• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

ground of DC bias supply

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Yes, you just connect positive to the ground. One thing to note, bias supply's are usually just a couple of RC filters but with the resistors on the bias supply's ground (which will be - Vcc) and the caps positive go to the main ground.

If you use one of those small brdge rectifiers, and a couple of 100 - 470u caps with 680r - 1k ish resistors that should filter the bias supply well and leave it ripple free. Roll off is found by the usual 1/(2 x pi x f x R or C )

It's also a good idea to make the bias adjustable using a pot, but make sure you use a resistor on one leg so the bias cannot go to 0v, it has to be foolproof.

There is some good info on bias supply's for valve/tube amps at Valve Wizard and Elliott Sound Products site.

Andy.
 
Here's an example of a bias supply.
 

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