A friend brought me this old wah pedal that he wanted me to repair. I took the opportunity to trace the circuit. Here are a few pictures of my work. Click on the pictures to read more. Here is a quick demo I did with a distorted sound. I normally never use wah pedals, so this demo kinda sucks... :P Signal chain is: Gibon SG - NU-WA - Orange Micro Terror - 1x12 cab This is the schematic I ended up with. It's not confirmed yet. I believe it's correct, but the second transistor is not identified. More info: http://freestompboxes.org/viewtopic.php?f=19&t=25004
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I think what pleases me the most with this circuit is the small size. I managed to keep it very simple, just one dual op amp and a handful of components. With that said, I'm already working on a "deluxe" version with a front end gainstage (to keep it from getting too gated) and some filtering (to improve tracking) and that will probably end up twice the size. But for this version I wanted to keep it as barebones as possible.
My work area has moved and I have two new (to me at least) tools - oscilloscopes. :)
They are very useful, especially when designing your own stuff. Just a word of advice to anyone thinking of getting a scope - never buy one of those nano pocket scope, they are terrible. Here is another original creation of mine. This time it's a NAND Gate Oscillator chip that is mangling the sound. It's much milder and not as temperamental or unruly as the Raygun fuzz but it offers a few interesting sounds and a wierd modulation mode that goes into ringmod'ish sounds at higher rates. Very synthy. I hope you like it. :)
Here's another original of mine, the "Raygun Youth Chaos Fuzz". It's a very synthy and totally insane octave fuzz - an aquired taste for sure, but noise freaks should like it. :) It's loosley based on a circuit by Nicolas Collins from his excellent book "The Art of Hardware Hacking". A comparator turns the guitarsignal into a squarewave that triggers a Phase Locked Loop Oscillator. I could go on explaining how it works, but it's better that you just listen. This circuit works best with the neck-pickup and tone turned down on your guitar. In the video i'm using humbuckers (Gibson SG) and i'm playing the same riff over and over so you can get a sense of how the circuit reacts in different modes. The pot called "disorder" slows down the PLL tracking and goes from fast to slow. When tracking is slow it's mostly noise... The first mode is straight analog comparator fuzz and thus not effected by the tracking control. The name Raygun Youth Chaos Fuzz is a tribute to one of my favourite punk-bands. Yes, I know it's a bad pun, but I couldn't help myself... :) Aslo, the word Raygun is kinda fitting with some of the sounds it can make. Two thumbs up to anyone that understands the graphics play...
Here is an original design that I have been working on for some time. It's a combined vibrato and a stutter effect with minimum controls. I'm very happy with the results and I hope you like it. :) The idea is simple: the signal is split into two paths that are out of phase. One side is goes though a highpass filter (that cuts eveything below about 500hz) and amplitude modulation, then both signals are summed back together. As the two signalpaths partly cancel out from 500hz and up, this creates an interesting phasey sound in the crossover frequencies - a vibrato'ish sound that is a bit different from your standard tremolo. The stutter mode was added later as an afterthought. The way I set up the VCR (the JFET acting as a voltage controlled resistor) results in a very agressive amplitude modulation, so I wanted to take advantage of that in the design.
Tomorrow i'm going away for a few weeks, so I wanted to complete a fun build today - the Electric Mistress Flanger. It's a great sounding flanger, built on home-etched PCB. The original uses 18 volt and a SAD1024 chip that is hard to find / expensive. The layout I used (made by jorge r @ diystompboxes forum) is adapted for 9v and uses a common MN3007 chip insted. Original thread here. A recommended and fun build!
EDIT 2014-08-28 I added a PCB layout. I wasn't going to do a PCB layout for this one, but I needed the practice. :) So the pdf contains two different layouts if anyone would want to build it. I also moved the VERO layout to the bottom of the post. Here is something that is mostly just proof of concept. I was playing around with Craig Anderton's Comparator Fuzz, but I wanted to try a dedicated comparator IC insted of an op amp. It's probably tried and tested before, but I could not find anything on a LM311 based fuzz, only this thread that doesn't say alot. Anyway, this is what I came up with. It works well and sounds good. I need to think of a better name for it though.. :) At 0:46 I lower the guitar output for a very short decay on the notes. It's a very gated fuzz (all comparator fuzzes are). A good idea would be to put a booster in front with a volume pot to control the sustain and make it more friendly to low output pickups.
I built a small utility box today for testing and at first I wasn't going to post anything about this build, but I figured that it might help other people that are building pedals. How do you test your finished boards? This is my way. :) - Soldering pots and switches for testing seems like a big hassle and unnecessary work IMO. I test everything though a breadboard. Insted of pots I use small trimpots like these. I got a bunch of each for every value and I just pop them in - no soldering needed and it takes a few second to try another value (sometimes other values then the layout/schematic states works better). I make the leads a bit longer then necessary and trim them later when boxing. If some pots needs to be connected to each other that is easy to do with some short bits of wire. For hooking up switches I use wires with alligator clips like these.
Ringmods are probably my least favourite kind of pedal. But I spent too much time coming up with the oscillator for this one so I just had to box it. :) Turned out way cooler sounding then the Wolf Bagger pedal I made a while ago and it plays much better with weaker signals/single coils. I used my own layouts/design found here. Unlike many other Ringmod's this one has no carrier-bleedthough and generates a octave down on certain notes depending on how the carrier frequency is set. With the oscillator off if does a good job of creating a fairly strong octave up, especially with a fuzz in front. |