My Korg FK 1 VCF pedal.

[DrNomis_44]

Hey Everyone,


Thought I would start a thread about another one of my little guitar toys, this time it is my Korg FK 1 VCF pedal, I bet some of you haven't seen one of these things before, they are considered to be a pretty rare 70's vintage effects device, anyway, here's a pic of it:




A good mate of mine gave it to me.....for nothing.


Update:

I guess you guys are interested in hearing what this thing actually sounds like?, want me to do a demo of it?


For those of you wondering what VCF stands for, it stands for Voltage Controlled Filter, a VCF is basically a filter that has a voltage-controllable cutoff-point, the cutoff-point of a filter is the point at which a signal's loudness falls to about -3Db (sorry for the technical terms), so the higher the control-voltage you feed into it, the higher the filter's cutoff-point will be, a filter is an electronic circuit that lets some signal-frequencies through and stops others, the tone controls found on electric guitars is an example of a filter, voltage-controlled filters were one of the essential modules found in Analogue Modular Synthesizers, like the Moog Modular Synthesizer, the Voltage Controlled Filter was used most often to shape the timbre, or tonal-colour of a sound generated electronically by a Synthesizer, if you feed a signal from a guitar into the Korg FK1 VCF you can change the tonal-colour of the guitar from bright to dull, or anywhere in between, it can be used as an auto-wah pedal, it will react to how hard or softly you pluck the strings, or, you can use the footswitch to control it, or you can even control it both manually and automatically at the same time, if you feed the output of the Korg FK 1 VCF through a chorus, delay, and reverb pedal you can get some very spaced-out sounds.

[Fretworn]

Doc, yes demo it. That would be worth a bit now days if it in good working order. (Actually I found one online for USD 1,000.)

[DrNomis_44]

Doc, yes demo it. That would be worth a bit now days if it in good working order. (Actually I found one online for USD 1,000.)

I'll see if I can work up a quick demo of it then, first by itself and then with some added fx pedals, I tried it out a few days ago and it does seem to work, had to replace the internal mains fuse first though, but it does appear to work.

[Simon Barden]

I've got a Moog Mooferfooger filter pedal that does a similar thing (though something's wrong with it as it's very noisy indeed). It's akin to an auto-wah, but a bit more subtle as it doesn't boost a centre frequency, just filters off the higher frequencies above the filter point. It's almost a glorified passive guitar tone control as you can create a similar effect by rapidly moving the tone control knob (though this makes playing the guitar very difficult to do at the same time). I don't know if the Korg has a resonance control, but on the Moog, turning that up high can get the filter to self-oscillate. Just below that, the sound becomes a lot more peaky, and more like a wah sound.

[DrNomis_44]

I've got a Moog Mooferfooger filter pedal that does a similar thing (though something's wrong with it as it's very noisy indeed). It's akin to an auto-wah, but a bit more subtle as it doesn't boost a centre frequency, just filters off the higher frequencies above the filter point. It's almost a glorified passive guitar tone control as you can create a similar effect by rapidly moving the tone control knob (though this makes playing the guitar very difficult to do at the same time). I don't know if the Korg has a resonance control, but on the Moog, turning that up high can get the filter to self-oscillate. Just below that, the sound becomes a lot more peaky, and more like a wah sound.

Yep, the Korg does have a resonance control on it, it's actually the control labeled "Bright", I've tried turning it up to maximum but the filter doesn't go into self-oscillation like the Moogerfooger does, although it does get a bit peaky, apparently the voltage-controlled filter in it is the same one used in the Korg MS series Synthesizers.

You could try spraying the pots and switches in your Moogerfooger with some electrical contact cleaner and see if that gets rid of some of the noise, what kind of noise is it?, is it hum or crackling and hissing?

I did do one demo recording of the Korg FK-1 but it was really just free form sounds, I'll do a more conventional demo of it in the morning, will post a link once it's done.

[Simon Barden]

It's hiss. It's a lot louder when the 4-pole filter is selected compared to the 2-pole. It's independent of any input signal. Had a look inside but there's nothing obvious. Only a few small electrolytic caps on an otherwise SM board and they look fine. It's almost as loud as the guitar signal in 4-pole mode, not at all background. I need to try it into a line input again instead of my guitar amp, as I don't recall it being noisy when I was feeding my Korg Odyssey synth through it.

[DrNomis_44]

It's hiss. It's a lot louder when the 4-pole filter is selected compared to the 2-pole. It's independent of any input signal. Had a look inside but there's nothing obvious. Only a few small electrolytic caps on an otherwise SM board and they look fine. It's almost as loud as the guitar signal in 4-pole mode, not at all background. I need to try it into a line input again instead of my guitar amp, as I don't recall it being noisy when I was feeding my Korg Odyssey synth through it.

You could try swapping out the resistors for metal film types if the originals are mostly carbon film types, doing that might reduce the hiss noise a bit, you might need to trace through the signal path with either an audio probe or a scope to find out where the hiss noise is coming from, I'm going to record a demo of my Korg FK 1 shortly, just having my daily coffee fix at the moment.


Update:


Here we go, here's a quick demo recording of my Korg FK-1 VCF pedal, this is really just to give you an idea what it sounds like:

https://dl.dropboxusercontent.com/u/...VCF%20Demo.mp3

[Simon Barden]

It's an interesting sound that's good for adding texture to a track, but it's a sound that's easy to overdo.

[DrNomis_44]

It's an interesting sound that's good for adding texture to a track, but it's a sound that's easy to overdo.

Yep, but on the other hand if you want something that's 70's Funk sounding then I reckon the Korg FK-1 is probably in the ballpark, it seems to work pretty well with my Boss RE20 Space Echo pedal.


I reckon it'd be great on a Dub Reggae track.

[Andy40]

Thats a cool pedal Doc...cant believe you got it for nothing