Red Fuzz/JFet Question

[Chris R]

I'm looking at the Red Fuzz Schem on GGG

http://www.generalguitargadgets.com/v2/diagrams/red_fuzz_sc.gif

Everything looks perty standard.. ic w/ feedback loop etc... but whats that jfet doing there ?

maybe if you all could point me somewhere that explains generally what a jfet does to an audio circuit.. that would help too.

Thanks

C

[Jay Doyle]

In this case the JFET is buffering the output of the tone control so that it doesn't load down the volume control. The JFET takes the signal at it's gate and reproduces it in the same phase, with just a little lost volume (not enough to hear really) at a higher current to give it a lower impedance when it goes into the volume control. Basically, it seperates the effects of the tone control and the level control.

Some good basic JFET application notes:

http://www.vishay.com/fets-small-signal/ssfanp/

Hope this Helps,

Jay

[Chris R]

wow.. thats some good reading.. seams like fets are very versitile..

thanks for the explanation jay.. it helped alot.

C