Mandroid, paranoid pitchdroid

[WormBoy]

Here is my Mandroid build. I was really anticipating this project as I wanted to dive into noisemakers again  . And this one surely delivers! Many different sounds to be had: lo-fi gritty detuned nastiness (don't expect pristine pitch shifting), tunable ring-modulator, etc. In 'robot' mode (step 8 on the rotary), you get a sort of rhytmic drone that can be tuned with the warp control. However, both speed and pitch will change together. The possibility to blend in the dry signal is really useful, that's really what makes the circuit shine for me.

A somewhat serious limitation is that it needs its own isolated power supply, which is a pain for my pedalboard setup. The 'vibrato' is rather weird, so that fits well with the oddity of the rest of the pedal (but not something I particularly like at the moment). The splode is interesting in robot mode, but that is something I have to explore further.

For my taste, this pedal really comes alive when you feed it an already distorted signal. With the internal gain trimmer maxed, it is still not enough for me. More distortion really smoothes out the nastiness, and let's it blend in better. This circuit might benefit from more gain (larger trim pot perhaps, or other diodes?) or a built-in fuzz circuit at the front. For now, I simply put a dirt pedal in front of it.



Gut shot below. The unconnected wire with the tie wrap is a ground wire from one of the switch pads. Forgot to remove it, but will just leave it there as it might come in handy whenever I decide to mod this thing.



Oh, and if you want to scare your kids: connect a microphone to the input and sing a lullaby 

[dan.schumaker]

Looks good, I might want to try the microphone trick 

[BrianS]

Nice loooking build.

[bsoncini]

Nice build.  Just started building mine. Just got back from a 3 week trip to Croatia. And I'm highly unmotivated. But this remotivated me.

What exactly is the microphone trick?

[WormBoy]

What exactly is the microphone trick?

Ah, the chip was originally meant for voice mangling. The pitch shifting can make you sound like a child or like a monster, or like a stuttering robot. So if you plug in a mic instead of your guitar it gets quite interesting.

[bsoncini]

Ah ok. The first electronic project I did was a voice changer with this chip for a friend. I thought there was some hidden mod or something.

[bsoncini]

I just finished mine today and had completely different results than you. I had to put the gain trimpot at zero or it distorted in a really nasty way. Only tried it with humbuckers so far. Maybe that's why.

[WormBoy]

I think it's supposed to distort in a nasty way  . There is no way to get a clean pitch shift out of it. That said, I had my build distort in a nasty way, as in sputtering, also on the dry signal. Turned out I had a bad opamp. After changing it I only had the expected nastiness.

[bsoncini]

Mine is distorted at zero. Anything more is like a broken speaker that pierces the ears. Tried it first with the neck pickup and sent my girlfriend running out of the room.

[stringsthings]

Awesome build!

[WormBoy]

Mine is distorted at zero. Anything more is like a broken speaker that pierces the ears. Tried it first with the neck pickup and sent my girlfriend running out of the room.

Sounds like it's working as it should  . Your dry signal should be clean with gain trimmer at zero, but the wet signal will be particularly nasty (the chip does not handle audio nicely, and cannot deal with dynamics). To my ears, it gets a lot 'better' with the gain trimmer maxed. It is a noisemaker, and it does make noise. However, with some careful tweaking and blending, you can get some more 'musical' sounds out of it.

[bsoncini]

After playing with this one a bit. I must agree with you that this sounds much better after a fuzz.

Also all the nasty distortion I had was better when playing with single coils

[culturejam]

Damn, that's a nice build.

[WormBoy]

Thanks guys!

After playing with this one a bit. I must agree with you that this sounds much better after a fuzz.

Also all the nasty distortion I had was better when playing with single coils

Yeah, it distorts in a rather nasty way, but it's not so nasty when it's blended in with some distortion in the input signal. My guess it that the circuit can be improved to use the chip in the most optimal way (and perhaps also getting rid of the isolated power supply requirement). However, the chip itself is pretty lo-fi, so maybe it wouldn't be worth the trouble. If you treat it like a noisemaker, this is a fun little project though, with some sounds you won't hear anywhere else.

[midwayfair]

sploooooode.

Great build.