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previous: Cliff Is is safe to use the negative side... -- 7/25/2000 3:39 AM View Thread

Re: Bias supply ??

7/26/2000 12:49 AM
Brian
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Re: Bias supply ??
Do you mean the diodes off your HV winding on your PT?  
 
NO.  
 
There is AC on the anodes of your recifier diodes.  
 
The bias supply should either come from a separate tap, or just run a diode backwards (cathode towards the transformer) off of one of the two HV taps.  
 
Run that to a filter cap, and then to a pot to ground. Well, you might want to have a resistor in series with the pot if your winding is too hot. You never need -250V of bias, and your 0.5W pot may not like that :)  
 
Fender usually used 50uF for two or 100uF for four 6L6, and the pot was 10K. In your case you will probably have a lot more than 50V available though using the HV tap.  
 
BT