[sdiy] High frequency VCO as BBD clock

[Guy McCusker]

Mark is right of course -- there are some serious bits of weirdness in
the WAD schematic.

It turns out that the way the sample and hold is done after the BBD
taps means that one of the two taps in the first half never makes it
to the output. So the "short" delay tap is 1/4 of the "long" and not
1/2 as claimed in the Serge marketing literature.

On Fri, Feb 10, 2023 at 10:09 AM mark verbos via Synth-diy
<synth-diy at synth-diy.org> wrote:
>
> Kinda off the subject, but I find it really hard to believe the way the taps are coming off of those BBDs. The long looks ok, but….
>
> Mark
>
>
>
>
> On Feb 9, 2023, at 8:13 PM, S Ridley via Synth-diy <synth-diy at synth-diy.org> wrote:
>
> The Serge WAD (Wilson Analog Delay) might be worth a look - high frequency VCO driving two SAD1024s.
>
> https://www.elby-designs.com/webtek/cgs/serge/cgs208/cgs208_schematic.gif
>
> Spec says delays down to 0.5mS, dunno how well it tracks.  HF VCO is expo converter driving a CMOS oscillator.
>
> Steve
>
>
>
> On Tue, 7 Feb 2023 at 18:21, Rutger Vlek via Synth-diy <synth-diy at synth-diy.org> wrote:
>>
>> Dear list,
>>
>> For a while I've been working on a guitar pedal board for personal use. I'm about to build the second revision of a solid state pre-amp, and was thinking about possible modulation effects too. I would love a nice (stereo) BBD flanger/chorus, but felt a bit fed-up with all the 'classic' designs, particularly the traditional clocking scheme, usually with a limited range, lack of current drive (to overcome capacitance of the BBD clock input) and strictly linear modulation (calling for a hyper-triangle modulation source).
>>
>> Having some experience with designing saw- and tri-core VCO's around the 2164, I was wondering how easy it would be to push the design of a typical tri-core VCO with an 2164-based expo converter into higher frequencies (let's say up to 500kHz) and use it to clock a BBD? Has anyone tried? Or are there fundamental reasons why such frequencies are not possible? I've never (intentionally) worked with circuits outside of the audio bandwidth...
>>
>> Rutger
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org