[sdiy] Mod wheel/other stuff.

[john mahoney]

While there is overlap between this list and some bender lists, a quick
definition for DIYers who don't know what "bent" means (in this context :-).
Circuit bending is basically what we call "modding." If you aren't aware of
this subculture, do some Googling on "circuit bending" or "circuit bent" and
you may be inspired (or disgusted!) by the things that people -- often
technically ignorant people -- can do to poor, unsuspecting instruments and
toys. There is some interesting stuff being done, but of course 90% of
everything is crap.

Ethan, your bending questions really belong on a bending list. But,
anyway... There is more to the sound generation than just resistors and caps
(unless you are just hearing AC buzz or hum). Many of the toys have custom
or semi-custom sound ICs in them, a "black blob" chip that does a lot of
things (hard to bend those).

Some older toys and all the bent Theremins out there use very simple
555-based tone generators. Google "555 oscillator" and "555 tutorial" for
more on the amazing 555 chip.

A mod wheel is just a pot with a "wheel" for a knob. It sits near the
keyboard, usually to the pitch bend wheel/lever/etc so the player can add
MODulation. The classic mod source is an LFO and the destination is the
pitch; this adds vibrato. Many sources and destinations are possible and
some of those are actually useful. ;-) Filter cutoff and PWM are other
common things to modulate.
--
john


----- Original Message ----- 
From: "ethan tripp" <ethan at monsoonmicro.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Wednesday, September 10, 2003 12:24 PM
Subject: Fwd: [sdiy] Mod wheel/other stuff.


> > interesting ideas. i was thinking of it yesterday for a while. i could
> > certainly rig it. lord knows i do a lot of rigging. but i was actually
> > looking for replacement pitch wheels (thank you). btw, what does the
> > mod wheel do? remember, i'm new to this, i don't own a synth, and have
> > never worked on one. hopefully we'll change all of that.
> > so anyway, i did find a site that said it had a replacement for 7 usd.
> > no pix though, and i don't like buying things sight unseen. i was just
> > wondering b/c there is a popular bend you can do on casios (and just
> > about anything else, to get a good pitch up/pitch down. people who
> > i've been talking to about modifying things have been asking about
> > pitch wheels that return to true pitch position automatically. so i
> > thought i'd ask.
> >
> > other stuff:
> > i have noticed in a lot of toy's that i've bent, that certain
> > connections on the board produce non sample based tones. meaning they
> > squeal like a pig if you touch them (naughty) in the right place. if
> > you connect the bend to a pot, you can get a huge range.
> > my question is, is it a sort of accidental tone producing circuit that
> > can be reproduced? we talk a lot about oscillators and tubes and
> > whatnot, but this thing is making tones with just resistors and caps
> > etc. can this be replicated? anyone know of any simple sound
> > generating circuits?
> > by simple, i mean 12 or so parts, and no chips.
> >
> > other other stuff:
> > i'm looking to build a vco. my first. cost, unfortunately is an issue.
> > so, what do you guys think of this?
> > http://www.ele4music.com/vco4d/vco4d.html
> > or are there any other inexpensive solutions that you guys have built
> > or can recommend. bear (is that right?) in mind that i've never done
> > this before. i'd really like to start a box o' modules. something i
> > can work on over time, adding modules as i can afford them.
> >
> > thanks,
> > -et-