As you can see, this PCB was dated Feb 22, 1974, which makes it fairly late in the 200-series line, before the switch to the 200A circuit.

Here’s the list of everything I did to it:

I opened it up and found that somebody had gutted the power supply / preamp and rigged up a 9V regulator.  It works, but there’s no tube reverb driver circuit anymore.  Not a huge deal, as this Compact is missing the spring reverb tank anyway.  They may have tried to run this thing on a 9V battery, as evidenced by the 9V battery harnesses.  I haven’t tried it, but I assume it would work for a few minutes until the battery died.

The guts of the Farfisa lift out after unscrewing three wing-nuts underneath.  This allows access to the PCB cards from the back.

Here’s the vibrato / pedal amplifier card pulled out.  It’s not a very elegant design, as everything is connected through about a mile of wiring internally, but it does make it relatively easy to service.

I also decided to recap all twelve oscillator cards.  These cards produce each of the twelve notes, and are labeled accordingly.  Tuning is adjusted by turning a threaded inductor core.  This is the “F” card.  There are six 1uF capacitors, a single 25uF, and a 50uF on most cards.  Some cards didn’t have the 50uF cap, and the “C” card has an extra 1uF capacitor, mounted axially.

There are twelve Germanium transistors on each card as well.  I see why people part these things out now, as you could probably sell each transistor for a couple bucks to people who build vintage-style guitar pedals.  That’s what gives these 60′s combo organs their unique sound.

Here’s the pile of caps I had removed after I was finished.

While I was in there, I also cleaned the key contacts with some spray contact cleaner.  I fired it up and it solved all the issues I was having.  It has a much better frequency response overall, especially in the bass notes, and it has a much more “cutting” tone when at maximum boost.  I tweaked the vibrato speed to have a greater difference between “slow” and “fast.”  It also needed to be tuned again, as almost every note was about a half-step flatter than before the recap job.  It was well-worth the effort, and really only took a few hours to do with the help of my trusty Hakko 808 desoldering gun.

Then I replaced all the capacitors and the NPN transistors, which should help eliminate some of the hiss from these things.  The EQ frequency points were also modified, as the stock values are somewhat useless.  I got to work on the chassis, measuring out the hole placement for all the controls.  After it was all mounted and wired, I checked it out and applied some finishing touches, like labels on the front and back and threadlocker on most of the internal screws.  The power supply board is one that I designed and etched.  I originally was going to use a Power One pre-built supply, but it was dumping a bunch of 60Hz hum into the audio through the EQ inductors, so I went with the LM317-based design and toroidal power transformer.

Another successful racking.  These get easier every time.

I guess the reason you would want this mod is to do momentary washes of noise.  The stock feedback knob controls how much of the signal is fed back into the delay memory.  Basically, it controls how many times you hear the delay repeat.  Turn it up too much, and you get a feedback loop that sounds like a bunch of awesome distorted noise.  There’s a sweet-spot in the rotation where it doesn’t quite turn into noise, but the repeats keep going for a really long time.  If you have a delay pedal, you probably know what I’m talking about.

Disclaimer:  Just for clarity sake, I’ll let you know that my Memory Man has had some mods done to it, including a true-bypass mod, upgraded opamps, input impedence mod, and probably some other stuff that I can’t remember.   Your reissue Memory Man may look different inside.  Also, I can’t guarantee that this mod is directly applicable to the newer Memory Man reissue, or to the (digital) Stereo Memory Man.  That being said, this is really easy to do, and it is probably doable for almost any analog delay pedal out there (with some minor tweaks, of course).

So, I ordered the cheapest volume pedal from ebay I could find.  Yeah, it’s a plastic volume pedal, but it’s not the worst that I’ve seen.  It’s made in Italy, not China, so that has to count for something.

I removed the four screws from the bottom and looked inside.

The potentiometer is a Piher 100k linear, which is a decent brand, better than you typically see in pedals.  For a volume pedal, a linear pot isn’t ideal, but that doesn’t matter in this case as we’re not using this as a volume pedal. In fact, it actually makes our job easier.  I’ll get back to that in a minute.

So, I desoldered all the stock wires and pulled out the two TS 1/4″ jacks.  We need to replace one of them with a TRS 1/4″ jack, like so:

I used a little threadlocker to keep it in place.

