Random Number Generator

Austin73 · October 16, 2006, 06:01:26 PM

Just looking at Tcobrettis layouts and noticed the Random Number Generator. Just wondered what is actually is?

Is is a Fuzz/Noise maker?

Cheers

Aus

smnm · October 16, 2006, 06:55:11 PM

OH the shame!
I built this a couple of months ago and never got round to doing a build report. It's one of Doug Deeper's early mid-fi pedals, I emailed him and he sent a verified schematic, which I uploaded to Experimentalists Anonymous with his permission - see http://experimentalistsanonymous.com/diy/Schematics/Fuzz%20and%20Fuzzy%20Noisemakers/Random%20Number%20Generator.jpg
There's another version on there with 2 pots, but with some errors.

It's a v extreme high frequency fuzz, fuzz on fuzz with extra glitchy overtones that are fairly random, hence the name. There's a sound clip on the mid-fi site. I had a lot of fun trying umpteen different transistor combinations - can't remember what I ended up with, but it's worth experimenting - I did decide that the first one should be relatively low gain, so there's a liitle more control further down the line, although control is not really what this one's about. I like it. If your a fan of Tim Escobedo's PWM and Uglyface, you should like this one too.
Easy quick build - I did mine on perf pretty much following the schematic.

KerryF · October 16, 2006, 07:09:17 PM

smnm- You have the schematic for the Mid-Fi Pitch Pirate?

tcobretti · October 16, 2006, 08:28:35 PM

It shifts the pitch of the note based on how high the gain is going into the pedal. The way it shifts the note is mostly by octaves, both up and down, and it's not exactly random. You can change the effect slightly by changing the position of the volume knob on your guitar. It is very weird and almost completely impractical. I plan to build it, a Bronx Cheer, and a Atari Punk Machine into an old Roland GR-707.

BTW, that vero layout is verified.

Marcos - Munky · October 16, 2006, 11:35:31 PM

The 2 knob version have only 2 differences from the one knob version:
- the 10uF/1M in parallel is not present in the 2 knob version. Instead of it, there's a 0.01uF cap in series with a 10uF cap.
- the 100K resistor in the feedback loop (the one near the "2N3904", the bottom one) is a pot wired as a variable resistor in the 2 knob version.

Don't know if there's any errors in it, built it as the schematic I have and it worked fine. About the Pitch Pirate schematic, I believe there's no schematic floating around for it and for other Mid-Fi effects (besides the ones Doug posted here some time ago).

tcobretti · October 17, 2006, 12:01:51 AM

What does the 2nd knob do?

I hadn't heard about the 2 knobber or else I'd have tried it!

smnm · October 17, 2006, 04:39:54 AM

Quote from: call1800ksmyazz on October 16, 2006, 07:09:17 PM
smnm- You have the schematic for the Mid-Fi Pitch Pirate?

Doug gave me the schematic on the basis that it was one of his older designs and not currently a hot seller, the Pitch Pirate would be a different matter, but you could still ask him politely - he's posted on here few times recently.

Quote from: tcobretti on October 17, 2006, 12:01:51 AM
What does the 2nd knob do?

I inserted a 2nd pot (100K) in the right position but without making any other changes, so it doesn't do very much, I might go and look at the v1 schematic again (it looks confusing though, so I didn't check it for differences with v2)

re 'randomness' - this is a YMMV pedal for sure - my one definitely gets some weird fizzly artefacts as the the note decays, and the octave-ish effects are v unstable (with a bit more/ a bit less according to the 2nd pot position), but random is probably too specific a term for that - a lot depends on the transistors - many variable factors! I think this would work well with bias pots on a couple of the trannies for more messing. One other thing about is that it's VERY LOUD, and the sound changes as effect volume increases (and you turn your amp way down).

Use the search too, there are some posts by Doug when he was originally working on it /just finished it in 2003 that are interesting. I guess I got interested in it because I liked the sound of the Glitch Computer.

mr.adambeck · August 02, 2009, 08:41:43 PM

Sorry to open up an old topic, but I wanted to build this based off of this layout by Dragonfly:

However, neither Small Bear or Pedal Parts Plus sells PN2222 transistors. Any suggestions on a good replacement that's easier to get? Will a 2N2222 be good? I'm a noob here, so I don't know what I'm looking for.

frank_p · August 02, 2009, 09:13:30 PM

Quote from: mr.adambeck on August 02, 2009, 08:41:43 PM
However, neither Small Bear or Pedal Parts Plus sells PN2222 transistors. Any suggestions on a good replacement that's easier to get? Will a 2N2222 be good? I'm a noob here, so I don't know what I'm looking for.

Yep,
I think they are the same: 2N2222 was normally metal cased the other is TO92 plastic casing.
"X"N2222 are available about anywhere as they are one of the "most standard" transistors.
Any "normal" suppliers should sell them.

