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Half-Power Switch on Cathode-Biased P-P Amp

12/30/2005 3:26 PM
Jeff Miller
Half-Power Switch on Cathode-Biased P-P Amp
I'm thinking of building the Weber 5E3x2 amp (take your basic 5E3, and double the power tubes and the speakers in the cabinet).  
I'm thinking of wiring in a half-power switch, and I am curious what lifting the input grid to 2 of the 4 6V6's (one from each pair) would work without it jacking something up.  
12/30/2005 8:33 PM
Bob G.
While not using the method you describe, I added a half power switch on an early mod of my Peavey Classic 30. This amp is originally a 4xEL84 fixed bias amp but I also added a switch to convert it to cathode bias and added a 2nd switch to make it half power by removing the cathode connection to two of the four tubes. In this method you need to be sure to change the cathode resistance by doubling it when switching to half power.
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12/31/2005 6:20 AM

I don't know why that wouldn't work, just make sure to have some sort of resistor to ground on the tube side of that switch - no floating grids.
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