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Equip a yamaha FC7 with second pot


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I have a pedalboard which is full. I have one FC7 mounted on it, but I have two boards. I would like to control both my Mopho (which is midied to an Audiothingies Micromonsta) and my Nord A1 with one yamaha FC7. After some reading I learned the best way is to have a second potentiometer with own cable mounted in. I know there are dedicated expression pedals with dual out, but I have a spare yamaha FC7 which I never use and like a challenge.

 

Anyone having experiences to share to do this? Which pot type should I buy?

Rudy

 

 

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Well that's a bit of coincidence because I have just ordered a stereo pot for my FC-7. The existing pot is not smooth anymore probably because the track is worn or dirty. I haven't been able to find a mono 50K audio or log pot to replace it. However, I have today ordered a dual gang or stereo pot from eBay. This is a 50K 16mm STEREO log Potentiometer, Flatted D-Shaft Dual Logarithmic Audio Pot. I think there is enough room to accommodate it and it would quite easy to route a second cable from it - you would need to drill a hole though. It should arrive by the end of the week. I'll let you know how I get on.

 

eBay

 

 

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The stereo pot fits easily - it's not much deeper than the mono pot. However, I ordered a log pot but when I opened the FC-7 and removed the pot it is a 50KB which is linear! I'm sure people have posted that it's a log pot. My FC-7 is about 6 years old and I'm sure I haven't changed the pot. Can anyone else confirm? I haven't been able to test it with my Nord yet but can't see it working.

 

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Can't confirm for sure, but can't imagine why it would be log and not linear. Log is used for audio taper, which is why it makes sense that a stereo pot would typically be log since audio is the typical use for those.

Dan

 

Acoustic/Electric stringed instruments ranging from 4 to 230 strings, hammered, picked, fingered, slapped, and plucked. Analog and Digital Electronic instruments, reeds, and throat/mouth.

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Hi Rudy- OB Dave attempted to modify the FC-7 with a dual pot as documented here

 

 

I believe the FC7 pot is indeed a 50k Log.

 

Many people talk about changing it out with a 10k Linear for better operation with certain boards.

 

Its all over the internet that this is a logarithmic pot. Not specified in the Yamaha FC-7 manual. If ChazKeys got to the pot :puff: and can see the number with a B designator I believe its linear. Of course someone could just test it if they were inclined.

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What about using MIDI to transmit from the keyboard it's plugged into, to the other keyboards? If filter settings are a problem or channel needs to be translated, a MIDI solutions box in between will do the trick.

Dan

 

Acoustic/Electric stringed instruments ranging from 4 to 230 strings, hammered, picked, fingered, slapped, and plucked. Analog and Digital Electronic instruments, reeds, and throat/mouth.

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Here's a photo. The other pot in the picture is the stereo one.

 

https://www.dropbox.com/s/156be2r8wdnlisb/IMG_1062.jpg?dl=0

 

I've owned 2 FC-7s and I'm sure I bought both of them new but I sold one so I can't check - but I don't remember noticing any difference between them in use. The one I kept worked well with my Nord E5D and a few other boards like the Legend. However, I don't have those boards any more. I had modified it to work with a Roland VR-09 by switching the tip and ring wires around and adding a 47K resistor. Wasn't too bad (probably because it's a linear pot) but the tracking was a bit jumpy at one end. As I was about to buy another E5D so I thought I'd replace the pot. Sadly the seller has changed his mind so I can't compare the log versus linear. Double whammy particularly as the E5D was great price! Ho hum - going to have to wait. BTW I picked up a Moog EP-3 after seeing the pedal spreadsheet that is posted on here (somewhere). Short throw but a nice solid pedal with a good range.

 

But back to OP question - isn't it possible to just make a Y cable - stereo socket to 2 stereo jacks - or would that cause some electrical weirdness between the keyboards?

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Interesting thread, I've been looking for a dual put expression pedal for a while that will work with my MODX and Kurzweil Forte so save space. Also looking for a switched (two seperate cables) sustain pedal. I've tried usual a dual 6.3mm adaptor but the MODX doesn;t like being coupled the the Kurweil Sustain, it must pick it up somehow and disable sustain.

 

Scott

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Its allover the internet that this is a logarithmic pot. Not specified in the Yamaha FC-7 manual.

 

As described in the linked write-up, the FC-7 uses a 50k linear pot, with a custom actuation range. So about half the range of the pot had no change in resistance, and the remaining range is linear, and linear range corresponds exactly to its motion created by the throw of the pedal. So you could say it's linear with a long flat portion. Definitely not logarithmic.

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As described in the linked write-up, the FC-7 uses a 50k linear pot, with a custom actuation range. So about half the range of the pot had no change in resistance, and the remaining range is linear, and linear range corresponds exactly to its motion created by the throw of the pedal. So you could say it's linear with a long flat portion. Definitely not logarithmic.

Thank you for solving one of life's mysteries. I often get an FC7 to use with my Roland A800 pro, so I carry the Ashby adapter (thank you Barryjam!). That gets me the full 0-127 range but I've always noticed (and been bugged by) the nonlinear way the controller values change. I much prefer getting a Roland or M-Audio EXP pedal.

