my casio SA-2..
more, better and bigger pix
here.i'll do a write-up on the details asap, but as far as features go:
- brought out all 100 SA1 sounds.
- 5 drumsounds.
- feedback bend (dj synchro's screamer).
- tone shift switch, down = more bass fixed, up = gradual thru touchpoints, mostly for use with the feedback bend.
- 2 crash buttons.
- pitch drop, touchy bugger, will cause crashes when overdone. works great when it's already crashing though.
- blue led on a bendy arm, driven by a square wave LFO, and 2 LDR's to point the led at.
one for the pitch - instant optical vibrato - and the other for modulating either feedback level or output volume.
- insert jack, splicing in between the sound generation chip and the poweramp.
about the insert jack:
i noticed most fx pedals don't like the full output of the SA series, but the unamplified soundchip output works a lot better.
i did want to keep the amplifier chip though, because the unamped signal is too weak for using it with synth modules, for example.
about the crash buttons:
i tried ghazala's aleatron glitch bend, and although i really like the results, i found it to be way too unreliable.
it's nice for recording and sampling, but live use.. it freezes the keyboard up way too often.
but then, basically what he's doing is making the chip miss a couple of clock pulses
so i wired up my pushbutton to some CMOS ic's to generate just a small spike everytime it gets pushed.
length of this pulse is fixed, no matter how long you hold down the button.
now i have this pulse control a CMOS switch, that hooks together the same bend points, interrupting the clock for just a few milliseconds.
turns out it's super reliable.
maybe the results are a bit less dramatic. then again, it still does do the aleatoric music every once in a while, and it doesn't hardly ever freeze up as often, so it's definitely a keeper!
schematic coming soon, needs cleaning up.since i was using a 40106 for this and i had me a spare inverter on there, that one got turned into the square wave oscillator driving the led.
the whole thing is built into the case of a broken record player, still using the original speaker with a home made amp circuit.
- button on the left of amp is on/off switch and master volume
- button on the right is preamp gain
- when driving the preamp into clipping, some yellow leds illuminate the speaker front, which i sprayed white to enhance the visual effect
i might have a bit of a volume knob overload here (keyboard out volume, preamp, master), but if i use the keyboard out with another amp or ext. synth input i like having the keyboard volume.. and the preamp clipping sounds completely different from the feedback distortion, so i use that quite a lot. and that means i may have to turn down the master volume a little..
still needs minor tweaks, and some switches need replacing, but so far i'm really happy with how it came out.
