[sdiy] 10 octave VCO circuit from EDN June 4 2025

[Roman]

I think it will be good enough with plain BC857BS but the key here is low leakage diode that flips the mirror to expand usable tuning range at low end.
Maybe it's better to replace it with transistor.
Anyway IMHO the expo converter will spoil the tuning response more than any mismatches in this innovative VCO core. 

Roman 

Roman 

---- Użytkownik René Schmitz napisał ----

> On 07.06.2025 08:26, Paul Perry via Synth-diy wrote:
> > https://tinyurl.com/57fd674d
> >
> Hmm, interesting to see NTC for temperature compensation, and (buffered) 
> ARP style exponentiatior . Looks somewhat similar to my VCO4069.
> 
> That bidirectional current mirror is quite intriguing. I wonder how good 
> the symmetry it is, and how well the transistors have to be matched.
> 
> Cheers,
> 
> René
> 
> -- 
> 
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> http://schmitzbits.de
> 
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