Korg Mr. Multi clone build.

[pinkjimiphoton]

the korg fk1 is an expression pedal for the korg guitar synth. it looks like the mr. multi, but it's just a volume pedal.

time to gut that sumbitch and build yourself an mk2!!!

[digi2t]

Anyone know if korg made any other pedal in the same treadle as the mr multi?

I just pick up a korg treadle pedal, on the basis of one photo, top down. It looks exactly like the mr multi, but I don't see the switches on the side - so I'm guessing its either a busted mr multi, or something else. Google didn't shed any light

For $20, I decided I'd take a gamble 

Thoughts, gentlemen?

And apologies for the necrobump, I figured this was the best place to ask.

J

No problem for the bump, good a place as any. I believe there were four FK models in that line. The FK-1 was the mono synth, the FK-2 was the Mr. Multi, FK-3 was a volume pedal, and the FK-4 was a control pedal for the FK-1 (had a sort of MIDI style jack on the side).

Like Jimi said, build yourself a Mr. Multi board, drill that sucker, and throw it in. $20 for the enclosure, great buy. If you`re not going to do anything with it, PM me.

Cheers,
Dino

[Govmnt_Lacky]

The Mr. Multi is FUNKY!! 

[the3secondrule]

Looks like the fk3 didn't have a stomp switch (although I wouldn't rule out it being added), so it's likely one of the others.
Should be here in the next day or so, I shall keep y'all updated.

I do have an fk2 clone in my pile of debugg, looks like the perfect excuse to get back to it...

[Ben79]

Just got one of these Mr. Multis in a semi-working state.

The double wah setting seems to be functional in both auto and pedal (though auto mode takes some time to start oscillating).

Wah does nothing in either mode

Phaser sometimes suddenly boosts my signal REALLY loud!  And doesn't do any phasing.

Inside it looks completely unmolested.

I've done some simple pedal repairs before but mostly only fuzzes.  Any ideas from these symptoms what might be ailing this old Japanese fella?

[digi2t]

Maybe test your rotary switches first, make sure that the contacts are clean.

As for the slow oscillation start time/wah not working, check the pedal pot.

If the pedal looks "unmolested", then I would start with the moving parts first.

[Ben79]

Thanks Digi2t, that's what I was thinking.  I'm just staying somewhere at the moment and don't have my tools with me so thought I'd see if anyone had come across the same problems before.

I'm thinking the pedal pot should be ok because it works fine in both modes for the double-wah (manually sweeps in pedal mode and controls the lfo frequency in auto mode)....am I missing something there?

[digi2t]

I'm sorry, I misunderstood,

Wah does nothing in either mode

, and took it to mean the pedal, and not the mode.

So, that brings us back to the switching. Schematic should be in my gallery, look in "Dino's stuff".

[pinkjimiphoton]

Formants... huh.

I checked all the wiring, and seems correct, except for the fact that I had to switch around the pot wires due to the pinion rack being on the opposite side. Like the original, the first position is phaser, then wah, and the third position is double wah (phase/wah).

Maybe yours has different caps? On the four "+" sides of the phaser opamps, the drawing I have has all 0.1uF caps. Can you check yours? Maybe it's got different value caps in there.

i can't believe this was 6 bloody years ago

i had sold mine at some point, but recently picked up another "broken". works fine.

so if there's any need i can always check parts, etc now... at least until i build one and sell mine again.

[Mark Hammer]

I have a Mr. Multi on the bench, currently.  I can't for the life of me figure out what the hell is going on with the "double wah" setting.  It sort of sounds like a Schaller "Yoy-yoy" though not exactly.

JC Maillet graciously drew and posted a schematic, but I honestly can't see much in there that is familiar, beyond 4 phase-shift stages.  What is going on there to produce the wah setting, and especially the double wah  What sort of filter is the double wah configured to be?  Is it a pair of counterswept filters?

[PMowdes]

The double wah should be a mixture of the phaser and the wah together

[pinkjimiphoton]

mark
i gotta working one here if ya need any parts verified or whatever, too.
deadendfx has boards, too.
the combo of phaser and wah is kinda cool, formanty. being able to choose between sweeping the wah and the phaser with the treadle, or let the lfo do it and controlling the speed with the treadle is fun

[Mark Hammer]

No need for parts, other than the gear I have to order from SBE, but thanks anyway Jimi.  I installed a 2.1mm power jack.  Everything on it works fine, although the speed pot seems to increase LFO rate at both ends of its rotation, which may be a byproduct of simply being old and worn out.  But I can definitely see why folks are fond of them, and why JC threw himself into reversing it with such abandon.  Some nice sounds, not to mention the perk of having foot control.