Doepfer

You find my answers written inline

Best wishes
Dieter Doepfer


> thanks for the reply
>
> i've removed jumpers so it acts as 4 separate vca's with no
> normaling and no summing...
>
> i did some tests
> this is what i get
>
> -run 5.47 v into vca1 input
> -run 3.85 v into vca1 cv2 input
> - i get   0.61 v out of vca1 output
>
> the same thing done with the other 3 vca's give's me 1.31v ,
> 1.37v , and 1.34v respectively ....
>
> i guess vca1 cv2 has a dud resister or something?

maybe. But to find out if this is true please check what I mentioned in my
last answer: CV2 of VCA1 should behave like CV1 with the trimming
potentiometer for CV1 in it's max. position (i.e. no attenuation). If the
CV1 and CV2 behave different it a problem with the VCA. Otherwise it's a
problem with the weighting resistor for CV2.

> sending this back (only a few months old) is probably not an
> option because i'm in Australia and i purchased from
> analoguehaven with some other stuff.... elby didnt have stock at
> the time... i was impatient..
>
> maybe an easy fix for me?
>
> is there a resister that i can check maybe?
>
> thanks

Please look if the resistors R8 and R9 are 220k (color code red-red-yellow
for 5% or red-red-black-orange for 1% types). These are located just behind
the trimming potentiometer for unit #1. These are the weighting resistors
for CV1 and CV2 of VCA #1.

If this is true I'd expect that CV1 and CV2 will behave in the same way
(provided that the trimming potentiometer is fully open). Please check then
if R11 is 100k. It defines the overall amplification of the VCA. R11 is the
next but one resistor behind R9. I can send you a silk screen overlay off
list if this helps.