Expression pedal problem

[tomek27]

Hello everyone,
I am owner of Yamaha PSR-S 775 keyboard. I bought expression pedal: PROEL GF16L (https://www.proel.com/index.php?route=product/product&product_id=5379).
But in my opinion this pedal does not work properly. I can't precise regulate of volume, Articulation, pitchbend, etc.
for example: when I use "-" polarity and I lift up pedal the volume is 100% and in one moment is 0% but when I push pedal down the volume does not back to 100%. I must change the polarity to "+" and push pedal down when I want to back with volume from 0 to 100% at one moment.
Did anyone have a similar problem with expression pedal ?

Thank you,

[tyrosaurus]

Yamaha keyboards expect a range of 0 to 50 kilohm for a pedal to give a control range from 0 to 100% for the function that it is controlling.

The Yamaha FC7 has a 50 kilohm potentiometer and works fine with Yamaha keyboards.

The Proel GF16L has a 20 kilohm potentiometer so can never produce the full control range of 0 to 100% on a Yamaha.

It looks as if you have bought the wrong pedal!


Regards

Ian

[overover]

Hi Ian,

to MY knowledge, the exact value of the potentiometer (poti) inside an Expression Pedal is NOT that important. The poti works as an electrical "voltage divider" here. So the keyboard only evaluates the voltage RATIO, depending on the current position of the poti. You will always have the full control range (0 - 100%).

It should therefore work properly with resistance values ​​over a wide range (from appox. 10 kOhm up to 100 kOhm).

@tomek27
Please ONLY connect / disconnect Pedals when the keyboard is switched OFF.

During the boot process the keyboard will check the connected Pedals and it tries to automatically set the right Polarity. Important: Do NOT press / turn any of the Pedals until the Main Screen appears.

To change the Pedal settings press Direct Access button and then shortly press / turn the desired Pedal.

If the Pedal should work "reversed", change the Polarity. If your Expression Pedal does still not work properly, it is not compatible with Yamaha keyboards.

In this case, a technician can change the WIRING of the TRS plug. There are THREE different wirings possible, but only TWO of them can be used with Yamaha keyboards.

Best regards,
Chris

[mikf]

There are three settings to deal with. The Pedal itself has a polarity that can usually be changed. The keyboard can also change polarity. This essentially changes the direction of 0 to 100%. The third setting is span or range, which changes the amount of change you get from pedal movement.
You have to play with all three to get the pedal to work the way you want. And also you will want different settings for different functions eg pitch bend versus volume. Typically you want a volume pedal to go from 0 to 100% full up to full down. Whereas for example the span for pitch bend might be 2 tones with the full pitch being pedal full up. Within reason, the value of the potentiometer should not matter because you have these keyboard setting adjustments to compensate. But as the previous post stated, wiring does matter.
Mike

[tyrosaurus]

to MY knowledge, the exact value of the potentiometer (poti) inside an Expression Pedal is NOT that important. The poti works as an electrical "voltage divider" here. So the keyboard only evaluates the voltage RATIO, depending on the current position of the poti. You will always have the full control range (0 - 100%).

It should therefore work properly with resistance values ​​over a wide range (from appox. 10 kOhm up to 100 kOhm).

Hi Chris,

You are correct about this.

I have just jury rigged a 4.7 kOhm linear potentiometer (all I could find in my junk box!) to a TRS plug and it works fine on my Genos.   

Using this 'jury rigged' pot. the maximum keyboard volume at one end of its adjustment was just the same as when using my Yamaha FC7, and the volume reduced smoothly as I adjusted it giving the full range of volume control.

Thanks for nudging me into checking this properly!   

Apologies for any confusion caused to the OP, tomek27.


Regards

Ian

[tomek27]

Thank you for your replies.
The problem is not polarity, and as you said potentiometer.

Please ONLY connect / disconnect Pedals when the keyboard is switched OFF.
During the boot process the keyboard will check the connected Pedals and it tries to automatically set the right Polarity. Important: Do NOT press / turn any of the Pedals until the Main Screen appears.
To change the Pedal settings press Direct Access button and then shortly press / turn the desired Pedal.

I tried these steps with no results.

But in my opinon this could be the problem:

In this case, a technician can change the WIRING of the TRS plug. There are THREE different wirings possible, but only TWO of them can be used with Yamaha keyboards.

Does anybody knows TWO of them can be used in Yamaha keyboards ?

[andyg]

As I said in my reply on the other forum(!) not all pedals are created equal and some just don't work well, or at all on the Yamaha. Some work in a linear way, others do not. The FC7 is always going to be your best bet, and worth every penny.

Using a pedal for things like pitch bend etc, is not easy and it's a blunt tool as your leg and foot won't have sufficient control without considerable practice. For volume - its intended use on arranger keyboards - it's fine.

[mikf]

Andy
Have to say that I never found the expression pedal difficult to control, once I had it set up properly. It seemed much easier and more realistic than trying to use the wheel. I found I could even get a pretty decent guitar tremolo by moving the pedal up and down a small amount quite fast.
Maybe I had an advantage because I am a piano player, so using a pedal is second nature, and I also played some drums in my youth and foot /hand coordination is a basic requirement. I could never get any good though at bass pedals while playing the organ.
But I do notice that most guitar players use pedals all the time for things like wahwah or chorus and dont seem to have much problem adapting to this.
Mike