Doepfer

Dear, my Doepfer a1434 VCLFO cycles between -5 volts and +5 volts, 
would it be possible to have it cycling between 0 volts and +5volts? 
Or between 0 volts and +10 volts? 
Should I try the "offset" and "scale" trimpots on the pcb? 

http://www.doepfer.de/A100_pictures/doepfer_a143_4.jpg 

http://www.doepfer.de/a1434.htm

Thanks!
Floris

Scale and offset is for the 1V/Oct control response, you don't want to touch those.  

I don't see jumpers on the boards for DC offset or rectifying, so you would need to modify.....or stick an offset/attenuator module on each of the outputs that require one.  

http://www.doepfer.de/a1832.htm

> On Mar 14, 2018, at 7:25 PM, 'Floris V.' florisvanhoof@ecomail.org [Doepfer_a100] <Doepfer_a100@yahoogroups.com> wrote:
> 
> Dear, my Doepfer a1434 VCLFO cycles between -5 volts and +5 volts, 
> would it be possible to have it cycling between 0 volts and +5volts? 
> Or between 0 volts and +10 volts? 
> Should I try the "offset" and "scale" trimpots on the pcb? 
> 
> http://www.doepfer.de/A100_pictures/doepfer_a143_4.jpg 
> 
> http://www.doepfer.de/a1434.htm
> 
> Thanks!
> Floris
>

> Dear, my Doepfer a1434 VCLFO cycles between -5 volts and +5 volts,
> would it be possible to have it cycling between 0 volts and +5volts?
> Or between 0 volts and +10 volts?
> Should I try the "offset" and "scale" trimpots on the pcb?
>
> http://www.doepfer.de/A100_pictures/doepfer_a143_4.jpg
>
> http://www.doepfer.de/a1434.htm
>
> Thanks!
> Floris

It's not possible to shift the output voltage range of the A-143-4 to
0...+10V. For this an external module (e.g. A-183-2) is required. Do not
change the offset and scale trimming as this will affect only the frequency
scale and frequency offset.

Best wishes
Dieter Doepfer

> as 4 offset generators would be too big and expensive for this
> project, would it be possible to modify one Doepfer A-138c
> polarizing mixer so I can offset each of the 4 outputs of the
> Quad VCLFO individually?
> http://www.doepfer.de/a138c.htm

I'm sorry - it's not possible to modify the A-138c in an easy way to work as
an offset generator.

Best wishes
Dieter Doepfer

> it will only be used with 4 Velleman K8064 DC controlled dimmers
> Maybe it's easier to modify the dimmer ciruits
> https://www.velleman.eu/downloads/0/illustrated/illustrated_assemb
> ly_manual_k8064.pdf
>
>
> All the best
> Floris

If you are familiar with electronics that's possible (adding a positive
voltage via another 4k7 resistor to the junction of R16 and D4).
But as the dimmers include parts, terminals and pcb tracks that are
connected to mains voltage I'd strictly disadvise against this modification
! Otherwise there is danger to life and you may damage the A-143-4 or even
more.

Best wishes
Dieter Doepfer

> One more idea would involve the "direction inputs" on the a1434 VCLFO
>
> Would it be possible to make it so that when the VCLFO is on 0v
> he resets and changes direction automatically and always stays above 0v?

This would require four external comparators (e.g. A-167) and is more effort
than the usage of the offset generators A-183-2.

Best wishes
Dieter Doepfer