The Analog Multi-Effects Processor: DIY gone too far?

[Juan Wayne]

VIDEO IN THE END, FEEL FREE TO SKIP THE STUPID STORY

(And yes, I'm very sorry for the title of the thread, I just had to do it)

First off, I want to blame the internets for this, but particularly this little slice of hell we call diystompboxes.com. You mother@#$%ers have done more harm than you could ever imagine.

Allow me to elaborate....

Everything was sort of fine with my life. I was enjoying my 15W solid-state Laney amp as usual, with my little Zoom 606 in the front, nothing fancy, I spent my money wisely and carefully... and then it happened, just an innocent little though: "What if I try to make a pedal myself?"

After all, I did notice the Zoom 606 lacked... something, especially when I applied my most recently discovered technique: the use of the volume knob.

So, as many may have done in my situation before, I started with Google. I wanted a Marshall-y kind of distortion, and since I was studying electronics but had not actually worked with them for a while, I thought it would be very beneficial to keep my soldering skills tight.

Everybody smiled as the narrator carried on with the story...

Well, after I narrowed it down to a couple pedals I found interesting, I tried to find out if it was common practice for other kind and selfless folk to post the schematics of these pedals online.

Then this happened:



LOOK AT IT! IT'S @#$%ING BEAUTIFUL!

That is what I call "Poosh!", my first build and still one of my favorite pedals. It's actually built into an electrical box, with the covers for the 1/2" pipes and everything.

Anyway, as most of you can anticipate, life as I knew it was over, and I have since inhaled so much lead smoke that I now produce buck-shot when I sneeze, but at least I have a pretty decent collection of pedals I really enjoy, right?

Now, if only it had stopped there. Not even close.

Since I wasn't happy with my electronics engineering end-of-career project/thesis at the time, I figured I would drop it and turn this disease into my new project.

Over 3 years and an insane amount of research and math later, this creature came to be:

This is a 100% analog multi-effects... thing.

This is how I became an engineer, by actually playing through this thing for the teachers.

This is my latest build, and I thought you psychos would find the results interesting.

There's no build hard enough when you really want to do it yourself.

Thanks for reading this far.

[radio]

I read your story, its really inspiring . However at work I can't look at videos

Would you mind posting a picture too, just if its not too much work?

Thanks for your story!

[Mark Hammer]

Interesting.  Rather than the footswitches engaging different effects or combinations, as one might expect, it engages different settings of the same set of effects.

I'm curious about how you achieve the different settings.  CMOS switches, digitally controlled?  Digital pots?

[bool]

That's how SRD rockmans did it - CMOS switching different settings and signal paths (mostly R-C networks).

[ElectricDruid]

We want schematics!! We want schematics!! <gathers rowdy crowd of DIYers with pitchforks and torches>

Excellent work, Juan. Nice to see some crazy digital along with the crazy analog. You're obviously a fully-rounded electronic engineer!

T.

[stallik]

Nice but all too familiar story here Juan. It's a great hobby (illness/addiction) fed by these wonderfully supportive pages. Now please put me out of my misery. Did you really go straight from the first pedal to this monster? If so, I'm grabbing the popcorn. This is going to be some show

[radio]

ok at home meanwhile, fa king crazy lol. Did you happen to see the Vfe multieffects by von Rutter

Looks like you have much in common.

[Juan Wayne]

First off, thanks a huge lot to all of you for your kind comments. I suck at taking compliments, I really do, if I heard someone tell me in person that something I did or said was "inspiring", I'd make some stupid and tasteless joke, after which you would all get to hear the echo that audible cringe is capable of producing. Seriously, it truly means a lot.

Stallik, you can put the popcorn down, I did not jump from that aberration I photographed straight into this thing. I had my share of practice building 8 completely different pedals including that one (plus some that I repeated and gave away), the latest of which is the phaser included in there, which would be a Phase 90 on all kinds of steroids. Also, I worked a couple electronics-related jobs.

I did use the exact same circuit as the pedal pictured, to the smallest of details, as the distortion pedal you hear in the video. It was my first build and I wanted it to be there, which is the true beauty of this thing. I wanted a particular effect in there so I just went ahead and did it, and I can do it with pretty much anything.

I was not familiar with the SRD and VFE you guys mentioned. There's probably some technology in common, but it's quite more complex than just one type of switching and digital control. For several reasons, some of which are legal stuff I won't even attempt to translate, I can't post the schematics for the time being (there's actually several of them, HUGE schematics by the way, along with hundreds of pages of additional documentation to it), or the specifics on the documentation itself.