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Interesting thread, I've been looking for a dual put expression pedal for a while that will work with my MODX and Kurzweil Forte so save space.
Can you plug the pedal into the Forte and use Kurzweil's MIDI-fu to forward expression messages to the MODX?

 

Also looking for a switched (two seperate cables) sustain pedal. I've tried usual a dual 6.3mm adaptor but the MODX doesn;t like being coupled the the Kurweil Sustain, it must pick it up somehow and disable sustain.
I've had variable results sharing a sustain pedal. Using an Oberheim controller under an Alesis QS - no problem. Oberheim under Nord - no dice. I've resorted to separate sustains, as I'm finding I might need independent control over the two boards.

 

There was a thing called a "Dual Sustain Single Pedal" (DSSP) but it doesn't seem to be available any more.

 

Cheers, Mike.

 

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using a switch sustain, add another switch.

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Interesting thread, I've been looking for a dual put expression pedal for a while that will work with my MODX and Kurzweil Forte so save space.
Can you plug the pedal into the Forte and use Kurzweil's MIDI-fu to forward expression messages to the MODX?

 

Also looking for a switched (two seperate cables) sustain pedal. I've tried usual a dual 6.3mm adaptor but the MODX doesn;t like being coupled the the Kurweil Sustain, it must pick it up somehow and disable sustain.
I've had variable results sharing a sustain pedal. Using an Oberheim controller under an Alesis QS - no problem. Oberheim under Nord - no dice. I've resorted to separate sustains, as I'm finding I might need independent control over the two boards.

 

There was a thing called a "Dual Sustain Single Pedal" (DSSP) but it doesn't seem to be available any more.

 

Cheers, Mike.

 

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Also looking for a switched (two seperate cables) sustain pedal. I've tried usual a dual 6.3mm adaptor but the MODX doesn;t like being coupled the the Kurweil Sustain, it must pick it up somehow and disable sustain. Scott

 

From the past, where different MIDI implementation in Obie, Yammy, Sequential and Roland made all kind of problems, I have some custom designed tools left over ...

There´s a box w/ a single sustain pedal (Yammi FCx) input and 4 separate outputs w/ individual polarity switches.

IIRC, there are relays inside for each output and it worked perfect.

The tech realizing these custom designs owned Oberheim, Sequential and MOOG authorized service at that time,- so it was pro work.

He also built me a low-noise CV controlled 19" rackmount stereo VCA I used to control overall volume of my entire rig w/ a single CV pedal.

It also allowed playing fade-ins and -outs in realtime w/ the entire (MIDIfied) rig,- zipper-noise free and regardless keyboards or rackmount modules prefered MIDI CC#07 or #11 or didn´t respond to such commands at all.

 

A.C.

 

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  • 2 years later...

Hello,

Sorry to resurrect this thread. I managed to inherit from a friend an old wah pedal carcass and decided to make my own expression pedal.

I have an EV5 as well so after opening it and looking at the wiring (10K B (linear) pot) I could reproduce it so now I have an extra expression pedal.

This works perfectly with a Nord NS2, but on a MODX8, the values jump all over the place, specially in the last part of the travel and it does not reach the maximum value. Completely unusable.

I could go and just buy a FC7, but I like diy challenges...

 

I understand that the FC7 has a special 50K linear pot, but the linear range is over ~90degress (the travel of pedal mechanism), so no standard pot swap would ever work... unless one modifies the carbon track. Since there are quite a few knowledgeable people here and thought I would seek some advice.

 

Given that the max resistance needed is 50k, but the range is only 90 degrees (out of ~300 degrees in most pots) (i.e. ~1/3 of the range) would the following work?:

Get a 50k*3 = 150K pot (if they exist), then use conductive (silver) to paint on the carbon track corresponding to the part that the pot never travels over (that is the last 2/3 of the carbon track). The remaining unpainted track should still have the 50K value and reproduce the voltage seen in the FC7.

Am I missing something obvious here?

Thank you.

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Well this is certainly next level! Wouldn't you have to disassemble the pot to do this? Sounds a little scary! :)

 

I take it you saw the thread I started about that FC7 pot? There's a post in there by one of our resident electronics experts here, MIDI2XS, with the exact Yamaha part number: WF876300 VR ROTARY B 50.0K RK1631110G. It might save you a lot of time and trouble to just order that pot. However, just to confuse things more: I connected my M-Audio EXP expression pedal to my Yamaha KX88. It has a switch to reverse the tip & ring so it's Yam-compatible, however I'm pretty sure it does not use any kind of special pot. I put a scope on the midi output of the KX and it was perfectly smooth from 0 to 127 â worked perfectly.

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Thank you Reezekeys for the reply and the part number!

Yes a bit scary, Ha ha! but perhaps not impossible.

To complicate things a bit more, I realised that the pedal I am trying to refurbish has more than 90 degrees movement (about 120), so I fear the original Yamaha would not work perfectly either. I need to recalculate the values above more precisely.

If nothing works I might end up getting a FC7 anyway (which should work in the Nord, via a system setting) but it is tempting to try the idea above and perhaps add a 2nd gang pot so it is a double expression pedal.

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