[sdiy] Novation Bass Station 2

Stewart Pye stewpye at optusnet.com.au
Wed Jun 5 23:25:00 CEST 2013

You'll also have to shape the octave down saw into a triangle before 
going to the sine shaper. The way I had planned doing it was to invert 
every second saw cycle to get a tri wave of half the frequency of the 
original saw, as I was mainly interested in sine sub octave waveforms.

Oops, I just re-read the original post and it doesn't mention saw waves, 
so instead of level shifting every second cycle invert every second 
cycle so you get a tri wave of half the frequency. An optional inverter 
circuit and an analog switch could be used for this.


On 6/6/2013 7:05 AM, Stewart Pye wrote:
> Hi Tom,
> 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.
> Regards,
> Stew.
> 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.
>> http://uk.novationmusic.com/hardware-synths/bass-station-ii/the-synth-engine-a-brief-overview 
>> 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.
>> Thanks,
>> Tom
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