[sdiy] Novation Bass Station 2
stewpye at optusnet.com.au
Wed Jun 5 23:05:42 CEST 2013
I drew a circuit on paper to do this a few years ago but can't find it.
It's basically like this....
Use a flip flop (probably driven by the saw reset pulse) to get a square
wave half the frequency of OSC 1, This is the 1 octave down square output.
Use this square wave to level shift every second saw up. I think you
should be able to do this, and level shift back down to centre the
waveform around 0V, and reduce the gain to 0.5 all in one inverting op
amp stage. The saw wave will be one input, the 1/2 frequency square
another, and the DC level shift another.
Use standard sine shaping to get the sine. I'd use an LM13700 to get
both sine waveforms.
Use a standard comparator PWM circuit to get the pulse wave.
Repeat the process to get another octave down, however this time the
flip flop is driven from the output of the first flip flop.
If that doesn't make sense I can draw a schematic when I get home. I'm
just about to leave for work.
On 6/6/2013 6:11 AM, Tom Wiltshire wrote:
> Hi All,
> The Novation Bass Station 2 claims to have two analogue oscillators + a sub oscillator. The sub osc can be tuned one or two octaves below Osc 1. It offers Square, Sine, or narrow pulse.
> Would anyone care to suggest ways that could be done?
> I can't figure it out, or rather I can only see convoluted ways which seem highly unlikely in a commercial instrument. No particular reason - I'm just curious about other people's synth designs.
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