But basically it is a mix of being able to engage multiple combinations of different circuits AND with different settings of those circuits, because one the frustrating things I found with conventional pedals is having to stick to one setting per effect, unless I wanted to have two or more of each, or crouch mid-song to change something, not to mention rewiring for rearranging them in a different order, cables, noise, power supply, kicking the knobs... all that is gone, all digitally controlled, but all purely analog on the audio path.

And the best thing is I still get to use the same effects (or new ones if I want to), and I'm unable to tell them apart.

Alright, this is getting long. Thanks again. You guys made my day.

[lion]

Very interesting and impressive!

..... I did use the exact same circuit as the pedal pictured, to the smallest of details, as the distortion pedal you hear in the video.....

Great sounding distortion.

If you don't mind sharing the distortion circuit I'd happy to know what it is?

Erik

[marcos_s_p]

Wow!!! Well done!!! Really impressive work!

Someday I wish I can do something like it. The distortion is also really nice sounding!

[marcelomd]

That is awesome!

And sounds really nice too!

Great job!

[diffeq]

Looks very impressive, good job. I like the chassis, very professional looking. Effect processing is even more impressive!

[Juan Wayne]

Thanks a lot!

The chassis doesn't look as good from up close, but it turned out way better than I expected and is as sturdy as could be, especially for a hand-made thing.

The distortion is a Crunch Box like this one:



Only a few slight variations were done: the Op-Amp is a TL072, R11 is 11k instead of 12k, probably because I had no 12k lying around at the time, VR3 is accessible as a second tone control which gives a lot of versatility, and my favorite, 3-way clipping selection with stock, none, and stock but with an 1N4148 in series with D2. Nothing fancy, but I spend most of the time on that last option.

Also, it has stupid gain which I never need, and it gets along amazingly with tube amps.

[digi2t]

The Poosh enclosure has "4ms" written all over it. 

Very nice!

[Juan Wayne]

The Poosh enclosure has "4ms" written all over it. 

Very nice!

I don't know, 4ms pedals aren't labeled with a sharpie, are they? Haha.

Thanks, glad you like it.

[lion]

Hi Juan
Thanks for the info on the distortion used.

Looking at the processor: ".. analog - digital - SRD and VFE - switching - processing ........" 

Is it just me not getting it (wouldn't be the first time)!  I follow it engages different settings of the same set of effects. But HOW are the controls SET and CHANGED?

I'm not after the details, just trying to understand the basics.

Erik

[Juan Wayne]

Navigation is pretty traditional, up/down to choose a bank with the footswitches on the right, presets 1-5 inside a bank with the switches on the front (that's what I'm doing in the video). As you can hear there, there no lag or audible silence, at all, I made sure of that before pretty much anything else.

It was hard to focus on the screen so I didn't really bother with it (plus, it's kinda boring to show), but it's all accesed from a very basic menu with the three rotary controls on the bottom of the screen (which are also switches if you push) and the three switches to the right of the screen, which are simply up, down and back.

So say you want to tweak the distortion, you go into editing the preset, go to the distortion pedal, then on that specific pedal the first three options will be gain, clipping type and volume, so you rotate as you would on a regular pot, then second row of options would be the tone controls. The phaser has its own series of options as well, I think it's intensity, speed, pahse stages on top, then bias, mix and feedback. The idea is that they should work as close to traditional pedals as possible, but without a stupid amount of things to push around. That's something I hate of most multi-things, too many options that do nothing for me.

Also, on the same screen you scroll for the pedal you want to alter, you can change the name of the bank, change the fx chain order, split into paralell chains at any point, swap pedals between chains A and B, sum chains at any point or send them to independent outputs, change the phase of one side if there's phase conflict between amps, engage the loops, move them around the chains, choose to solo a pedal to see how it works on its own... pretty much anything you can think of.

Then go back and save canges either on that preset or a different one (it'll show you the name of the one you're replacing just in case), that gets stored in the memory and then it takes you back to the main menu on that same bank you just saved and you're good to gig, or create/copy/tweak another preset.

I'm doing all this by memory so I'm sorry if it gets confusing, haha.

[potul]

Nice project

I guess that what we are all wanting to know is how you accomplished to digitally control the analog effects.

-Digipots?
-Optocouplers?
-Switch array?

That sort of thing...

Mat

[ElectricDruid]

+1 agree, I'm also very curious how you did the programmability. I know from my own work on analog synth circuits that making a circuit is one thing, but making a programmable circuit is another thing altogether. I'd say on average it makes for twice as much circuitry. Everything that used to be a pot has to turn into a DAC+VCA, or Digipot, or multiplying DAC, or 4051+lots of resistors, or whatever - all of which make the basic pot look simple!

Tom

[merlinb]

I guess that what we are all wanting to know is how you accomplished to digitally control the analog effects.
-Digipots?
-Optocouplers?
-Switch array?
-OTAs?

I guess we'll never know.