Yes, I have that set of Yamaha engineering notes. In fact, that page
you indicated was my primary guideline for the discrete version. I think
the reset pulse is to guarantee a full waveform reset (full capacitor
recharge) at the higher frequencies such that the pitch doesn't start to
go flat.
That page also shows why tracking of the VCOs is such a pain; the
transposition setting resistor (Rft) has to be exact for each desired
octave, which is why there are trimmers for each one. If the Rft value
for a given octave is off even slightly, the tracking goes south.
I have my prototype CS VCO running into my production CS filter. It
sounds very nice. :) I'll record some audio clips this weekend.
In other news, I built and tested the NE11000 VC-BPF as used in the
GX-1, and it works great..except that I wired the resonance pot backward.
(The original NE11000 did not have a variable resonance control; it only
had a trimmer that was set and sealed for a Q of 4 or so).
Crow
/**/
you indicated was my primary guideline for the discrete version. I think
the reset pulse is to guarantee a full waveform reset (full capacitor
recharge) at the higher frequencies such that the pitch doesn't start to
go flat.
That page also shows why tracking of the VCOs is such a pain; the
transposition setting resistor (Rft) has to be exact for each desired
octave, which is why there are trimmers for each one. If the Rft value
for a given octave is off even slightly, the tracking goes south.
I have my prototype CS VCO running into my production CS filter. It
sounds very nice. :) I'll record some audio clips this weekend.
In other news, I built and tested the NE11000 VC-BPF as used in the
GX-1, and it works great..except that I wired the resonance pot backward.
(The original NE11000 did not have a variable resonance control; it only
had a trimmer that was set and sealed for a Q of 4 or so).
Crow
/**/
On Fri, 27 Aug 2004, David Rogoff wrote:
> I just found this site:
> http://home.debitel.net/user/jhaible/cs80_vco.gif. Apparently, the
> weird pulse is done on purpose!
>
> David
