But then again, Anatech did get just about anything else besides tubes 
http://www.diyaudio.com/forums/attachment.php?s=&postid=1334054&stamp=1193281362
Magura
http://www.diyaudio.com/forums/attachment.php?s=&postid=1334054&stamp=1193281362
Magura
carpenter said:
carpenter said:
carpenter said:... Nelson had a 0.5ohm resistor in the CCS. He runs 3 volts across it which yields 6 amps. Is this what I do to calculate the amperage available to the FETs in the F4?.
Carpenter, P1 adjusts the TL431 (shunt regulator) voltage. It is across the gates of the upper and lower FETs. It takes about 4V (+or-) to turn one of these FETs on to a current of about an amp (+or-). So, 4V on the bottom FET gate and 4V on the top FET gate is necessary to get some current flow through a (or all the) complementary pair(s). Therfore, the TL431 is regulating at about 8V. In this circuit the current through an N Channel device also flows through it's complementary P Channel device. Measureing the voltage across the source resistor will indicate the current through it
You can set the "Bias Current" anywhere you want by monitoring the voltage at the source resistors while changing the TL431 set point with P1. When the TL431 is set a little higher, the upper gate to lower gate voltage will go up and so will the bias current (and voltage across the source Rs). Set the TL431 for a little less voltage and and the bias current will go down... I realize many responded already, and no one was wrong with there comments. I just did not see where anyone actually said the voltage across the N and P ch gates sets the output bias current
vitalstates said:
I'm a bit confused - what amp have you guys been building?
When I made my F4, the service manual said 250mV which corresponds to roughly 0.5A per device - has this changed since?
Running at less than 1.5A combined will surely give you distorded music - especially into 4ohm speakers.