AB763 Bias too cold resistor swap

[joesatch]

In the pic below there are (2) resistors. A 470ohm and a 27k. The common suggestion is to lower the value of the 27k to around 15k to 22k.  I was getting ready to do that when i came across someone recommending to change the 470ohm. Why do that one and what do i change it to? Max setting on my pot gets me to 32ma on these 6L6's. My bias tap is pretty high 66v so this is why i need to change the resistor

[sluckey]

Either lowering the value of the 27K or increasing the value of the 470Ω will increase your tube current. I prefer to change the 470Ω resistor. Hoffman even calls this resistor the "Bias Range" resistor on all his AB763 amps. I would increase to 1K and re-evaluate. Increase/decrease again if necessary.

It would be very useful if you tell us what the range of negative voltage on pin 5 of the 6L6s. A range of -45 to -60 is usually good enough to make most AB763 6L6s happy.

Look at this for reference...

     https://el34world.com/Hoffman/files/Hoffman_AB763_2.pdf