EHX - Stereo Memory Man Echo/Chorus - Reissue (analog)

culturejam · Post by **culturejam** » 02 Sep 2011, 00:48

Got this a while back in a trade. Don't own it now, but I thought I'd post the photos I took when troubleshooting. When I got it, there was a whistling that could not be dialed out. So I did some googling and bought the factory schematic and had a look-see. Turns out that a lot of these units had trouble with noise because of the clock chip (CD4047). I ended up replacing the 4047 and was able to get the noise about 95% gone.

This one has a single MN3005, a 571 compandor, CD4047 clock, and a slew of op amps. Seems to be a late 80s version, maybe. I'm not totally sure. Maybe theEHman can chime in.

The longer delay times, to me, sounded kinda crappy. Short times were quite nice, and chorus was monster lush.

So anyway, here are a couple photos of the PCB (one top and one bottom).

Lachlan C. · Post by **Lachlan C.** » 02 Sep 2011, 02:55

Hey CJ,
I have one of these for repairs/mods at the moment and can't find a schematic. Care to share your source for buying the reissue schematic?

Thanks - Lach

theehman · Post by **theehman** » 02 Sep 2011, 09:30

culturejam wrote:
This one has a single MN3005, a 571 compandor, CD4047 clock, and a slew of op amps. Seems to be a late 80s version, maybe. I'm not totally sure. Maybe theEHman can chime in.

That's a later reissue. The early reissues have a built-in AC cord.

culturejam · Post by **culturejam** » 02 Sep 2011, 13:02

Thanks for the clarification.

DJGlukBH · Post by **DJGlukBH** » 26 Aug 2013, 19:05

Hi, I'm sorry for some necroposting here.
Got the same unit with the damn noise. As per your pics I can see only two components replaced - the clock setting variable resistor and the CD4047 changed to HEF4047? So that elemininated the noise? With proper calibration, of course?