The pot is a 100k linear, but the one we’re trying to replace in the Memory Man is a 10k Logarithmic (audio) taper.  Fortunately, there’s an easy way to convert linear-taper pots into logarithmic taper: solder a resistor in parallel with the pot.  Granted, this only works if you need a pot that’s a lower value than what you have on hand, due to the parallel resistor formula.  In our case, a 12k resistor soldered in parallel with the 100k linear pot will turn it into a 10k log pot.  Read more about it here.  So, I dug out a 12k resistor from the handy resistor organizer I built a few weeks ago:

Total cost: about $15, including the resistors.  There are good deals on packs of 1% metal-films on ebay.  The container is from Harbor Freight.

Anyway, I soldered the resistor in place across the two outside lugs of the pot.

Then I added the wires.  In this case, I wanted to use shielded wires since the chassis of the pedal isn’t made of metal.  Less chance for noise.  Note the orientation of the wires.

Then I soldered the other end of the wires to the new TRS jack.  I picked white as the tip, because “red to ring” is sort-of standard convention.

We’re done here.  I put the bottom cover back on and tightened the four screws.  Then I started to tackle the Memory Man itself.  I never use the Direct Out on the Memory Man, so I though it was the perfect place to put the new TRS  jack.  I loosened the old TS jack first.

I pulled the back cover off, making sure not to rip off the ground wire that connects to the screw-tab on the back cover.  I always unsolder it when I’m working inside the Memory Man.  It just makes it easier to handle.

I then desoldered the wires from the Direct Out jack.  Your wires may be different colors than mine since almost all of mine have been replaced.

I dropped the new jack in its place.  The next step is to disconnect the existing feedback pot.  To get to it, all the knobs need to come off and the nuts removed from the pots.

This releases the circuit board and allows access to the feedback pot.  I desoldered two legs from the pot, leaving the ground leg connected.  I bent the unused legs away from the board.

Then I fed the pots back through the chassis and tightened them up, making sure not to pinch any loose internal wires between the pots and the chassis.  Using the wires I pulled from the volume pedal, I ran them from the feedback pot’s PCB pads to the new TRS jack, making sure to follow the convention I already started (white to tip, red to ring).

Technically, the black ground wire isn’t necessary as the chassis and the jack already make the ground contact.  However, a dedicated ground wire back to the pad is probably the best (lowest resistance) path.

After that, I replaced the back cover on the Memory Man, making sure to resolder the ground wire to it.  Then I made a short TRS to TRS cable and tried it out.

It works perfectly.  Yeah, I know my power LED doesn’t work.  Also, it probably doesn’t need to be said, but the feedback control on the MM itself doesn’t work anymore.  You’ll always need to have the expression pedal hooked up from now on.  Alternatively, a DPDT toggle switch could be installed and used to select between the internal and external feedback control, though it would require some minor drilling in the MM chassis.  That’s pretty simple to do though.

It’s really easy to get momentary washes of noise by flattening the pedal.  My original idea was to use a momentary footswitch to get the noise wash, but my friend Tate suggested the pedal for a little more versatility.  The momentary switch would be a slightly easier mod, from a wiring standpoint, but it would require drilling, either into the Memory Man chassis or into an external box.  So, there are multiple options here.

If you’d like this mod done, I can do it for $75 including shipping back to you.  While your Memory Man is here, I could do some other mods as well, such as the true-bypass and opamp mods I mentioned earlier.  If you have another type of delay pedal that you’d like a similar mod on, contact me and I’ll see what I can do.

First, here’s the schematic:

I didn’t change much.  The original was not true bypass, so I added a third footswitch for that.  I also put a jumper in place of R16 to give more output from the “Harmonic Mover.”

I used some old 4558 dual opamps I had pulled from an Orban 622B.  They have a date code from 1979. They’re in that transition period from metal-can to plastic casing.  I like them in guitar pedals, but that’s about it.

After I got the boards stuffed, I started drilling the enclosures and loading them up.  Tate picked a translucent copper enclosure, and I went for “cherry cola,” which is a metallic purple-brown.

The first section is called the “SDS,” which is a pretty cool sounding distortion circuit. It breaks up in what I can only describe as a “soft fart” sort of way.  It would be a good pedal to have on its own in a small enclosure.

Next is the true-bypass footswitch, and above that is the knob to select the three different types of Harmonic Mover modes, from most to least pronounced.

The third footswitch turns on the Harmonic Mover section, and the knob above that blends in the harmonics to the output signal.

Here’s a shot of the guts:

The finished products:

Tate’s has green/yellow bicolor LEDs for each section.  Mine has single-color purple LEDs.

Overall, it was a fun project. Definitely worth adding to my stable of pedals.

 The boards turned out great, but I need to get a new set of tiny drill bits, because I seemed to have lost mine during the move to Butte.  I’ll have another update in a few days when the rest of the parts show up.