Eliminating RobRob's Hum balance ckt.

[JustMike]

 First off, I started with an old PT that I used to have in a Deluxe that I built and it worked fine. I forgot what the voltages were, but it served me well for a year or two. I got bored with it and decided to drop in a board I made for a 2204. The bias voltage is tapped off the main PT secondaries and my B+ at the first filter cap is 437 VDC. A little high, but serviceable (yes?).


 Rob's ckt shows a 470Ω but then after the reverse rectifier ckt it goes thru a hum balance ckt (Which I think is always going to be at least 10kΩ) and a max bias R of 7.5kΩ before the 50k pot.


So, my question is; If I eliminate the hum balance ckt. do I need a resistor in it's place? This would be the 15k that Marshall shows between the 2 10u caps? And I believe I can eliminate the following 47k that's in series with it as well?

[sluckey]

Just rip out the entire bias circuit and build a new circuit based on Hoffman's Plexi50 circuit. R36 is the bias range resistor. You may need to slightly change the value to provide the desired bias voltage based on your PT.

     https://el34world.com/Hoffman/files/Hoffman_Plexi50.pdf

This circuit is the same as the 2204 circuit.