Acrobat Parametric Distortion

comradehoser

Well-known member
I think this might be my first "proper" build report--not a PTP.

It's not particularly exciting--There really isn't a lot of extraneous skilled stuff to show off with like tidy off-board wiring--this thing was titetitetite. I have to say, I don't think I like board-mounted jacks much, but that might be a function of the fact that I hand-drill all my enclosures. The nice white enclosure was because stompbox parts didn't have any bare aluminium ones in stock. I did put some nice knobs I sourced at Lee's Electronics last time I was home on there so it would look good, but as is usually the case, I neglected to put on a real graphic or LEDs in favor of building another pedal. Still my most pro-look Gucci pedal so far.

The one thing I did do was add a volume pot. Why, you may ask?

Well.

6 controls: left 3pdt toggles between clean (top center gain knob does nothing) or dirty. Right 3pdt is bypass. Center bottom knob is a selector switch that controls the width of the frequency spectrum affected by the pedal--can go from quite wide to quite narrow. The narrower the selection, the more noticeable the effect. Center top knob controls gain and amount of clipping in "dirty" mode. Left center knob sweeps the frequency spectrum up or down. Right center knob controls the amplitude of cut (CCW) or boost (CW) with center being flat.

Basically, you can dial a whole bunch of sounds with this. Selection switch somewhere in the middle, amplitude knob at 2:00 boost and sweep knob at noon-2:00 can give you a tube-screameresque mid hump; move the amplitude to 9:00 to cut, and dime the gain, and you can have a pretty good big muff mid-scoop imitation. If you sweep the cut down into the bass frequencies (around 9:00), you can get chonky tite chugs. The distortion is pretty alright--it has it's own character, but I don't think it's going to boot off the low gain or high gain specialist distortion pedals (Tyrian, for example).

BUT, the one thing that was very difficult to deal with for me is that the volume is really all over the place (in my build, at least), from unity to WAY above unity in the dirty mode, depending on setting (especially when amplitude approaches 12:00), so I inserted a volume pot the only place I could see would clearly work. Not ideal placement, and I initially cut the wrong wire to the jack out making the pedal a volume control in or out of bypass. Fixed at the cost of an ugly solder. Maybe I should have gone for between the 3PDTs (and I still might).

So, @Robert howzabout that special expression pedal adapter-type deal, eh?

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whats going on with the side knob there? Also where did you get those knobs on the left and right? Killer knob selection.
 
whats going on with the side knob there? Also where did you get those knobs on the left and right? Killer knob selection.
This pedal is loud as hell, I'm assuming it's a volume pot. I'm considering doing the same to mine.
Sorry, folks, I usually insert the pics from my phone and then type in my comments on the computer--just easier for me.

Knobs are from Lee's Electronics in Vancouver, BC., and thank you.

Yeah, it's exactly a volume pot, and exactly for that reason. Do iiiiiiiitttt! But maybe between the 3PDTs so you can more easily adjust the knob with your foot. The pot makes the pedal 100% more usable for me, though. I just don't know if the IC between the 3pdts will leave enough clearance, and I also get nervous hand drilling around sensitive parts when I have slim tolerances for error, so I chose the side.
 
For anyone curious to know how,

Cut the board-out wire (not the jack-out wire) in the middle, take a A100K pot, solder a wire to pin 3 (leftmost looking at the potentiometer's butt inside the enclosure), solder the other end to the "old signal" wire coming out of the board. Put flux on both bared ends, hold them so they overlap, load a bead of solder on your iron, and touch it to the joint just enough to sizzle it, no more.

Solder pin 2 in the same way to the "new/volumed signal" wire going into the 3pdt, and pin 1, the rightmost one, to any ground point.

I like to situate and drill for the pot, and then size/cut wire and solder once in place.
 
That's a great idea. I'm going to have to add a volume knob to my build too. Good call
Yeah, dude. It was a mystery to me why that was lacking/omitted. I tried to think of a good reason, but in the end, I just decided I want to do this so I can use this.
 
Yeah, dude. It was a mystery to me why that was lacking/omitted.

The PDF-1 has no gain or volume control.
The PDF-1X has a volume control but no gain control.
The PDF-2 has a gain control but no volume control.

There are other small differences in the circuits between the versions.

The volume control in the PDF-1X isn't at the output, there is another gain stage after it.
 
The PDF-1 has no gain or volume control.
The PDF-1X has a volume control but no gain control.
The PDF-2 has a gain control but no volume control.

There are other small differences in the circuits between the versions.

The volume control in the PDF-1X isn't at the output, there is another gain stage after it.
Huh. Odd.

I wasn't meaning to imply it was omitted by you, I thought it was Stone Deaf. Still don't understand the [design] decision [by Stone Deaf], but I guess I can only speculate.
 
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A note for those thinking of building: can't find the tite chug setting any more, so maybe it was a figment of my imagination.

However, setting the cut/boost into cutting to me veers more into fuzz land and boosting more into more harmonically complex overdrive sounds. Might be more of an "into something" pedal than a standalone sound.
 
Thanks for the tip, man.

I wonder if I need to add a volume pot to mine.
Or can I just attenuate at the next pedal in the chain?
 
Thanks for the tip, man.

I wonder if I need to add a volume pot to mine.
Or can I just attenuate at the next pedal in the chain?
Definitely you can choke the signal by limiting with another pedal, but I prefer the finer control of the volume pot, especially because the output is so variable from a lot of volume to A LOT ALOTOFVOLUUUUUME. That way, you can choose how much gain to feed the next element. At the highest output settings, it might not be very usable going into other pedals/might just sound kinda crappy. I was guessing maybe the uncontrolled high output was left by Stone Deaf as a tube pusher type of idea, but even then, the variability of it makes that an odd proposition.
 
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Yeah, I think I'm gonna follow your lead and pre-emptively install a volume pot.
If I follow this into something delicate like a TC Electronic Flashback, I imagine it won't have the headroom to tame it without distorting the front end. Thanks again for sharing your discovery.
 
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