biasing

Orange Amps Technical Q&A's

Moderator: bclaire

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ayoldguy1
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Joined: Mon Dec 09, 2002 6:15 am

Post by ayoldguy1 » Thu Dec 26, 2002 5:36 am

Are the AD series amps self-biasing? I need to change my tubes to get rid of some humming- Orange is sending me a complete set of tubes.

bclaire
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Post by bclaire » Thu Dec 26, 2002 3:24 pm

I've never actually heard of a tube amp that was self-biasing. I'd pay the money and bring it to a tech to be sure. It shouldn't be much if you already have the tubes- maybe $25-35.

VintageJon
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Post by VintageJon » Sun Dec 29, 2002 6:42 am

Pricing for any amp work is dependent on the cost of doing business in the city you have it done in- and how complete a job you want.

A complete bias job from me means:
I test the tubes for function and "leaks".
I test the tubes for match- no more than 5mA out of match.
I bias by cross-over distortion then check the plate current
for each tube to insure the match is stabile.
I burn the amp in at max clean power for 1 hour minimum.
I give you a written report on the bias current and power
being generated by the amp.
If you buy the tubes from me I warranty them for the manufactors
warranty duration- 6 months Ruby, 90 days JJ.

I do this for $50 including any resistors or bias circuit
componets that are needs- including building a complete bias
adjustment circuit when needed- WHEN YOU BUY THE TUBES FROM ME.

You have your own tubes:
I do all the above at $50 per hour and the warranty is between whoever you got the tubes from and you. Any other parts required
are billed at extra cost. Of course you can specify less service
for less money if you don't want it exactly right.

Find a good tech. Buy your tubes from him/her. Whatever mark-up
we make on the parts will be offset by work performed and warranty.
We're just trying to make an honest living after all.

Jon Bessent
Tonecraft Amp Repair
Austin TX

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