Korg Forums

[Ceyhan]

Hello fellow Korgers,

I got a new Boss EV-30 dual exp pedal for the original KingKorg. In the calibration it goes from the half to the high. I want it to go all the way from 0 to 120 cutoff. It says calibration error. I tried many times and just once the calibration was successful.

When the foot pedal is set to JS-Y, in some programs the pedal works as cutoff (if joystick is set to cutoff) however I want to use this pedal for cutoff all the time regardless of the program settings.

I selected cutoff at G28 page in the global menu. Function is set to Pedal, and foot pedal is selected. These are my current settings at the global.

Can you help me to control cutoff with this pedal like 0-120, so when I leave the pedal on mid position it will use the original cutoff setting of the program?
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg

[voip]

Is the "Min" knob on the pedal set to give the lowest possible "pedal up" minimum value, and is the polarity set to "Nor"?

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[Ceyhan]

Hello dear voip, I tried different positions with MIN knob, when it is set to minimum level, the range of the pedal goes like 30%. When the knob is set to 50%, the pedal range goes to 50%. Nothing happens after knob 50 to 100. It stays the same 50%. However I need a full range of 100, that way I can go -value / original / +value. And I get a calibration error %99 of the time.

I tried both polarities, no change observed, my last setting was NOR.
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg

[voip]

Hmm. Something doesn't quite seem right.

Is the EV-30 pedal being used with a stereo, or TRS cable?

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[Ceyhan]

[voip]

The KingKORG user manual recommends the Korg EXP-2 or XPV-10 pedals for the pedal functions, such as expression. The XPV-10 has now been replaced with the XPV-20 pedal, but is essentially the same, electrically.

Having seen various discussions on the web about this, the connections for the Korg pedals have been described as RTS (meaning the Ring terminal on the jack is connected to the potentiometer wiper inside the pedal), whereas the BOSS EV-30 is a TRS pedal (where it is the Tip terminal that is connected to the potentiometer wiper inside. This makes all the difference to how the pedal operates with the KingKORG.

In the KingKORG itself, because the Pedal input has been designed to accommodate both switch and expression pedal types, the Ring and Sleeve terminals are both connected to Ground, and the Tip terminal is pulled high inside the KingKORG by a 10k resistor. This means that, with the Boss EV-30 pedal, the expression signal first increases and then decreases as the pedal is moved across its range of movement, so not ideal, as your observations have shown.

There are two possible solutions:
1) Buy an EXP-2 or XVP-20 Korg pedal.
2) Buy a 1/4" stereo to two 1/4" mono L & R splitter cable. Connect the stereo end to the pedal itself, and one of the mono jacks (I think it will be the "Left" channel one) into the KingKORG. Something like:

https://www.amazon.co.uk/Copper-6-35mm-Stereo-Splitter-Breakout/dp/B08TTJYX9T

Option 2 is the cheapest. You may already have the necessary cable lying around. An even cheaper option would be to cut the wire going to the Ring terminal at one end of the existing TRS cable, or make your own custom TRS cable that only has the T and S connections made. Another thing to try would be to make a TRS cable, where the T and R connections are swapped at one end, and see what works best in your particular setup (this last suggestion will give a different result to changing th setting of the Polarity switch on the EV-30.

There is a further consideration to this. The Boss EV-30 pedal has a 10k potentiometer inside, whereas the corresponding value for the EXP-2 is 100k, and XVP-10/20 are both 50k. This will affect the linearity of the pedal position to expression signal relationship on the KingKORG. The Korg pedals will tend to give a greater rate of change in expression signal at the end of their pedal travel, than the Boss pedal. It may be possible, even likely, that the Korg designers will have compensated for this in the way the expression signal is handled and evaluated inside the KingKORG.

Don't forget to perform the pedal calibration on the KingKORG, after making any changes to the pedal arrangement.

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[Ceyhan]

Hello dear voip, I read your post word by word and understood 90% of it So now I ordered a Korg EXP2, I'll share the results. I wonder if XVP is better or what is the difference for the double price? Thanks a ton!
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg

[voip]

The XVP-20 pedal construction is a lot more solid than the EXP-2, plus it has two volume channels, compared to the EXP-2, which has a single [mono] volume capability. I've just measured the expression potentiometer resistance on my XVP-20 pedal, and it is 100kOhms, not the 50kOhms I previously mentioned. It is the two volume potentiometers on the XVP-20 that are 50kOhms. (I called it the XPV-20 in my last posting, sorry for any confusion).

