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EP-2 for Korg

Posted: Mon Mar 09, 2009 1:02 pm
by KrzysiekK
Hello all, my first post here.

So, I am going to get the EP-2 pedal but not sure whether it will fit my Korg Triton Extreme when used as expression pedal. Anyone knows the pedal works (in full range) with Korg stuff?

Thanks,
Krzysiek

Posted: Mon Mar 09, 2009 10:12 pm
by Voltor07
Welcome to the forums! The EP-2 does not give the full spectrum on Moog gear, so I doubt it will give the full spectrum on Korg gear. But it might! Maybe you could do a search for EP-2 AND non-Moog gear under the search tab on the forums? The EP-2 has been mentioned many times before. :wink:

Posted: Tue Mar 10, 2009 3:02 am
by KrzysiekK
thanks for your fast reply. Yes, before posting I did a search but looks like nobody used it with Korg or Yamaha gear yet (apparently the pedals of these both are compatible). EP2 does not cover full spectrum on Moog gear? Weird :) Is there a simple way to apply mod to the gear (just in case)? I ask because I would have to go for it blindly.

Posted: Tue Mar 10, 2009 7:34 am
by EricK
Im sure that there are some specs out there for the actual Korg Foot pedals. Im also thinking that the EP2 is a CV pedal, and that the Korg Triton Extreme doesn't have any voltage controllable inputs.

Eric

Posted: Tue Mar 10, 2009 9:15 am
by GregAE
Okay. let's clear up a few things here. The EP-2 is an Expression Pedal, which means that it's basically a foot-controlled potentiometer on a TRS plug. Many instrument makers offer similar devices (Roland EP-5, Yamaha FC7, Korg EXP2, etc). The features vary somewhat from pedal to pedal, but all operate basically the same way, and any keyboard (or sound module) that offers a Volume or Expression Parameter input jack will accept these types of controllers. In my own experience, I've used a Roland EP-5, Yamaha FC7 and Ensoniq (remember them?) CVP-1 with my Voyager, Moogerfoogers and other instruments, and have never had a problem.

As for the lack of getting the 'full spectrum' from an EP-2, the answer is found in the Moogerfooger manuals. From the MuRF manual:

"When you plug an expression pedal into one of the pedal inputs on your MF-105, the pedal adds and subtracts half the range to the setting of the corresponding control... A good rule to follow is: when you use an expression pedal, you set the corresponding knob for the middle value you want. From the middle of the pedal, advancing to toe position increases that value, pulling back to heel position decreases the value."

It's also worth noting that the EP-2 has a control to adjust the range of the pedal effect. This is a handy feature for intentionally limiting the range of operation.

Finally, a last point that EricK alluded to: it is not a good idea to apply a Control Voltage to an Expression Pedal input unless the manufacturer states otherwise. I've contacted both Roland and Kurzweil about this previously, and both advise against applying a CV to the Expression Pedal input on their instruments (you risk damaging the instrument if you try it). As you might expect, they also recommended only using their brand of Expression Pedal with their products, but this appears to be a way to generate additional sales for the manufacturer, and not for reasons of compatibility.

Bottom line: If you're looking for a solid and well-built pedal (and a value, too), get an EP-2. You won't be disappointed.

Hope this helps.


- Greg

Posted: Wed Mar 11, 2009 2:31 am
by KrzysiekK
wow, great post Greg, thanks a million! Also thanks to EricK for setting up the problem

I was sceptical for the EP-2 for a moment but now I have to reconsider the idea. Probably a dump question - talking about CV you mean some another variable voltage (apart from the voltage provided by the keyboard itself for resistance measurement)? According to the doubts around possible damage using this voltage source, would you suggest replacing or adding some resistors instead (just in case)?

Also I am having some doubts regarding the range: assuming the pedal can cover just half range of given parameter (when used with Moog equipment), I thought the knob on EP-2 is used for shifting the range offset rather than expanding or shrinking it?

---

bottom line queston: I've read of the cheaper pedals introducing "stepness" to the resulting signal; is this a reliable opinion? How an analog device could introduce stepness?

