Mfc 101 with ernie ball vp jr!?

BTW I remembered that Toneczar also offers a modified Ernie Ball Junior based expression pedal. So purchasing that is also an option. The mods look well built but I've not used one, they are not cheap and there is no need for the adjustable direction switches etc when just using with an MFC-101.

The Mission pedals are nice but I prefer the rear jack locations on the Ernie Ball Junior.

Darryl
 
Darryl Ramm said:
I too like the feel of the Ernie Ball Junior pedals. This is what I've used to mod several of them into Expression Pedals...

Honeywell/Clariostat 380C110K 10k ohm linear pot. High quality heavy duty construction.

Its a bit difficult to get a good quality ~10k ohm linear pot that will fit and will have the right rotation range etc. and will fit the string pulley used in the Ernie Ball Junior. And its clear from the Ernie Ball Junior pedals I've seen that the pulley does not fit the pot shafts properly on these pedals so even the manufacturer seems to be having problems sourcing potentiometers. But these Honeywell pots fit great.

Switchcraft 1/4" TRS Jack

This is typed from memory so here goes...

Disassemble the Ernie Ball Junior Pedal. Remove the three mono 1/4" jacks and circuit board from the back panel metalwork, discard jacks and circuit board. Save the existing wire between the pot and board to use between the new pot and TRS jack.

Unhook the kevlar drive string, remove the central black plate that the pot mounts on and remove the string pulley and pot.

Drill out the hole where the pot mounts to accommodate the larger shaft bushing on the Honeywell pot. You will also need to drill a new small hole for the anti-rotation/location tab on the pot body. Pay attention to where you drill this location hole so the pot body is rotated so the three solder tabs are pointing back most of the way to the rear of the pedal - so the solder tabs and wires won't foul on the pedal bottom or on the moving pedal top or the TRS jack. Install the pot on this plate and slide on the string pulley and mark the excess pot shaft length protruding past the pulley. Remove pulley, cut off the excess pot shaft with a fine hacksaw and clean up with a file. Reinstall the pulley. Some Loctite on the grub screw is a good idea. Trimming the pot shaft flush with the end of the pulley will make it easier to reinstall the drive string.

Install the 1/4" TRS jack in the rear panel left side hole as shown in the photos below (for most straightforward wiring) and solder wires from the pot to the three tabs on the TRS jack. The wiring is trivial, if in doubt follow the wiring in the photos below.

Reassemble the pedal following this guide on YouTube. If things are not going together don't panic -- just watch the video again, its easy to wind the string on the wrong way etc.

Attached are several quick photos of my modified Ernie Ball Junior....

When I get around to it I'll make a nice plastic label that covers the back panel and hides the two holes no longer used.

Darryl
Click to expand...

Hey Darryl, thanks for your detailed explanation and photos! I'm using 3 VPJr's into my MFC101: 1 for volume, 1 for wah, and 1 for delay attenuation. Obviously the wah and delay pedals would benefit from a linear pot mod...wondering if I should also mod the pedal I use for volume? or should I leave that pedal with the audio taper pot? Thanks for the link to the pot...kinda pricey but I'm guessing that's a really high quality pot? Plus as you mentioned it has the location tab...

I'd appreciate your insight...thanks!
 
I would swap all pots to be linear. It's better, and nice to have all pedals to be interchangeable. The log-response for the Volume effect is set inside the Axe-FX.

The pot I link to seem pretty good quality. When you are constrained by shaft diameter and sweep angle etc. there are not a huge number lot of choices out there.

Darryl
 
Darryl Ramm said:
I would swap all pots to be linear. It's better, and nice to have all pedals to be interchangeable. The log-response for the Volume effect is set inside the Axe-FX.

The pot I link to seem pretty good quality. When you are constrained by shaft diameter and sweep angle etc. there are not a huge number lot of choices out there.

Darryl
Click to expand...

Thanks Darryl! I'll get to work!
 
I've now modded all 3 of my pedals...a few tips:

1. These Honeywell pots vary a little bit in size and hang a bit below the mounting block which will kick the block a bit to one side. You could shim the block, but it will change the toe-down height slightly, so I opted for grinding a small depression in the aluminum chassis where the pot rests...works great.

2. The Honeywell shafts also vary...2 of the 3 I had to slightly drill out the brass pulleys to get them to slide easily onto the shaft.

3. Don't let the Ernie Ball video guy fool ya...restringing these is a PITA, but with a hook tool (made mine out of a coat hanger) it's manageable.

4. I cable-tied the wiring to keep it out of the way of the mechanism and I'm filling the empty holes with plastic hole plugs for a neat appearance.

Thanks again to Darryl for his tutorial!
 
You're a lucky man! :)

Either that, or you can live with all the action being bunched up at one end of the pedal's sweep.
 
oooo I just a regular Y cable at the local GC... it works great. No special cable needed.

2 Mono to 1 Stereo.
 
levipeto said:
oooo I just a regular Y cable at the local GC... it works great. No special cable needed.

2 Mono to 1 Stereo.
Click to expand...

And you won't have a linear sweep, which may or may not be a problem depending on what you are using the expression pedal for or your personal tastes. To try to tame the log sweep of the volume pedal pot presumably this Y cable has some extra fixed resistors. But its near pointless to complain about this cable not workign with any particular Volume pedal without telling us what resistance pedal you are using (e.g. EB Jr. 25kohm or 250 KOhm?). If somebody with one of these cables can measure the fixed internal resistance values and report that here it would tell us what this should work with/do.

Darryl
 
You must log in or register to reply here.
Back
Top Bottom