[sdiy] EFM VCO4

[Jay Schwichtenberg]

Tom,

I looked at my documentation for the VCO 4D and here is what I see. Some
EMFisems! First there are only 5 VC inputs into the 4D expo converter and 2
of those are for course and fine tuning. That leaves 3 available but there
are 4 on the panel. Looking at the panel in my documentation its for the 4E
which has 6 inputs vs the 4D's 5 inputs. You want at least 1 of the inputs
to be 1V/oct. for keyboard control. For controlling freq. modulation level
I'd put a pot on the input of at least one of the other inputs. For the
third I'd say it's your call. If you want to have an attenuated modulation
or not it's up to you.

Also note the FM control pot. The wiper should not be the input and the top
leg of the pot should not go to the op-amp. Top leg should be the input and
the wiper to the op-amp. If done the way the schematic is done turning the
FM pot all the way down will short the input into it. This could possibly
burn up the pot or the circuit driving it. Depends on the parts and circuit
design.

Jay

> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl
> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Tom Arnold
> Sent: Saturday, March 06, 2004 1:01 PM
> To: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] EFM VCO4
>
>
> Has anyone here build one of the EFM VCO4D's?
>
> I already asked this question on the EFM list and directly to Tom and have
> gotten a partial answer...  There are 4 CV INs on the front panel
> 2 labeled
> 1v/OCt and 2 labeled CV1 and CV2.  A quick guess about where all 4 should
> connect was confirmed by Tom, but I still havent found out where
> to hook up
> the two pots labeled CV1/CV2.  Anyone have a hint?  I'm sure Tom will get
> back to me with an answer, but I kinda wanted to finish these
> guys today and
> all thats left is wiring the front panel...
>
> Thanks!
>
> --
>  ------------------------------------------------------------------------
>  - Tom Arnold -       When I was small, I was in love,                  -
>  - Sysabend   -       In love with everything.                          -
>  - CareTaker  -       And now there's only you...                       -
>  --------------         -- Thomas Dolby, "Cloudburst At Shingle Street" -
>