STFU, simply: DIY noise gate circuit

 

Here's another one that is, until I have time to build it on my own, UNVERIFIED.

I drew this from a schematic that someone named Matthes posted to FreeStompBoxes a couple of years back.

The more that I have gotten into using fuzz pedals with synthesizers and drum machines, the more I have grown to appreciate a good noise gate. Currently, I make the most out of the gate circuit in the Boss 1/2 rack RCL-10 compressor - but I'd like to be able to make one on my own that doesn't require obscure, out-of-production components or expensive THAT ICs.

This one that Matthes came up with seems to fit the bill. A single channel op amp (TL071) an NPN BJT (2n3904) and a P-Channel jfet (j175) are all pretty easy to come by. And yes, you are seeing that correctly - the 2n3904 has the collector, not the emitter, going to ground.

The drawing on the left is made for amplifier FX loop send and return jacks - so that you can place this gate between the preamp and power amp section of your guitar amplifier. This is the designer of the circuit's preferred method of use.

However, I included a modified version (the drawing on the right) for placing it in front of your amp's input. In this version, the sidechain out connects directly to the amp FX loop send (the source of the jfet) and the FX loop return becomes the output. Which is all according to the designer's notes in the FreeStompBoxes post thread.

I'm attaching the schematic from the original post, and will also attempt to link to the thread on FSB.