[sdiy] More about the Aries VCO

[JH.]

Now that I know the internals of the expo onverter, I've taken a closer look
at
the whole thing.

This CA3080 based schmitt trigger is very clever! Must be pretty fast *and*
precisely bouding at fixed level without saturating.
(Does anybody know at what current it is working, i.e. the value of the
resistor at pin 5 of U4 ?)

I still wonder if it is *that* fast (and if the transitors have such low
rbb) such that
it doesn't need any HF tracking compensation ?!

JH.


----- Original Message ----- 
From: "JH." <jhaible at debitel.net>
To: "phillip m gallo" <philgallo at attglobal.net>; "sdiy"
<synth-diy at dropmix.xs4all.nl>
Sent: Sunday, June 13, 2004 11:15 PM
Subject: Re: [sdiy] Aries modulars


> > The potted expo converter was hidden under blue "blot".  This "blot"
when
> > held to the light did allow you to just make out the Q81 and three
> > transistors.  I penciled the components in and went on my happy way.
> >
> > After all these years the pencil is about all that is left as the
> remaining
> > drawing is  quite faded.
>
> 8-)
>
>
> > A year ago i started to revise the DWG on the net to include the expo
and
> to
> > correct any differences between the blue schematic and the net
schematic.
> > Never finished but the schematic of the expo was:
> >
> > http://www.geocities.com/phillipmgallo/ariesexpo.gif
> >
> > As can be seen, it's what i call a standard "Boston" expo used by
> > ARP/CFR/DYNASYN/ARIES/ELECTRO-SCIENCEMART.
>
>
> Thanks for sharing this - yes it all makes sense now!
> (I had expected something more complicated, but sure, this is it!)
>
> JH.
>
>