Ridiculous Fuzz Idea

[jacobyjd]

Hey, so I was just looking at the WMD Geiger Counter fuzz, and I had the following thought:

What is the next step above something like a tricked-out fuzz face (yes, Fuzz Factory, I'm looking at you)?

A uC-editable circuit that allows you to adjust the parameters of the 4 resistors (and the caps, why not?), with the ability to save presets. In all reality, this looks like something Etienne  (cloudscapes) would be able to pull off.

Essentially, one would be able to adjust all the parameters of the circuit (I'm guessing this could be done with no more than 2-3 pots/encoders/pushbuttons/whatever), then save to one of n banks. This way, the circuit could be less tweak-y in a live situation, but still allow you to almost infinitely adjust everything.

This could use either Ge or Si transistors--it wouldn't really matter. The programming should be limited to values that would not damage the transistors, but would allow plenty of variety.

Eh, it's just a thought, and I figured I'd get it down before I forgot it

[JKowalski]

You need a digital-to-resistance converter, digital pots would work the best for that, I think.

Then a uC.

Then an analog multiplexer if you want to switch out capacitors.

And some coding, not really that difficult. It's totally possible but I don't think it would be worth it really. As cool as the idea sounds I think there is a limit where usefulness becomes novelty. *shrug*


You'd probably want some kind of display system, LCD would be best, because you'd want to see the names/numbers of the presets and the values of the components you selected. Navigate the system with some kind of button system and change the values using an encoder.


It's like a DSP modeler but through analog means. If you are thinking along these lines it might be best just to go completely DSP for the practically limitless options it gives you without the very complicated system of ICs...?

[Strategy]

Interesting, wasn't there actually a Digitech digital distortion, in their classic PDS series (think those double pedaled-rectangular boxes, mostly known for the delay-and-hold models), that you could store presets on?

I have no idea what a schem of one of those looks like - and honestly can't remember what they sound like? Sounds like a $30 eb*y purchase to me!

- Strategy

[Strategy]

I think this is the one:

http://www.effectsdatabase.com/model/digitech/pds/1550

fun!!

(I love this era of Digitech, crappy but also awesome..)

- Strategy

[cloudscapes]

It is indeed possible!

I wouldnt use a digital potentiometer though. Most of the ones I've seen are less than 256 steps (pot placements) and fuzzes can be sensitive. I'd use a 12bit DAC driving a fet or a vactrol.

[JKowalski]

It is indeed possible!

I wouldnt use a digital potentiometer though. Most of the ones I've seen are less than 256 steps (pot placements) and fuzzes can be sensitive. I'd use a 12bit DAC driving a fet or a vactrol.

I suggested a digital pot because the idea of presets kind of meant "set and forget" to me, i.e. you won't be moving the pots much except for when you are setting up a preset to store. If the pot is stuck in one position during the time you are playing that shouldn't be a problem. It will be a lot more reliable and consistent too, I would think, as it is wholly reliant on digital settings without any of the analog iffy-ness FETs and vactrols have.

And I don't think precision over 1/256th of the "rotation" is totally necessary. Plus, you can get 4 pots in one IC 

[Rectangular]

I think this is the one:

http://www.effectsdatabase.com/model/digitech/pds/1550

fun!!

(I love this era of Digitech, crappy but also awesome..)

- Strategy

I love that early 90s digitech/DOD era, so many great boxes, lots of weird ideas.

[arawn]

Hey I had a digitech very similar to that but it was red and had some buttons as well
bunch of factory presets, and a bunch of banks for storing your own. You could model almost any distortion made up to that time with it
I miss that thing a lot

[Taylor]

If you are thinking along these lines it might be best just to go completely DSP for the practically limitless options it gives you without the very complicated system of ICs...?

This is kind of what I was thinking too, but having messed with doing some DSP distortion I have to say that it wouldn't be trivial at all to make a digital Fuzz Factory.

[jacobyjd]

If you are thinking along these lines it might be best just to go completely DSP for the practically limitless options it gives you without the very complicated system of ICs...?

This is kind of what I was thinking too, but having messed with doing some DSP distortion I have to say that it wouldn't be trivial at all to make a digital Fuzz Factory.

Exactly--that's why I was thinking in terms of using the DSP to edit the parameters, rather than create the entire circuit.

Essentially, it would make it 'easy' to have almost every fuzz face derivative at your disposal in one box, with available bells n' whistles.

[devi ever]

It's been my dream to eventually make a devi-everything pedal that was analog at it's heart, but you'd be able switch between each devi ever circuit using a digital routing system (most of my fuzz's are built around four basic circuits).

I'm assuming this is the kind of things you guys are talking about here.  

If so.  Just rad.  I'm still light years away from getting into this kind of thing... more than likely will hire someone else to do it when I have the capital.

... but yeah, just wanted to drop in and say mad respect to this project!  

[aron]

I have that exact Digitech but something's wrong with it. It sounds terrible. Much better is the Ibanez PDS series. Killer! I have one on my pedal board.

[Processaurus]

Ever see the Sansamp TRI-AC?  It's a sansamp GT2 digitally controlled to have 3 presets, that you get with 3 radio pushbutton style footswitches.

A lo fi but very doable way to get what you want is to tear apart a Tri-AC, locate the digi pots, source the right values from the same series, tap off the control line for each digipot, and run that to a separate board with your a fuzz face on there with its respective digipots.

That would be a great kit if anyone in the kitting business were interested, to make a non specific pedal wrapper that had several memory slots for settings on a bunch of pots, as well as physical pots/switches to program it, as well as a few footswitch inputs. 

An analog version that's been suggested here would be to use a bunch of trim pots for the different "presets", and select them with CMOS 4052's (DP4T) or 4051's (SP8T).  That approach would be much easier for a smaller number of presets, but would start getting to be too many parts if you wanted a bunch of presets.  But most pedals don't really have an infinite number of useful, distinct sounds.  I like about 4 on the fuzz factory.

But if someone could program something like that it would be flat out amazing.  Digital control of analog circuits is a great future for pedals.

[Processaurus]

Hmmm, here's a Russian schematic (compressed in the RAR format) of the Tri-AC, but without the PIC section or the user controls, still interesting, they used discrete FET's for all the switching.

http://amtshop.com/sxema/SansAmp_TRI-AC.rar

[potul]

Are you sure this is the rall TRIAC schem, or just an attempt to do something similar? I see some switching controlled by a PIC, but no digital pot or similar, and the original TRIAC is storing the pot positions as well.

Anyone who reads russian could translate the comments in the shcematic?

Thanks.