J201 Buffer. Do I need to bias?

[melveyr]

Hey ya'all,

I was going to combine some of the muffin crumbs and J201 buffer PCB to make my own frankenstein creation. I have done other builds with J201s and used the trim pots to help get it sounding right. Looking at the schematic for the buffer it doesn't appear to have trim pots:

https://docs.pedalpcb.com/project/Buffer-TH.pdf

Do I not need to worry about trim pots because it doesn't matter in the buffer configuration? I am still learning about electronics.

 

[Robert]

Nope, no bias adjustments are required.

 

[melveyr]

Nope, no bias adjustments are required.

Thanks Robert. I am going to use this J201 as an input buffer, feeding a who bunch of different muff stages. Thanks for making those!

 

[mdc]

You might want to socket the FET and try a few different options out. If the source voltage is low (below 1V) you might notice some distortion with higher output pickups. I think "ideally" you want source voltage to be around 1/2 supply, but given that it's feeding a distortion pedal you might not ever notice the front end distorting.

 

[melveyr]

You might want to socket the FET and try a few different options out. If the source voltage is low (below 1V) you might notice some distortion with higher output pickups. I think "ideally" you want source voltage to be around 1/2 supply, but given that it's feeding a distortion pedal you might not ever notice the front end distorting.

Good point. I will just follow the schematic values for resistors but socket the JFET to make sure I get one that matches the circuit to function well.