In general, Yamahas don't offer the glitch capabilities of Casio keyboards, but as far as I can tell, their two speakers are amplified semi-separately - I assume this is done purely for signal strength, as the keyboard only normally plays in mono. The distortion bends I added to this keyboard - a bend I frequently use to make oscillator tones using the amplifier and surrounding components as the oscillator - sound very loudly in the right speaker, and just a little bit in the left. I wired separate 1/4" outputs for each speaker to take advantage of this situation. Unfortunately, I don't have a mixer with me, so you can't hear the result in this recording: http://boconnell.web.wesleyan.edu/yamaha.mp3
This keyboard is only a foot or so across, and the circuit board is about an inch square - not too many bending possibilities on a "black blob"-type one like this, so I just added a clock speed mod by unhooking the resistor that controlled it and wiring it in series with a pot. I added two body contacts that take advantage of human voltage to distort the signal a little bit, too. http://boconnell.web.wesleyan.edu/rainbowkeyboard.mp3
1.Build an Echorec. From what I can tell, this things never caught on but seem a lot, a lot cooler than the more popular and well-known Echoplex. I'm planning to build it onto an old turntable.
In addition to circuit bending, my main interest for the past couple years has been tape delay techniques, using reel-to-reel players. I currently have three reel-to-reel players - they are rather hard to find for cheap, but if you look around at thrift stores, junk lots, etc. you will eventually find some - I got two from my uncle, one for $10 from a school that was being abandoned and having a tag sale, another in a neglected back room of a junk shop in Middletown CT for $10, and one for free from the electronics dump at Wesleyan. The techniques have been around since the 60s, pioneered by a lot of people, but mainly Pauline Oliveros. In her excellent book Software for People, there's a great essay detailing many of the same tape delay techniques I figured out myself. Essential listening is Electronic Works 1965-1966, particularly the track Big Mother Is Watching You (preview here).
The most basic setup for tape delay involves two reel-to-reel players on the same reel of tape, with one set to record from a mic or whatever, one to play, and the play signal looped back to the record head.
In this most basic setup, the sound is simply delayed based on the length of tape between the heads. If you're running tape at 7.5 inches per second (ips), this can turn into a sizeable delay with the reel-to-reel players not too from each other.
The setup I currently use in performance, which works on the same basic principle as the basic setup just described, is considerably (unnecessarily?) more complicated.
I use 3 reel to reel players, usually with no input, but in a closed feedback system, analogous to mixer feedback like this:
or pedal chain feedback in the noise world. Sometimes I use a mic to yell into, which becomes completely unitelligible processed through my system. My basic interest in this system, however, is in the tape players themselves, and their internal sounds - hence the feedback loop. The guitar effects pedals give me additional possibilities, but the source sound comes from the reel to reels themselves - specifically, the cheap, discard-type reel-to-reels I use - no pro gear here.
Myspace of my band Jock Jams in which I use this setup (playing with a guy doing a lot of circuit bent stuff and more pedal complicated feedback loops than I use)
