JTM45 Reissue cant be biased

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SlyStrat
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Joined: Sat Dec 23, 2006 2:55 pm
Location: Cleveland, Ohio

JTM45 Reissue cant be biased

Post by SlyStrat » Sat Dec 16, 2017 3:02 pm

Cant bias tubes to correct number.
Which resistor needs to change and do I ho up or down?

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neikeel
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Location: Suffolk, England

Re: JTM45 Reissue cant be biased

Post by neikeel » Sat Dec 16, 2017 6:16 pm

On the board there is a resistor in series with the bias pot (47k or 56k typically).

As they bias voltage is negative if you want a more negative voltage you need to raise the value of the resistor (shunt less voltage to ground) or visa versa.
Neil

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