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Topic: Biasing hybrid Standels... |
Jon Nygren
From:
Wisconsin, USA
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Posted 15 Jul 2011 9:53 am |
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So do any of you guys who have experience with the hybrid standels know how Mr. Crooks intended these sweep tubes to be biased?
Would it be just like a class AB fixed bias Fender- right around 65-70% of max dissapation?
I have mine biased like that right now, as it needed new tubes. Sounds good, but i'm wondering if thats how it was supposed to be from the factory? |
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Mike Bagwell
From:
Greenville, SC, USA
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Posted 16 Jul 2011 5:09 am
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Jon,
Thats the way I biased mine, but just as you, I had second thoughts. So I hauled out my signal generator, dummy load, and Oscope. I did it several times and even had a friend look at the scope and tell me his opinion of when the notch disapeared.
The current draw between the scope method and the shunt 65 to 70% method was very close, within 10%, so Im confident the method you are using will work.
Mike
Last edited by Mike Bagwell on 16 Jul 2011 5:33 am; edited 1 time in total |
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Ken Fox
From:
Nashville GA USA
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Posted 16 Jul 2011 5:15 am
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Sounds like you guys are doing it as right as you can. Here is a copy of the old schematic showing -28 to -30 volts on the bias voltage. Forgot I had that around!
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Jon Nygren
From:
Wisconsin, USA
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Posted 16 Jul 2011 11:38 am
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Awesome, thank you Mike and Ken. That settles it.
I had some mismatched tubes in there, and just replaced them with a closely matched NOS pair. Boy does this thing sound sweet now.
It sounds so nice that i'm thinking of ditching my other tube amps and looking for a little lower wattage 1x12" artist combo or piggyback for the smaller venues. |
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