KORG V-C-F FK-1 Traveler filter (aka Univox Korg Synthepedal)

[Pepe]

Your comment "lifted the resistor a bit, because the legs are insulated for the most part" is familiar. I've seen that before. Resistors from the ~1970s with painted legs looking like they have a good solder joint, but the paint is causing issues. I've had to scrape the paint off the resistor legs a couple of times in the past.

I *think* you might have a smoking gun here...

Yes, and that would explain why the fault came up when I applied heat to the diode. The resistor was right next to it. But it COULD have been the photo coupler as well. Thanks God, this is apparently not the case. I will power it for a few hours in a row to confirm that it is fully working again.

[Pepe]

I left the unit powered for over two hours and it is working without the slightest fault now. I'm so relieved! Thanks so much again for finding the culprit, Laurie!

Next step will be a modification of one of my three spare KORG FK-3 volume pedals to build the missing treadle control with the DIN 5-pin connector.

[laurie]

Glad it worked out!

[Pepe]

Next step will be a modification of one of my three spare KORG FK-3 volume pedals to build the missing treadle control with the DIN 5-pin connector.

Even better:

A few days ago an original FK-1 pedal popped up for sale at Reverb - and I bought it off from a cool guy in Italy who had this single control pedal for years, but not the effect unit. The pedal arrived a few minutes ago and it works great! Now I cannot only control the filter with my foot, I can finally also use the pedal's switch to engage the bypass sound.

I still have to treat it with my sprays and liquids of choice, because it crackles a bit and it is a little bit too stiff. But it is in almost perfect optical condition (pictures will follow!), plus it has the original "KORG V-C-F" label. KORG did also offer the FK-4, which was the very same pedal, but made for the legendary Polyphonic Ensemble synthesizers. And the Univox version had no label plate at all as it seems (I only found this picture of the Univox version which shows the front of the pedal).

korg_fk-4_univox_fk1.jpg (91.14 KiB) Viewed 1033 times

[laurie]

Nice score!

[Pepe]

I am very happy with the complete set. The KORG V-C-F has a very own and funky sound. And with the original foot control the performance is expanded enormously.

And now I also fully understand what the Manual ↔ Remote switch does. Another case of RTFM ("read the fine manual"), it might seem, but the original manual says the following:



That implies that the foot control doesn't change the sound in Manual mode and vice versa. But it does to some degree. The manual of the Univox-branded version is much clearer:



In any case this is an effects unit that you need to have in front of you to fully understand and hear what the controls are doing. It looks quite simple - a combination of lowpass and highpass filter. But with the manual control, the foot control plus the envelope control combined there is a lot going on and interacting with each other. It takes some time to tame this old beast, but then it will sound and perform like nothing else.

Here is a snapshot of the family reunion plus detail pics of the foot control.

[laurie]

I like the family reunion shot.