Korg FK-1 VCF

The V.C.F. is still not fixed, but I felt I should add some more facts about it: this unit was part of the old Minikorg / Maxikorg line Korg had been building in the early to mid seventies. The filter construction was very much different from the later on MS series design, even though it already featured individual controls for the Lo- and Hi-Pass cutoff frequency. It indeed does have a Q- control: the "bright" knob; however it works for both filters at the same time and they can't be brought into oscillation.
If you carefully pull off the actual `traveler' knobs you may put `em back on with the molding bit poiting away from each other; now independent Hi-Pass action is possible without mutilating original vintage hardware. It looks a little odd nevertheless.
What else? Hm, I know a little more about electronics by now (just a bit more) and suspect the input buffer FET being faulty...
It should also be possible to build a little phone- plug to DIN adaptor with an attenuator into a little box and make it a CV'ed Filter as part of my MS- system.
A fabulous unit.

praise the fleamarkets of this world! this thing -to judge from its look- is pre-MS 20 era. and it laid right there among a lot of rubbish. this thingy consists of two parts: the actual box and a pedal with an on/off footswitch.
the box has a row of knobs that are labeled as follows:
expand: threshold - range; bright; balance;
in the second row there are two horizontal sliders -labeled `traveler'- connected in a funny way so that if you move the lower to the right, the upper is to follow, whereas the upper can be moved independently.
and to the left of that is a three-position-selector with the upper position reading `manual' and the lower `remote',however the middle position is not being labeled. to the right of the sliders there's a on/volume switch-knob. the in/ out sockets and the DIN socket for the pedal complete the whole arrangement. it runs on DC by the way.

but what the ... is it? well, a VCF of course. but probably one of the most versatile ones, least if you exclude modular units from the competition. those funny `travelers' are actually the cutoff -frq adjustments for a LoPass (top) and HiPass (bo:om). sadly the resonance is fixed `bout in the middle between self- oscillation and obscurity. i suppose this unit was designed for guitar players as a versatile wahwah -you get the picture. the cool thing is: you can use it as a non cv-controlled filter (which -i should mention- sounds absolutely fine) e.g. in combination with white noise or a drumloop; or you may use it as wahwah with user-definable characteristics; or-
you put the selector in the mysterious middle postion and take advantage of the built in envelope follower! one that gives you the choice to fine-trim your threshold and range -how d'ya like that? all in combination with that adjustable BandPass, mind you. i wonder whether it's been sloppy engineering or in fact a very thoughtful one that allows a small amount of cv from the pedal to alter the cutoff -frq when it runs in the env- follower mode. great!
the balance knob allows you to blend from the original signal to the filtered one. the bright knob had no detectable effect with my unit, but maybe there's something broken there.

so what could you do with it?
-use it as a WahWah for just anything: bass, guitar, HiHats, clavinet...
-use it as a filter for again just anything. if your bassdrum comes from a sampler you might want to just add some analog filter thud like with a SP-12 or a MPC-60.
-fuck around with the envelope- follower. i've sent a BOSS Dr.Rhythm 10 (the analog one) through it and made the whole thing sound a lot more abstract. but of course you can also use it with git's, basses, clavinets and what not.
and with all the knobs/ sliders under your fingertips... well, you know.

i'm afraid i have to admit something here: i've just got this thing last weekend (and played around with it a lot, as you might have guessed by now)so didn't have the time to have a tech looking at it. `cause actually there is something wrong with mine: the signal is extremly low and there's a loud hum. my guess is: it's the output amp. still i had a lot of fun with it! but well, this unit is well over 25... actually the box as well as the pedal are of sturdy metal, but the knobs look like they're likely to break if -say- a BOSS/IBANEZ/whatever stompbox fell on it.

well, i'm a little obsessed with auto-wahs. my favourite one for guitar and clavinet is the EHX Dr.Q. it sounds fabulous and stands far beyond competition, however it's not exactly versatile.
so in this field the winner'd be the EHX Q-Tron, just with that i always wished i could adjust the actual frequency- range a little more accurate than the high/low switch would allow. i also own a BOSS T-Wah and that DOD thing... they're both not shabby, but ...
so the KORG: again no one-size-fits-all, nevertheless there's a lot you can define yourself: frq-range independently for the HI- and the LO -pass, env -threshold and range. the missing knob for me would be the one for Q. plus it should be possible to move the `travellers' independently to allow for a HI-pass only use. the other thing being funny is the actual response of the pedal: its range is smaller than the envelope-follower's. that might be intentional, since a good WahWah is not so much defined by a large bandwidth, but by a pedal action that lets you work the interesting spectrum over a long way in the middle postion of the pedal. maybe that's something the could be modified with a switch...

as a conclusion i should again stress how much fun it was to play and twiddle around with it. and maybe from that point of few a missing Q pot isn't all that bad 'cause you stay focused on the actual cutoff action going on. after all, the fix Q sounds real fine and tasteful anyway. so that's the cool thing here: you can play around and have instant response while yer gettin groovey.