Here you are:
http://www.datasheetcatalog.org/datasheet/MicroElectronics/mXrurvs.pdf

rousejeremy · August 02, 2009, 09:28:59 PM

You're going to love this build. It's INSANE.
http://www.youtube.com/watch?v=4r6A6rqI9xo

Quote from: mr.adambeck on August 02, 2009, 08:41:43 PM
Sorry to open up an old topic, but I wanted to build this based off of this layout by Dragonfly:

However, neither Small Bear or Pedal Parts Plus sells PN2222 transistors. Any suggestions on a good replacement that's easier to get? Will a 2N2222 be good? I'm a noob here, so I don't know what I'm looking for.

doitle · August 02, 2009, 09:47:48 PM

mr.adambeck · August 03, 2009, 01:28:32 PM

Quote from: rousejeremy on August 02, 2009, 09:28:59 PM
You're going to love this build. It's INSANE.

I hope so! This is my first build of something more non-traditional (building more odd/strange pedals was my original motivation for pedal building in the first place, so...). Other than this it's been volume boosts and traditional fuzzes.

rousejeremy · August 03, 2009, 01:45:14 PM

I found a slightly smaller vero

mr.adambeck · September 17, 2009, 05:46:54 PM

Hey, from looking around I heard people mention a two knob version of this. Anyone know how to adapt the layout to have this? And has anyone verified either of those layouts... I've run into trouble in the past with non-verified layouts

I'm going to start on this over the weekend! Really excited!

Top Top · September 17, 2009, 06:22:53 PM

I recently built it from the vero above (the smaller one), though I built it on perfboard point to point following the layout... No problems with the layout here.

I think there were two versions of the "two knob" version floating around. One was the first version that appeared I think, which Doug said in an old thread was incorrect. Then there was a new one, which, as far as I could tell, had only one difference from the 1 knob version, which was a 100k pot in place of the 100K resistor at the bottom right of the schematic, or I believe, dead center in the smaller vero above (the one that is connected, via the jumper near the right side, to the collectors of the 2nd and 4th transistors). Perhaps someone will correct me on that, I don't have it in front of me.

I built this version of the two knob version, and the second knob controls the intensity of the weirdness. When it is open all the way (0 ohms), you pretty much get unpredictable bogged down 8bit sounding noise. When it is up (100k), you get a the jumpy octave effect. For me, the knob definitely is worth putting in and allows a few different types of sounds. I can even get a fairly reliable octave down out of it for at least significant areas of the neck with my tone knob and the setting of the 2nd knob set correctly.

It is noisy, but my build isn't completely tuneless. You definitely don't want it in place of a regular fuzz box, but it can be used in a melodic (though weird sounding) way for videogame-like sounds.

This is one build where socketing the transistors is definitely a necessity. I had to mess around with a bunch of them to get a combination that allowed proper gating of the sound when not playing, while also providing a good amount of weirdness. I didn't have the 2N4401, so perhaps if you built it exactly to spec, you could expect it to work well right off the bat.

mr.adambeck · September 17, 2009, 07:19:27 PM

I just finished building the red vero layout, but haven't tried it out yet. I built it to spec except for instead of pn2222 I used 2n2222. I got to wire it up and try it out. I'm going to try to figure out how to get the 2nd knob in the layout I used too. Thanks for the help.

earthtonesaudio · September 17, 2009, 08:00:43 PM

Quote from: tcobretti on October 16, 2006, 08:28:35 PM
It is very weird and almost completely impractical.

I read this and thought: Build one NOW! No, wait, BUILD THREE! NEVER TURN IT OFF!

Perhaps a bit too much coffee...

rousejeremy · September 17, 2009, 08:32:25 PM

I love my RNG! http://www.youtube.com/watch?v=4r6A6rqI9xo

Top Top · September 17, 2009, 08:43:00 PM

Quote from: mr.adambeck on September 17, 2009, 07:19:27 PM
I just finished building the red vero layout, but haven't tried it out yet. I built it to spec except for instead of pn2222 I used 2n2222. I got to wire it up and try it out. I'm going to try to figure out how to get the 2nd knob in the layout I used too. Thanks for the help.

I actually just ended up leaving my 100K resistor in there and soldering a wire in at each side of it and putting the 100K pot in parallel with the resistor because I built it without the knob at first and my layout was too crowded to go through the trouble of taking the resistor out.

mr.adambeck · September 17, 2009, 08:45:46 PM

Top Top - Maybe I'll try that. Mine sounds pretty good, but isn't gating like it seems to in other peoples clips. It gets a crazy "whishing" noise after I let go of the notes. Occasionally it gates, but mostly I get the "whiiishhhh" and then a ton of awful feedback. Would adding the second knob help this?

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Random Number Generator