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markblack77

modding a cry baby to make an expression pedal.

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I had an old broken WAH kicking around so I thought I'd give it a go.

 

it works, not very well, but it works. I assume the pot value is wrong?

 

I was reading up on changing the value of the pot using resistors. would this work?

 

Would a 20k Bass WAH pot work better?

 

Am I flogging a dead horse? :)

 

Any advice / tips would be great.

 

got the idea fro here: http://www.strymon.net/strymon-tech-corner-2-build-your-own-expression-pedal/

 

IMG_20160719_205443.jpg

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Q: What are the specs for the Line 6 EX-1 Expression Pedal?
A: The Line6 expression pedal is a passive 10K ohm mono linear taper pot, using a standard 1/4 inch mono instrument cable.
http://line6.com/support/page/kb/_/general-faq/line-6-expression-pedal-ex-1-faq-r347

 

 

Q: What is different about the EP1-L6?
A: The Mission EP1-L6 Pedals are designed explicitly to support Line 6 devices. They are wired Tip and Sleeve as opposed to Tip, Ring and Sleeve in most other expression pedals. The Line 6 expression interface is different to most others in this regard. The EP1-L6 requires only a regular mono guitar cable in place of the stereo TRS cables required by other pedals. The EP1-L6 uses a 10k linear potentiometer for accurate tracking on the Line 6 processors. Since the EP1-L6 is wired TS, it is not polarity sensitive and so no polarity switch option is available.
http://missionengineering.com/?page_id=49

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The crybaby wah has a 100K pot in it? You could try putting a 10K resistor, or maybe a 20K pot, parallel to the existing pot, which should give around 9K, or 16.6K max if you use a 20K pot. Helix should be able to cope with that I would think. You should only use two terminals from the existing pot, the wiper (probably the middle terminal), and one other (not sure which one, measure with a meter while operating the pedal so that you get zero ohms in the heel position). The 10K resistor or 20K pot should go across these two terminals. Then solder two wires from the two terminals to the jack, tip and sleeve. Order shouldn't matter here as Helix now has a software polarity reversal. Use a mono cable.

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Thanks for all the replys so far - very good of you all.

 

That pot is what I'm after... just have to try and find one in the UK  :huh:

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Bummer.  Saw some on eBay too FYI.  Good luck on your pot hunt!

 

You're saving about $120 over the Mission EP1-L6 for almost exactly the same thing.  You don't get the cool Line 6 logo though ;)

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FYI to the forum, I sent an email to Mission Engineering to see if they would just sell us pre-wired/soldered pot/jack drop in expression pedal retrofit kits for our old Cry Baby pedals for about $40. I figure it's about $15-20 in parts and 1/2 hour labor with packing and shipping. Less if you can get bulk parts and an assembly line. They may even be able to get a similar profit margin with just the kit rather than the whole pedal. We'll see what they say.  

 

Maybe they could include a plastic plug for the hole when removing the on off switch and include a little grease pack for the gears.

 

Even $50 is better than $130, and you are reusing/recycling.

Heck, I would probably do it if you guys were interested. I know not everyone wants to deal with a soldering iron.

But really, Mission is a great US company with good expression pedal and FRFR offerings for us already. I would like to support them if they are willing.

 

Or Line 6 could do it and put them in their store ;)

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FYI to the forum, I sent an email to Mission Engineering to see if they would just sell us pre-wired/soldered pot/jack drop in expression pedal retrofit kits for our old Cry Baby pedals for about $40. I figure it's about $15-20 in parts and 1/2 hour labor with packing and shipping. Less if you can get bulk parts and an assembly line. They may even be able to get a similar profit margin with just the kit rather than the whole pedal. We'll see what they say.  

 

Maybe they could include a plastic plug for the hole when removing the on off switch and include a little grease pack for the gears.

 

Even $50 is better than $130, and you are reusing/recycling.

 

Heck, I would probably do it if you guys were interested. I know not everyone wants to deal with a soldering iron.

 

But really, Mission is a great US company with good expression pedal and FRFR offerings for us already. I would like to support them if they are willing.

 

Or Line 6 could do it and put them in their store ;)

 

To be honest I don't really need an expression pedal - I just like to tinker and I hate waste. Pot was shot in the WAH so just want to use it for something if I can.

 

I hear good things about the Mission pedals - I'd go that way if it was going to get enough use.

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I love this thread.  I recently was frustrated that you can't do a toe switch expression pedal setup with Helix so I gutted a old wha and then decided to go nuts with it.  Basically, I turned it into a actual midi expression pedal.  Give 9V and a midi connection to the Helix (or any midi capable device) and I now have expression with a toe switch.  Since I based the circuit around a RFDuino that meant I also had access to BLE so I went even crazier and built an iOS app so I can change the midi channels and the CC #s via my phone.  I have not added up parts cost or time, but it was a really fun project so worth it either way.  

 

I'm really impressed with the thought that went into the Helix overall, this was just a nit on my part.

 

 

post-2381324-0-20033000-1469137604_thumb.jpg

post-2381324-0-08480400-1469137630_thumb.jpg

post-2381324-0-37662600-1469137687_thumb.jpg

post-2381324-0-00494400-1469137712_thumb.jpg

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I love this thread.  I recently was frustrated that you can't do a toe switch expression pedal setup with Helix so I gutted a old wha and then decided to go nuts with it.  Basically, I turned it into a actual midi expression pedal.  Give 9V and a midi connection to the Helix (or any midi capable device) and I now have expression with a toe switch.  Since I based the circuit around a RFDuino that meant I also had access to BLE so I went even crazier and built an iOS app so I can change the midi channels and the CC #s via my phone.  I have not added up parts cost or time, but it was a really fun project so worth it either way.  

