VCF tracking: no Tempcos?

[Jaba]

Hello,
I want to build some of the Yusynth filters (actually all of them), but now I notice that none of your those filters has tempcos; do they manage to track correctly when oscillating ? how is it ?
should I want to add tempcos, would you please give details about them, such as specific value, where to put it in the schematic, ... ?
thank you
Paolo

[yusynth]

Nearly no VCF (Moog, ArP, EMS...) have tempcos in them.

[Jaba]

thank you for your answer, but this sounds new to me

I am no expert, but all the schematics I have from ARP VCFs (4012, 4023, 4034, 4035, 4072, 4075) use a 1K87 3% 3500ppm Tempco resistor, and most transistor ladder based filters I have seen use a 1K Tempco 3000ppm, even the EFM VCF2f had it

maybe you just don't care about temperature compensation, or you found another way to make the tracking good enough, ... ?

but my point is: if I build your filters (trans. ladder and ARP4072) and make them oscillate, will I be able to play them in tune over at least three octaves ? (as if they were VCOs)

and if the answer is yes, then I would like to learn how you achieved it, if you would share your design criteria

[yusynth]

[Jaba]

great!
thank you a lot, this makes me very happy
No more excuses now, I'll have to build them all.

I'll order the kits from Bridechamber for diode ladderVCF, MiniMoog VCF and ARP4072 VCF, and buy 3096 and other components for a Steiner VCF

Any plan to do more ARP clones, such as the 4023 and 4034/4035 filters, or the Odysseys VCOs ?

thank you
PaoloV

[yusynth]

Hi

Have fun then

I have no plan of making more ARP clones, I am really satisfied with the ARP4072 and my yusynth VCOs, I am not interested in making ARP VCOs.
But one must never say "never"

[numbertalk]

[Jaba]

yes, very interesting
thank you numbertalk, and thank you yusynth

btw, which circuit did you build, numbertalk ? is it the dual ODY osc/ringmod ? it is already on my "to do" list

[numbertalk]