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Jack Orman's Fet Muff

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1/4/1998 5:09 PM

Jack Orman's Fet Muff

For those of you who don't visit DMZ regularly, Jack Orman has just released the schematic and layout of a new distortion device, that he calls the Fet Muff. Go take a look.

Jack had mentioned this to me a ways back, and I'm glad he got it all put together and working. Jack's layout is available for making printed circuit boards, although there is no parts layout provided for it.

I had wanted to try this style circuit for a while, but I was too impatient to figure out the parts layout, so I just got out the layout program and did a layout of my own, same circuit, with parts diagram, etc. I'll post that on my web page if there's any interest.

1/5/1998 8:35 PM
Jack Orman	Because I got quite a few e-mail requests for it, I have added the parts layout to the pcb drawing for the FET MUFF. I also have recorded a .wav file to demo the sound but haven't got it uploaded and linked yet. Stay tuned. regards, Jack http://members.aol.com/jorman/

1/6/1998 7:32 AM
R.G.	Hey, great! Two ways to do it! My board layout and parts diagram are under the "New" link on my web page. I put it into a standard 2.9" by 1.5" board that fits nicely between the footswitch and controls in a Hammond 1590BB, so it works with the suggested diagram for putting effects in that box, also on my web page. I'm hoping to have one running no later than the weekend.

1/6/1998 1:47 PM

Great, I look forward to hearing your comments.

There are a multitude of modifications that can be made on the unit to change the sound, most all of which I'm sure you are familiar. The 0.68uF cap made a big difference in the heavy overdrive sound. Before I added that component, the sound was a trifle short on gain.

The tone becomes somewhat strident or brittle if you crank up on the drive too much, but in some cases that can be useful.

Check out the .wav file that I added to hear the F-Muff in action.

regards, Jack

1/6/1998 4:11 PM

While we're at it, did you try out using an interated fet stage (the schematic looks very much like this) and then attenuating between stages so that no stage is ever overdriven by more than about 3-6db? This seems to be the secret to getting no brittleness in the sound of a clipper.
That would at the same time eliminate the need for the 0.68 cap to get the gain up.

I guess I can just use the pcb layout macro capabilities to add on a couple of stages and try it out.

1/8/1998 10:32 AM
Jack Orman	Actually I think that the first stage gain overdriving stage 2 is contributing to the brittle effect. Removing the 10uF cap might help there, and leave in the 0.68 to give the high pass rolloff. Haven't tried this but it might be a better solution. regards, Jack

1/10/1998 5:02 AM

R.G.,
I have a trivial question, as usual, and a little off the subject... I've looked thru the info at your site dealing with effects DIY and I also saw your diagram for the 1590BB. My question is how do you attach the pc board to the enclosure? I noticed that your diagram does not show drill holes to bolt the board down. I also saw the pictures of the FD clone by John that looked like the board was attached by some sort of plastic stickem *thingys* (technical term). If anyone has any input, I'd really appreciate it, I'm pretty much a beginner and so far my projects have the boards just kinda danglin' in the box.

Thanks,
Jerry Sleep

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