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previous: Major Pain Don,Would this be adding a resi... -- 11/14/2003 3:43 PM View Thread

Re: Best way to reduce Filament voltage?

11/16/2003 1:32 PM
Don Symes
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Re: Best way to reduce Filament voltage?
Well, you have 3*.3A for the 12ax7s ==> .9A and 2*.9A for the 6L6s ==> 1.8A so total heater current is 2.7A.  
 
Now, you want to drop 7.5 - 6.3 = 1.2V total, or .6V per resistor (one in each side of the heater pair), so  
 
.6V/1.8A = 0.3 ohms and .6V*1.8A = 1.08W.  
 
Grab 3 1-ohm 1/2-watt resistors per side and put 'em in parallel, then put them in series with the heater wires.  
 
That ought'a do it.

 
Replies:
Major Pain Re: ? -- 11/17/2003 2:59 AM