The ASM VCO tracks well at High Frequencies, at least the ones I
have built are good in this regard.
BTW, not sure if this helps, but, Magnus Danielson suggested to me, when I
was building ASM VCOs (very similar in their core design to what Ken has),
to put a 10K multiturn trimmer between the 150K resistor and V++ (R15 on
the ASM pages; the 150K connected to the LM394 on Ken's site) for
tracking adjustment. This mod turned out to be a real time saver when it
came time to cal the circuit and may help Ken's VCO as well as far as
setup/calibration time is concerned. There's a bit more info about
"Magnus' mod" at my site:
http://www.charlielamm.com/synth/asmvco.php3
have built are good in this regard.
BTW, not sure if this helps, but, Magnus Danielson suggested to me, when I
was building ASM VCOs (very similar in their core design to what Ken has),
to put a 10K multiturn trimmer between the 150K resistor and V++ (R15 on
the ASM pages; the 150K connected to the LM394 on Ken's site) for
tracking adjustment. This mod turned out to be a real time saver when it
came time to cal the circuit and may help Ken's VCO as well as far as
setup/calibration time is concerned. There's a bit more info about
"Magnus' mod" at my site:
http://www.charlielamm.com/synth/asmvco.php3
On Mon, 16 May 2005, allanjhall wrote:
> I'm building the CGS48 VCO and also looking at the ASM-1 filter core
> on which it's based. Unlike many VCO's it doesn't have any HF tracking
> ajustment, so I'm wondering how well it tracks at higher frequencies?
> The design looks simple compared with some other VCO's; but this isn't
> necessarily a bad thing! I haven't heard any adverse comments on the
> ASM-1 filter's tracking ability so I'd guess it's fine, I'm just
> curious :-)
>
> Also, there is a revision (V1.1) to the ASM-1 VCO here:-
> http://home.swipnet.se/cfmd/synths/friends/stopp/asm1vco-1.1.pdf
>
> It seems to be the same as the original ASM-1 schematic except that it
> has an NPN transistor added between the output of LM311 (base) and the
> 18pf cap and 3k3 resistor (collector), the emitter goes to negative
> supply rail. Any idea why this mod was added to ASM-1? Something to do
> with sync perhaps? Just wondering if it would be beneficial to add it
> to my CGS48.....
>
> Allan
>
>
>
>
>
> See the following URLS for the CGS Modular Synth home page:
> Main: http://www.cgs.synth.net/
> Secondary: http://otherunicorn.0catch.com/synth/
> Yahoo! Groups Links
>
>
>
>
>
>