DJ TOY THING (aka DJ Crappy Turntable)
DJ Crappy Turntable: VIOLATED!
El MuCo has begun work on a number of one-off instruments, one of which is briefly described here. This fantastic pile of crap was once a DJ toy whats name I have forgotten, but will refer to as the DJ Crappy Turntable or DJCT for short.
This instrument had two “platters” on the top side (not shown) made of ridge plastic and attached to the instrument with screws. On the underside of the platters were gently sloping ridges which, when the platter was turned, would cause buttons which were inserted in the holes (visible in the lower-right side of the picture in the black part of the case) to be pushed in. This would close a part of the circuit and cue a short audio clip which would make a squeaky “DJ” scratch noise, or another amusing sound such as a dude yelling “Hit it!” in the style of Bad Dudes. (dating self here.)
The instrument has a dearth of good bends, but after a few goes we were able to find several points on the board that connected to the amplifier circuit that, when engaged, would give either an ear-piercingly high wail, or a low cosinish-sounding moan. The below pic shows these two points.
A bend (the only) on the DJ. Note the red clip bridging/touching two resistors
When testing the bend by running the sound into a computer and recording it, we severed the connection to the speaker. The result was that the bend no longer functioned because the speaker itself supplies a certain amount of resistance. By replacing it with a 4.7 ohm resistor, the bend was once again functional.
The speaker resistance replaced with 4.7 ohm resistor.
Here is a recording of the bend in action.
Here is a fantastic sonogram of the first 12 seconds of the sound file. Please note DC has been removed 😉
The first 12 seconds of the above sound recording
This instrument suffers from what a lot of more up-to-date instruments suffer from — a lot of surface-mount resistors, and complex digital ICs without a lot of analogue leads. The result is that, more often than not, newer toys end up having one, maybe two good bends. Usually the built-in sounds are intolerable, and the bends involve tweaking the timing circuit down to the point that the sound is unrecognizably low/slow, or bending something in the amplifying circuit which results in distortion/masking of the original sound.
Neither of these is a particularly worthwhile or rewarding endeavor if the original sound wasn’t worth a damn. However, sometimes one can find bends that result in original sounds, in other words, not part of the IC programming. In this particular case we have some potential. A touch sensor may be employed to give us a little more control than the potentiometer in use (100k). But the end result will be an instrument with very little sonic flexibility.
Our next project will be to start housing these “one-off” instruments in modular patch-bay style housings where boxes will contain more than one instrument, and all of the connections will be made to a separate control box where we will have touch-sensors, potentiometers, etc.