Aurora

[Paul Maddox]

Tony,

hehehe.... yeah... very cool with the four oscillators. actually,
> listening to the final example, at 3'58, i like that one too


Thanks, I feel four oscillators gives you plenty of choice :)
Two is just a bit to "weedy"
Three is nice but isn't an even number (ok, my OCD is showing),
with four you can run two pairs of sync'd oscillators slightly detuned for
example, which gives you that classic "sync" sound but with a nice warmth
and richness to it.
You can run three oscillators at the same octave, slightly detuned which
gives a nice full sound, but you can use the 4th oscillator with a sine
wave an octave below to really "beef" up the sound.

yeah. all these variants are different, especially the older moog ladder
> filters (i think the early ones used germanium pnp transistors) which sound
> different in each instance. i've always thought you hit upon a set of
> components that was particularly good, and distinctive.


ahh, thanks.
I'm using BC549s (NPNs) with opamp input summing and output instrumentation
amps.
My theory being, the opamps give you a nice clean sound into, and out of
the filter, i.e. they don't mess with it, but you leave the filter core
(the transistors) well alone, let the "tone" come  from the filter..
I've also got a slightly non standard biasing on the transistors, so I'm
pushing them a little more than normal, people tell me it won't work, but
it does :)
The VCAs, well they're as clean as I can get them without adding a tonne of
extra parts, I don't use the output transistors on the LM13700s as I think
the "colour" the sound to much.
Again, the only colour I want in the sound is from the filter.


> makes all the difference: distortion within the filter is fundamentally
> different from pre or post distortion, given some level of resonance.


I've not tried the distortion with resonance yet, once I increase the
resonance a little more I'll give that a whirl, thanks :)

Paul
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