Designed by Don Tillman, this guitar pre-amp circuit design is dedicated for people who don’t like op-amps. This circuit is a discrete JFET pre-amp design, use 2N5457 as the main component. It has low noise, low distortion, low feedback, overloads gracefully, is small, etc.
Overall gain is 3db (2X) or so. It uses about 1/2 ma, so a 9V battery will last a long time. It is possible to add a high boost switch in case you like by having it shunt the 2.2k resistor with a 0.05uF cap (or other value; smaller cap = boosts only higher frequencies, as well as the reverse). You may simply placed in a 10uF cap across the 2.2k resistor in order to up the gain. You don’t like pre-amp circuit with op-amps..? then, just tryto build this circuit. 
No. 1 — May 16th, 2011 at 2:35 am
Dear Don Tillman.
Thank you for very simple guitar Pre-Amp circuit serving . It is very use full for new hand or new hobbyist.When I am make that time some problem faced and I think share with you. You are not shown capacitor polarity side in the circuit and if I change this transistor ,it is possible or not,if possible what number transistor I am use.Please assist me.I am waiting for your valuable concern.
Thanks
Jahir
From Bangladesh
No. 2 — May 16th, 2011 at 4:29 am
positive pin of capacitor must be connected to positive supply…
i’m sorry i think you can’t replace the mosfet with original transistor.
No. 3 — January 25th, 2012 at 10:38 am
Hi dear how are you. This transistor are not availeable in our country. Please concern me for alternative transistor for replace here.
Thanks
jahir