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Bias Recommendations
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casken
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PostPosted: Fri Nov 06, 2009 6:03 am    Post subject: Bias Recommendations Reply with quote Report this post to administrator

I have a Fender Pro Tube Series 1X12 Concert Amp. What is the bias setting recommendation for the Power Tubes? I appreciate any help you could offer.

Casken
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casken
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PostPosted: Fri Nov 06, 2009 7:57 am    Post subject: Reply with quote Report this post to administrator

I am being told by someone on another board that there is not a bias adjustment on the amp. Can anyone confirm that?
Would that mean it is just plug and play?
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atolleter
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PostPosted: Fri Nov 06, 2009 11:03 am    Post subject: Reply with quote Report this post to administrator

I dont think it is a cathode bias. It is fixed which will require a re bias. Let's see what others have to say.
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63supro
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PostPosted: Fri Nov 06, 2009 11:19 am    Post subject: Reply with quote Report this post to administrator

It's fixed bias. I'm only finding the 2x12, but I'm sure the amp is the same.

http://www.ampwares.com/amp.asp?id=52
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casken
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PostPosted: Fri Nov 06, 2009 12:39 pm    Post subject: Reply with quote Report this post to administrator

I was pretty sure it was a fixed bias...what is the recommended setting for the power tubes? THis will be my first run at doing it myself.
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aclempoppi
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PostPosted: Fri Nov 06, 2009 6:34 pm    Post subject: Reply with quote Report this post to administrator

Casken, unfortunately there is no set number. There is only a safe operating range for tubes. One method is to adjust the bias by ear until you find the sound you like, then check that it's in the safe range. You can find a "bias calculator" on various sites, one being:www.tedweber.com go to the bias rite, and scroll down to "bias calculator." After looking at the schematic, it appears there is a seperate board with bias and balance controls.(power amp schem, coordinates 1,A-B) On some '90s amps these boards were an option, not sure about yours. My experience is mostly with the older amps. I'm afraid the PDF files are not clear enough for these old eyes, but if you can scour the layout you should find the circuit. ART
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casken
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PostPosted: Sat Nov 07, 2009 5:31 am    Post subject: Reply with quote Report this post to administrator

Art, thanks for the info. The schematic you speak of...where did you find it? I bought the amp used and have no ppw with it. I appreciate your time.

Casken
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casken
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PostPosted: Sat Nov 07, 2009 5:38 am    Post subject: Reply with quote Report this post to administrator

Art...nevermind I found the schematic...thank you sir.
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