[sdiy] Aries 317 VCO

[Harry Bissell]

"U8" is an epoxy potted module, internally its an NPN/PNP expo converter with an additional transistor slaved off the
main expo for the sawtooth. There is an internal tempco potted in as well. I have a pretty fair idea what it probably looks like
inside, but you should study ARP expo converters of the same age. Dennis Colin was an ex-ARP employee and designed some of their
modules before joining Aries.


----- Original Message -----
From: Oren Leavitt <obl64 at ix.netcom.com>
To: synth-diy at dropmix.xs4all.nl
Sent: Wed, 30 Mar 2011 03:15:38 -0400 (EDT)
Subject: Re: [sdiy] Aries 317 VCO



On 3/30/2011 2:01 AM, lanterma at ece.gatech.edu wrote:
> On Mar 30, 2011, at 2:58 AM, Donald Tillman wrote:
>
>> It has the advantages of a triangle core (better tuning because there's no retrace, and you don't have to derive the triangle waveform from a sawtooth) and at the same time he doesn't have to derive a sawtooth from a triangle and deal with a glitch at the zero crossing.
>
> Interesting! Has anyone tried building it?
>
> - Aaron

I wonder what "U8" the expo converter is? The pin usage does not ring a 
bell...

The tri-sine converter is exactly the same as one that appeared in Barry 
Klein's "Electronic Music Circuits" book.
I have used that tri-sine converter - it works nicely.

- Oren
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-- 
Harry Bissell & Nora Abdullah 4eva