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Digitech PDS1002 glitch mod

Started by marmora, March 26, 2016, 03:19:30 PM

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marmora

Hi friends,

Here's a mod that is originally from Nevin of Fruitsnake Bends:
http://reade2016.wix.com/fruitsnakebends

He gave me permission to post this along with my findings.

Here's what he had to say:
"The modification itself is actually very simple; an SPST switch is soldered between two points on one of the ICs, creating a controllable short-circuit. If you open up the 1002 and hold it with the output to your left, looking at it from the bottom, the IC that you want to address is the third from the left in the top row. Look at the leftmost row of pins on that IC, and count the pins starting from the bottom and moving to the top (the pin closest to the pedal casing should be number 8 ). Solder pin 2 and pin 7 to the switch, and you're done!"

As I experimented with this bend, I found that connecting pins 4 and 7 (going by Nevin's numbers) also created a similar but distinctly different sound.
I used a SPDT on/off/on toggle with the middle lug of the switch connected to pin 7 and one outer lug to pin 2 and the other lug to pin 4. This way you have your regular sound and two lofi bit-crushed rhythmic pitch-shifting modes.

I'm adding a video, but as you can probably tell, there are way more sounds to be found. Especially when the Repeat Hold button is on and you start turning the time knob. An easy way to lose a couple hours.


madbean

Dude...cool! I will definitely give this a try. I have two...one stock and one I modified to use an expression pedal for the delay time. I think I'll put it on the second one. Was also thinking of putting in a filter control for some tone variations. I love the old PDS1002.

marmora

Quote from: madbean on March 26, 2016, 03:24:01 PM
Dude...cool! I will definitely give this a try. I have two...one stock and one I modified to use an expression pedal for the delay time. I think I'll put it on the second one. Was also thinking of putting in a filter control for some tone variations. I love the old PDS1002.

Hey, thanks! Yes, the PDS series is still a lot of fun.
One word of warning: I did notice some faint high frequency whining in the background after I did the mod which seemed dependent on what power supply I was using. It could have been there before the mod as I only had the pedal a few weeks before I took it apart. This is audible when the mod is off and even when the pedal is bypassed.
Your mods sound cool too. I've considered the expression pedal mod, a slam switch and more, but at some point I have to just put down the iron and play a little haha

madbean

Here's what I am thinking for the tone control - you could put a cap and variable resistor to ground in parallel with C29 or C25 (after the expander). Maybe 10n and 10k. Or, perhaps something off pin7 of U1B. Those all seem to be likely candidates.


marmora

Hmm, maybe I will have to open up my PDS again after all.

I think FX Doctor was doing a high cut control on these, but haven't seen/heard anything else about it.

Doorlord

never could stand the switches on these. Here's my old PDS1000, I just hacked these switches in today. Had to file them down a bit where they hit the board.