Dr. Boogey trimmers

[MetalUpYerEye]

Hi I know the Dr. Boogey has several 100k trimpots in it, would it be ok to replace them with fixed resistors? What would be the outcome of fixed vs. trimpots? What values would yield what changes?

[dano12]

I'd stick with the trimmers if possible. They allow you set the operating voltage for the JFETs. Also, you may find that J201s in each slot is a bit too gainy and can lead to noise and squealing. Lots of folks replace one or more of the J201s with MPF102s. Another reason to use trimpots instead of fixed resistors.

[petemoore]

  As long as the Jfet is biased, it doesn't care what provides the resistances.
  One method is just to socket where the resistor goes, insert your pot via wires to find the R value which biases the Jfet, measure [without disturbing the setting] the pot, find or build a fixed resistor, insert in socket.
  This way should you choose to swap Jfets or have a bias issue, the socket will be there.
  Trimpots have the advantage of making it easier to swap 'n bias transistors, but may have a disadvantage fixed resistors don't have, that'd be pot troubles...