Cheap-and-dirty expression pedal build.

Discussion in 'Burnt Fingers DIY Effects' started by Rich_S, Feb 23, 2020.

  1. Rich_S

    Rich_S Friend of Leo's Silver Supporter

    Posts:
    4,596
    Joined:
    Dec 29, 2006
    Location:
    Potsdam, NY
    I wanted to add an expression pedal to my EHX Grand Canyon delay, so I can vary the wet/dry mix and regen on the fly, or do volume swells into long delays. So, I re-painted and re-purposed an old Cry Baby shell that I've had lying around for ages.

    [​IMG]

    Wile I was at it, I added a mini-toggle to switch modes. In VOLUME mode, it's just a simple passive volume pedal. In EXPRESSION mode, the input jack accepts a stereo TRS plug that mates up to the Grand Canyon's EXP input.

    [​IMG]

    Works great. Total cost: $0.00
     
    stevemc likes this.
  2. tah1962

    tah1962 Tele-Afflicted

    Age:
    57
    Posts:
    1,232
    Joined:
    Jan 27, 2020
    Location:
    Heart of Illinois
    Nice.
     
  3. kennl

    kennl Tele-Afflicted

    Posts:
    1,267
    Joined:
    Feb 6, 2007
    Location:
    Moon Township, PA
    Can you provide the wiring layout you used? SPST or DPDT switch?
    I built one for my Line 6 DL-4 and would like the volume pedal option.
     
  4. Rich_S

    Rich_S Friend of Leo's Silver Supporter

    Posts:
    4,596
    Joined:
    Dec 29, 2006
    Location:
    Potsdam, NY
    I used a DPDT. I’ll draw up a schematic tomorrow and post it.
     
  5. Rich_S

    Rich_S Friend of Leo's Silver Supporter

    Posts:
    4,596
    Joined:
    Dec 29, 2006
    Location:
    Potsdam, NY
    As promised.

    [​IMG]

    In Expression mode, the output jack does nothing and the input jack accepts a TRS stereo plug. The Grand Canyon sources 5 VDC on the ring and accepts a 0-5 VDC CV signal on the tip. I assume other CV-controlled pedals are the same.

    I used the Cry Baby's existing pot, which is around 125 Kohms. That's bit low for a volume pedal but it works okay, especially if you have buffers around it. I usually have a few Boss pedals in any effects setup, so I'm good there. Without buffers, the low pot value might cause some tone suck, but you can compensate with more gain and/or treble on the amp. Since the volume pedal doesn't have a bypass switch, the tone suck is "always on" and a tweak of the amp's controls should take care of it.
     
    Mouth likes this.
  6. Rich_S

    Rich_S Friend of Leo's Silver Supporter

    Posts:
    4,596
    Joined:
    Dec 29, 2006
    Location:
    Potsdam, NY
    Update: This week, I added a pot to adjust the heel position of the pedal. With a little tweak, I have it set so the volume starts to come up as soon as a start to move the pedal. Before, it had a little dead zone at the back. The 100K pot I happened to have is really too large, I'll swap if for a lower value once the world goes back to normal and Smallbear is open again.

    VX_2.jpg
     
IMPORTANT: Treat everyone here with respect, no matter how difficult!
No sex, drug, political, religion or hate discussion permitted here.


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.