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previous: Bruce No, not much.I just thought it ... -- 11/28/2000 6:30 AM View Thread

Re: Bedrock MV

11/28/2000 10:57 AM
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Re: Bedrock MV
If you have "the wipers facing the output tubes" then the impedance seen by the PI coupling caps is constant, and equal to the pot value. Also, you'll need coupling caps from the master to the output tubes, because it's a bad idea to bias them from the wipers.  
 
If you have "the wipers facing the PI" then the impedance seen by the PI coupling caps will go down as the master is turned down, and so the bass corner frequency will go up. Also the impedance in series with the output tubes' grid capacitance increases at low master settings. This means less bass and less highs at low master settings. It's safer to bias the output tubes from the pots because it doesn't depend on the wipers, so you can use only two coupling caps instead of four.