[sdiy] High frequency VCO as BBD clock

[rrsounds]

Generally speaking, BBD devices have a limited number of “buckets." The faster you cycle through them, the shorter the delay. 500kHz is going to result in a pretty short delay. On the positive side, the S/N is also related to cycling rate, resulting in a much cleaner result at higher rates. 
Are BBDs even still produced?
David Reaves

> On Feb 7, 2023, at 19:18:08PM, 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

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