Modded Ernie Ball pedals with MFC101: help needed.

octatonic

octatonic

Experienced
I have a couple of Ernie Ball Volume pedals that I had a local tech replace the pot with a linear taper pot and put in a stereo jack socket (in the middle of the pedal panel).
It hasn't quite worked and I need some help.

The pedals still have the input, output and tuner sockets in there and the circuit board.

I am getting all of the expression data in the first 10% of the pedal movement.
I was hoping for it to be completely linear.
I thought that replacing the pot with a linear taper pot should have fixed this, right?

Should I have him completely disconnect the circuitboard/input/output/tuner sockets from the pot do you think or have I approached this in the wrong way?

Many thanks ppl.
 
octatonic said:
I have a couple of Ernie Ball Volume pedals that I had a local tech replace the pot with a linear taper pot and put in a stereo jack socket (in the middle of the pedal panel).
It hasn't quite worked and I need some help.

The pedals still have the input, output and tuner sockets in there and the circuit board.

I am getting all of the expression data in the first 10% of the pedal movement.
I was hoping for it to be completely linear.
I thought that replacing the pot with a linear taper pot should have fixed this, right?

Should I have him completely disconnect the circuitboard/input/output/tuner sockets from the pot do you think or have I approached this in the wrong way?

Many thanks ppl.
Click to expand...

Unfortunately this give us no real useful information about what was actually done to the circuit wiring. But I don't see any reason why you would want the original mono jacks left installed (its no longer useful as a volume pedal once the pot is replaced). I've previously posted a description on this forum about modifying the pedal, and anybody competent should be able to wire up an expression pedal for you--have them look at this thread . You should not be telling them what to do, if they are worth paying to do anything they should be able to easily do this.

Did you calibrate the pedal on your MFC? What value pot did the person install for you? The installer (or you) can check the resistance value with a multimeter as the pedal is swept and confirm the pedal/pot is working as expected. Has that been tested?

There are far too many threads covering expression pedals in general and in particular too many threads on Ernie Ball Jr. volume pedals as expression pedals. I've also posted links to commercially modified Ernie Ball pedals on some of those other threads. If your modified pedal does not work then you might want to ask for your money back and buy one of those pedals.

Darryl
 
Thanks for the info.
Yes, I calibrated the pedal in the mfc.
Ill check resistance today.

I'm not using the jnr- these are full sized EB volume pedals- (in case they are laid out differently).
I took it apart last night to have a look and it looks like he's just attached the exp pedal to the circuitboard in parallel with the other sockets which I guess is the problem, right?

I did do a search on this but actually but nothing came up with a circuit diagram- is it just a matter of attaching the stereo jack directly to the new pot?

The tech in question is usually great- eveything else he has done for me has been great.
This is probably my fault for not being clear about what I wanted.

Thanks again.
 
Last edited:
Ok, I removed the circuit board and have the pot connected directly to the TRS socket.
I am still getting the same response from it.

Called the tech- he didn't put in a 10k linear taper pot.
I asked only for a linear taper pot, not a 10k one (so my fault really... doh!) so he put in a 250k linear taper pot.

I guess this is the issue, right?
 
Last edited:
octatonic said:
Ok, I removed the circuit board and have the pot connected directly to the TRS socket.
I am still getting the same response from it.

Called the tech- he didn't put in a 10k linear taper pot.
I asked only for a linear taper pot, not a 10k one (so my fault really... doh!) so he put in a 250k linear taper pot.

I guess this is the issue, right?
Click to expand...

Yes, likely. Although you also need to ensure the pot is wired to the TRS jack correctly. See that other thread about the EB Jr. you should be able to work things out from there for your standard EB pedal.

Darryl
 
Thanks.

I am pretty sure it is wired correctly.

Red wire is tip.
Orange wire is ring.
Brown wire is ground.
 
Ok, so I just tried reversing the orange and red wires to see if it made any difference.
It did.

Now working properly.
So, just in case someone else is searching for this topic on the Ernie Ball (not jnr) volume pedals the wiring should be:

Orange to tip.
Red to ring.
Brown to sleeve.

Many thanks for your help Darryl.
I couldn't have done it without you.
 
You must log in or register to reply here.
Back
Top Bottom