 

I'm really impressed with the thought that went into the Helix overall, this was just a nit on my part.

  

 

Yes!  Pedal hacks!

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Mission Engineering does actually sell some pedal upgrade kits.

 

This $39 kit is actually for a switching expression pedal , but looks like it has the parts for an EP1-L6 (10k pot, jacks, etc.), and maybe also the switch version SP1-L6H for Helix Rack.

 

http://missionengineering.com/?product=kit-a-2

 

It also looks like you can get a Mission / Line 6 logo pad and baseplate kit for $11.  They say it's for their older style Mission pedals, so I don't know for sure if it will fit a Cry Baby.

 

http://missionengineering.com/?product=upgrade-kits

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So the pot arrived and it works really well. Simple little mod that makes use of an old WAH - thanks for the help all.

 

Followed this from a2dconverterguy 

 

 

exp_pedal.jpg

 

 

IMG_20160726_210955+(1).jpg

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Perfect, I'll try the same!

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I have no problem admitting that I found a similar thread about modding a cry baby wah pedal to be an expression pedal and I failed so miserably that I ended up getting the mission engineering pedal. However because of this thread I have concluded that my own error was NOT changing the pot. It "worked" but it wasn't consistent at all. My own error. Thanks for this thread though, I have learned my own error and now have a solution. Hahaha

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I'm very intrigued by this, as I'm looking for couple of expression pedals for my Helix and I've got an old wah and an old defunct Roto Vibe that would be fun to toy with. Does the sweep of the modified wah provide a proper 0-100 in Helix? Is this something that can be adjusted in the settings? I just ordered a couple of these pots so I'll know soon enough, but interested to hear from folks who've done it. Thanks for the idea! 

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I'm very intrigued by this, as I'm looking for couple of expression pedals for my Helix and I've got an old wah and an old defunct Roto Vibe that would be fun to toy with. Does the sweep of the modified wah provide a proper 0-100 in Helix? Is this something that can be adjusted in the settings? I just ordered a couple of these pots so I'll know soon enough, but interested to hear from folks who've done it. Thanks for the idea! 

 

 

This is the same pot that is in my Mission EP-L6 expression pedal, and is 10kOhm with a linear sweep as in the Line 6 pedals.  No Helix adjustment should be needed to get the full 0-100 range.

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Thanks Roscoe! It's the physical travel of the foot treadle that has me wondering: if my donor wah (or the Roto Vibe chassis) has a different physical sweep distance between heel-down and toe-down than the Mission pedal does, that will affect how far the pot travels. Not sure if/how that is accounted for, or if it ends up being significant in the long run. I suppose that if the gears are the same, then the travel is probably reasonably similar from chassis to chassis.

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I'm very intrigued by this, as I'm looking for couple of expression pedals for my Helix and I've got an old wah and an old defunct Roto Vibe that would be fun to toy with. Does the sweep of the modified wah provide a proper 0-100 in Helix? Is this something that can be adjusted in the settings? I just ordered a couple of these pots so I'll know soon enough, but interested to hear from folks who've done it. Thanks for the idea! 

 

I have this working - needs to be the 10k pot to make life easy. Heal down 0% - toe 100% works perfectly. Being an old WAH is has a shorter sweep so it can be tricky doing very small increments with it. But then I use the main helix pedal is I need to do that.

 

Once I tweaked the pot to get the it in the right place it was all good - not adjustment on the Helix at all.

 

One thing to remember is the Helix uses a regular guitar lead - not a TRS jack like some others.

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I'm selling my Mission Expression pedal on Reverb if anyone is interested.

 

It works amazing and is in excellent condition (sill has the plastic on the bottom).  I just realized that I only used it on two songs so I can deal without it.

 

http://rvrb.io/ep1-l6-k3s

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Had total success modding both my BYOC wah and my Dunlop Roto-Vibe into expression pedals for my Helix. Many thanks to all who contributed to this thread!

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I'd like to also report that I had a total success with this mod as well.  I replaced the 100k pot with a 10k, de-soldered the input jack from the original PCB, then soldered the wires according to the diagram, and now this guy has a new expression pedal.  All this from a $15 part.

 

A huge thanks to everyone who contributed to this thread!

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Here's a pic from my mod of a spring-loaded Mission EP-1.  I thought it might be useful in case the pix above aren't sufficiently clear about which lug on the pot is hooked up to which part of the jack:

  • Red wire is Tip
  • Green Wire is Ring
  • Black wire is Sleeve

You could also put a jumper between the Green/Black lugs and only connect the sleeve if you have a TS jack.

 

 

4273d940cb840ce2cf30580897541854.JPG

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On 7/21/2016 at 2:56 PM, vickersr said:

I love this thread.  I recently was frustrated that you can't do a toe switch expression pedal setup with Helix so I gutted a old wha and then decided to go nuts with it.  Basically, I turned it into a actual midi expression pedal.  Give 9V and a midi connection to the Helix (or any midi capable device) and I now have expression with a toe switch.  Since I based the circuit around a RFDuino that meant I also had access to BLE so I went even crazier and built an iOS app so I can change the midi channels and the CC #s via my phone.  I have not added up parts cost or time, but it was a really fun project so worth it either way.  

 

I'm really impressed with the thought that went into the Helix overall, this was just a nit on my part.

 

 

post-2381324-0-20033000-1469137604_thumb.jpg

post-2381324-0-08480400-1469137630_thumb.jpg

post-2381324-0-37662600-1469137687_thumb.jpg

post-2381324-0-00494400-1469137712_thumb.jpg

 

I don’t mean to bring up old news but I love this and want to make it. I also made a midi foot controller on teensy that just has 5 switches right now but I have to go into the code all the time to change the cc value it’s spitting out. Do you know how i could learn to make a GUI like you?

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