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[Ceyhan]

Hello, Korg EXP2 instantly works, in calibration it covers the 9/10 of the range (maximum) and it is set to cutoff. However when you start to use it, it only uses 30% of the pedal range. When you press to the pedal, the sound is completely gone after 3/10 range, the rest does nothing. It would be nice to use all the range for a more sensitive control. This is just too fast. I set it to the minimum, tried both outputs.
Now I am thinking to buy an XVP-20 to try that one. I hope it covers 10/10 in the calibration and uses all the pedal range for smooth and slow filtering.
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg

[voip]

What happens if the EXP-2 pedal input is set to generate Expression (CC#11) messages? Does the volume of the played sounds increase steadily, as the pedal is depressed, or does the change all happen at one end of the pedal travel?

When calibrating the EXP-2 pedal, have you tried starting the pedal movement straight after pressing the button to start the calibration, and moving the pedal slowly, starting from the heel down and moving to the toe down position (say over 3 or 4 seconds), and then pressing the Value dial straight after, to save the calibration?

The KingKORG's method of deriving the pedal position signal from the pedal's variable resistance (i.e. potentiometer), is intrinically non-linear in response to pedal travel, and the amount of non-linearity has to be determined somehow. Making a steady movement of the pedal during calibration, might be one way that the KingKORG does this. I don't know how the calibration is done inside the KinKORG, but if the calibration process described in the above paragraph works, then that's good to know.

I think that the results obtained with the XVP-20 pedal will be very similar to those seen with the EXP-2.

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[Ceyhan]

Yes the results are same as EXP-2 and XVP-20, it is just cooler and more sturdy physicalwise. The first half of the pedal range goes so slow almost no effect and the rest goes very fast, making 70% of the pedal range useless. Cutoff filtering starts and ends in the 30% of the pedal range.

I tried slow calibration, no luck there.Expression mode does the same with Kingkorg, the change happens at the end of the pedal, making it fast therefore far from smoothness.

Thanks for your contributions to this community. I hope I am doing something wrong. I will take a video and upload to youtube where you can see the thing that I am not doing right. Thanks <3
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg

[voip]

So, from the results you report, it seems that Korg didn't work out how to linearise the pedal input signal properly, even though the EXP-2 and XVP-20 pedals are recommended by Korg. That's a bit disappointing!

There is, I believe, a solution, in the shape of the MIDI Solutions Pedal Controller:

https://www.midisolutions.com/prodped.htm

Out of the box, it is set to produce volume control change messages (CC#07) in response to pedal movement, but it can be set up to give any CC# message that the user wants, using the MIDI Solutions Programming Tool, so CC#01 for joystick +Y, for example. Programming is done using a computer and MIDI interface. The KingKORG's own MIDI Out port could be used for this purpose. Once programmed (the Pedal Controller retains the programmed settings), the Pedal Controller is connected to the MIDI In port and takes its power from the MIDI port itself, so there's no need for an extra power supply. The software can be downloaded from:

https://www.midisolutions.com/progtool.htm

The software is free, and compatible with all of their products, so it's possible so get some sort of preview of what the devices can do. According to the MIDI Solutions product page, the Pedal Controller gives a linear response to pedal movement. What might be of particular interest to you is that it can also introduce various amounts of curvature into the pedal movement vs response, and the curve direction can either be upwards or downwards.

Another solution would be to use a pedal buffer amplifier, but I cannot find anything on the market that would be suitable for working with an expression pedal and the KingKORG.
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[Ceyhan]

[Ceyhan]

Unlucky, my software was already the latest one, 1.13
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg

[Ceyhan]

Hello dear Kingkorgers, the most compatible foot pedal is Behringer FCV100.
Plus you won't need to power it if you use it as filter changer(foot pedal).
I bought 4 pedals for this, I hope this experience helps you guys.
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Karma, Triton, Kronos II, Krome, SV-1, Micro-X, X-50, X5D, Kross 2, Grandstage, Opsix, Microkorg S, R3, KingKorg