DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: soggybag on September 24, 2006, 12:48:20 PM

Title: AMZ FET Muff anyone built this?
Post by: soggybag on September 24, 2006, 12:48:20 PM
I found a drawing I made for a layout for the FET Muff the other and thought I might build this. I did a search on the forum and couldn't find any build reports? Has anyone built it?


-copyrighted schematic removed at the author's reqest-
The FET Muff is available on the AMZ-CD: http://www.muzique.com/amz-cd.htm


This shows 2n5457, would J201s work as a sub?
There is a 3uf NP cap between the diode detween G and Don the second and third Qs. This seems pretty large, is this essential or do you anything might work here?
Title: Re: AMZ FET Muff anyone built this?
Post by: markm on September 24, 2006, 12:55:32 PM
The J201's would give you alot more gain.
Title: Re: AMZ FET Muff anyone built this?
Post by: Gilles C on September 24, 2006, 01:13:03 PM
I tried different FETs in this circuit, and some sounded better than others. I had to use more than 10K with some FETs and I think (not sure I remember well, it was many years ago) the J201 was one on them.

The 2SK117 was good.

It is a fat sounding circuit with a lot of drive...

And I never used the diodes because I didn't have any NP at that time. Can't say about the caps.

Gilles
Title: Re: AMZ FET Muff anyone built this?
Post by: soggybag on September 24, 2006, 01:55:32 PM
I something I just notice about the FET Muff is that the G of the FETs doesn't seem to be biased at 1/2V+ as it is in most FET ciruits? Am I missign something or is this working on a different principal?
Title: Re: AMZ FET Muff anyone built this?
Post by: petemoore on September 24, 2006, 02:18:02 PM
G of the FETs doesn't seem to be biased at 1/2V+
  The gate should be close to ground, source above gate.
  It's the Jfet drain  that is commonly @ 1/2V bias.
Title: Re: AMZ FET Muff anyone built this?
Post by: Gilles C on September 24, 2006, 10:07:41 PM
http://ourworld.compuserve.com/homepages/G_knott/elect247.htm