[218] Tillman Fet Preamp

Date: September 27th, 2008 | Comments : [1] | Categories: amps, DIY, power.

Tillman Fet Preamp

The Tillman jfet booster circuit is widely known in the DiY effects community and often recommended for certain guitar fx applications. I recently saw the circuit posted on a guitar forum and realized that it could be built on my Multi-Purpose pc board.

I’ve modified the instruction page for the pcb to show how to use it to build the Tillman. The instructions and parts list are on the site that is emailed to everyone that buys one of the boards. Ordering info:

AMZ MultiPurpose PC Board


One Response to “Tillman Fet Preamp”

[603] ken Smith Says: 11:00 pm, January 22nd, 2009

Hello. I am a total nOOb to effects and really do not have much interest in building, but I was referred here by some guys who suggested that I use a JFET circuit as a clean preamp for a 20Watt PP tube power amp that I want to use to amplify my POD guitar effects modeler. I need a preamp that will not clip easily, that adds no harmonic coloration in the preamp stage, and is hot enough to drive a Phase Inverter and push pull tube power stage. I have pretty good experience in amp building, having done 5 or 6 clones, but I have never designed a JFET circuit. Can you please refer me to a suitable circuit to use in this application? I do not mind buying an appropriate tranny to run the JFET at any required rail voltage. I need not be limited to a battery since it is going into an amp. I can just drop a V off the power supply at whatever voltage I need. I would gladly buy a board to build the circuit or a reference book if you might help me identify what might be a good candidate for my need.

I would like the JFET to handle a pretty hot humbucker without clipping, and of course to color the tone little if any. If at all possible, I would like to avoid having a separate gain or attenuation control for the JFET. I will have a Volume prior to the Power stage though, so, it might serve double purpose.

Can you suggest anything, or point me in the right direction?



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