Best regards,
Krzysiek

Posted: Wed Mar 11, 2009 8:29 am
by GregAE
KrzysiekK wrote: talking about CV you mean some another variable voltage (apart from the voltage provided by the keyboard itself for resistance measurement)? According to the doubts around possible damage using this voltage source, would you suggest replacing or adding some resistors instead (just in case)?
Correct - a Control Voltage is merely a voltage that controls a given device parameter. The CV could be a static voltage or a variable voltage like an LFO or Envelope. A static voltage might be used to set the pitch of a VCO, while a variable voltage (an LFO, for example) might be used to modulate the same VCO, providing vibrato.

Devices that are designed to produce and/or accept Control Voltages (Voyager, LP, Moogerfoogers, etc) do not require any external protection. Where Expression Pedal inputs are provided, you have the option of using either an EP or applying a CV to these jacks - no additional protection is necessary. This is not the case with Expression Pedal inputs that appear on other gear, like your Korg Triton. These EP inputs are not designed to accept anything other than an Expression Pedal, and should not be used with CVs.
KrzysiekK wrote:Also I am having some doubts regarding the range: assuming the pedal can cover just half range of given parameter (when used with Moog equipment), I thought the knob on EP-2 is used for shifting the range offset rather than expanding or shrinking it?
The EP-2 is a passive device, so the adjustment knob on the EP-2 can only limit the voltage range, it cannot expand it.

KrzysiekK wrote: I've read of the cheaper pedals introducing "stepness" to the resulting signal; is this a reliable opinion? How an analog device could introduce stepness?
An Expression Pedal cannot cause 'stairstepping' on its own. Any stepping would have to be the result of quantization of the pedal output by the receiving instrument, which would indicate a poor design or a faulty instrument -it has nothing to do with the pedal. An inexpensive pedal built with cheap parts and a plastic case is functionally no different from a well-built pedal that uses high-quality parts and a metal case. The well-built pedal, however, will probably provide years of reliable service while the cheap pedal might only last a few months, depending on the usage (if you play live, you'll want a pedal that's durable and road-worthy).

- Greg

Posted: Wed Mar 11, 2009 8:41 am
by KrzysiekK
thanks again for detailed answer. You confirmed all my suspictions

Best regards,
Krzysiek

Posted: Thu Mar 12, 2009 12:13 pm
by KrzysiekK
Hello again,

I have just luckily found the specs of Korg EXP-2 pedal (the one which I cannot get in my country, but fitting my model): http://lists.topica.com/lists/wavestati ... =904890237

Can I expect the EP-2 wil meet similar specs? Note that I want to use it as expression pedal, not volume pedal.

Thanks
Krzysiek

Posted: Thu Mar 12, 2009 3:21 pm
by Voltor07
EP-2=50K linear potentiometer. :wink:

Posted: Thu Mar 12, 2009 5:26 pm
by KrzysiekK
thanks Valtor.... so it won't fit the EXP-2 specs as expression controller since EXP-2 uses 100 k ohm log potentiometer? Ah, forgot about the fine attenuator in EP2 - in what range does this knob work?

Best regards,
Krzysiek

Posted: Thu Mar 12, 2009 5:47 pm
by Voltor07
KrzysiekK wrote:thanks Valtor.... so it won't fit the EXP-2 specs as expression controller since EXP-2 uses 100 k ohm log potentiometer? Ah, forgot about the fine attenuator in EP2 - in what range does this knob work?

Best regards,
Krzysiek
The attenuator is just to limit the settings of the main 50K pot. I'm not sure of its value. I believe it too is a linear potentiometer, though.

Posted: Sat Mar 14, 2009 1:29 pm
by KrzysiekK
Hello,
I would like to sum up this discussion by asking two questions:

- what is the resistance of main pot and attenuator knob in EP2 (so far I managed to find out the main pot is 50k)?
- in what range these two work (each of them)? 0 - 50k ?

Thanks,
Krzysiek

Posted: Tue Mar 24, 2009 11:12 am
by KrzysiekK
Hello,

I would like to say thanks to all of you who recommended me EP-2!

It works wonderful with my Korg Triton Extreme. Full 0-127 range with step of 1. The knob affects upper limit of range. When set in factory center position the range is 0-90, when I set it to around 3'oclock, the range is 0-127.

Best regards,
Krzysiek

Posted: Tue Mar 24, 2009 1:36 pm
by Voltor07
Cool! Glad it worked out for you! :mrgreen: