdc, then check the bias voltage subcircuit. Also, run the amp in a darkened room and see if the plates glow-not a good thing. Up to a point, high plate current thru a Sovtek 2A3 will sound ok, but around the 200mA point the sound of the amp will become hard and brittle. Try and avoid operating the amp under that type of condition. I like to run Sovtek 2A3's around 50mA with about 275vdc on the plate. SE-1's are great little amps, and imho sound the best running 2A3's. Have fun and later.
don

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Follow Ups Full Thread

Topic - Erratic bias measurements with 2A3 and 300b in my AES SE-1 - Darryl 12:48:42 12/27/02 (2)

Re: Erratic bias measurements with 2A3 and 300b in my AES SE-1 - geoduck 14:06:28 12/28/02 (0)

Re: Erratic bias measurements with 2A3 and 300b in my AES SE-1 - steven oda 18:36:57 12/27/02 (0)

Follow Ups

Re: Erratic bias measurements with 2A3 and 300b in my AES SE-1 - geoduck 14:06:28 12/28/02 (0)

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