[sdiy] Re: anyone have some creative mods/addons for a 303? Devilfish style?

[Amos]

I have been looking over the schematic and collecting suggestions for
x0xb0x mods myself.  Several replies in the ladyada.net x0x forum
contained additional mod suggestions, like where to attach a switch
for costant slides between notes (infinite sustain)...

I believe you can replace the waveform switch (saw/square) with a
three-way switch, and wire the mix in jack to the middle position...
this will give you saw, square, or line-in thru envelope and filters. 
 This will let you use the x0x as a programmable beat-synch'd
filter...

I will post whatever I can find to this list... also I would love to
get feedback on some mods I have in mind.. to see if they make
sense/are likely to work.

-Amos

On 9/15/05, Danjel van Tijn <danjel at gmail.com> wrote:
> HI,
> 
> A group at MIT reverse enegineered a Roland TB-303 and sourced most of the 
> original transitors and components. They also added MIDI and USB 
> functionality and some other features. AT it's root is is still a 303, the 
> schematic even uses the same designations as the original 303 (e.g. R110 of
> 
> x0xb0x = R110 of TB303).
> 
> On the site are a few simple mods such as adding a pot to adjust slide time,
> 
> changing enevelop depths and increasing resonance...all of these are failry
> 
> basic.
> I have been interested to add some mods that will really allow me to "mess"
> 
> up sounds. I think the Devilfish Mod for the 303 had some great ideas such 
> as using the VCA output to modulate filter cutoff.
> How would I implement that? I know I would probably be connecting the VCA 
> output via a 100K resistor and then a 0.47uF cap (so that only audio 
> frequencies are passed to the filter). Where would I connect it? (I have 
> included links to the schematic below). I would also want to use a pot to 
> control FM amount.
> 
> Also, what are some other cool mods I could do? I was thinking of having the
> 
> VCO output feedback into it's CV input (like operator feedback in FM 
> synthesis) so that I could get a noise source. Again I would control that 
> feedback with a pot. 
> 
> Another idea I had was to put a small ring mod board in there and have an 
> external audio input be the modulator or perhaps put a small LFO inside.
> 
> Any other ideas? I am new to this so the mroe details the better!
> 
> 
> http://web.media.mit.edu/~ladyada/make/x0xb0x/files/mainboard_beta.png
> 
> http://web.media.mit.edu/~ladyada/make/x0xb0x/index.html
> 
> 
> thanks!
> 
> 
> Danjel
> 
>