Bias setting question

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sergio
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Bias setting question

Post by sergio »

When set the Bias:

1)The P.I. tube must be connected?

2)The P.I input must be wired to ground?

3)On secondary of OT must be insert a load?

Thanks
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markmalin
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Re: Bias setting question

Post by markmalin »

sergio wrote:When set the Bias:

1)The P.I. tube must be connected?

2)The P.I input must be wired to ground?

3)On secondary of OT must be insert a load?

Thanks
Ciao Sergio. Come va?

If you are talking about setting the bias on the power tubes, you need everything wired up and all the tubes plugged in. Someone may have a suggestion for where to set the bias pot initially when you power up the amp for the first time, but you need all the tubes in their sockets, and you need a load on the output tranformer (for example your speaker). Then connect your DVM to the test points and read in milivolts and use that reading as your bias current.

Correct me if I'm wrong, guys.

Mark.
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Bob-I
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Re: Bias setting question

Post by Bob-I »

First off, it's not that critical. Get the amp up and running, then adjust the bias to about 33ma. From there adjust by ear. Anything from about 20ma to 50ma is safe, but about 33ma will usually sound best for 6L6's.
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sergio
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Re: Bias setting question

Post by sergio »

Thanks boys , yes , I've put a speaker on the OT and the 6L6 into the sockets.
I have regulated the bias at 34mA .

Now I'll go on with the wiring.

Thanks very much for your helps.

Sergio
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