Menatone JAC JFET Optical Compression

ahunter · Post by **ahunter** » 18 Mar 2019, 12:29

Wanted to buy one of these (menatone J.A.C.), but it seems it is discontinued. Wouldn't mind trying to build one myself. Anyone have any advice or diagrams and parts lists for creating a point to point optical compressor pedal?

karul · Post by **karul** » 18 Mar 2019, 14:03

Some guts. First one is from 2002. Others are from 2010.

ahunter · Post by **ahunter** » 18 Mar 2019, 15:24

Thanks Karul. Are the images from JAC's you own? If so, how do you like the sound? Is there a difference between the older ones and the newer ones regarding tone/noise/features? I think the footswitch component is different from the 2002 vs 2004 (from your images), and I have seen pics of later versions that have an additional knob, labeling changes, or can be smaller form factor and with a pad switch. I found a couple used ones on ebay so I may pull the trigger there, but would be fun to DIY (this would be my first pedal build; maybe i'm getting ahead of myself).

here is the inside of a 2002 model

karul · Post by **karul** » 18 Mar 2019, 19:15

No I didn't have the opportunity to try one my self. The pictures - I've pick them from the web. The first one is from talkbass.com the other two are from revreb.com

Shango · Post by **Shango** » 09 Nov 2019, 02:30

I got the chance to look at a 2002 version of one of these the other day, traced it to the best of my ability. Attaching the schematic I generated.

Couple things about the version I traced:
-The jfet transistors are TO-18 package, marked "M 0406", pinout appeared to be GSD. Can't find any info on them from a cursory google search, someone may know what they are/where to find them. Looks like the later version has trimmers feeding the drains of the jfets, so others may work? I am not an expert on compressor circuits.
-Opto looks like a homebrew LDR/LED, waterclear red.

Ian

Menatone JAC JFET Optical Compression [traced]