Yahoo Groups archive

Doepfer

Index last updated: 2026-04-29 00:15 UTC

Message

AW: [Doepfer_a100] Re: A-111.5 tuning problem

2012-05-22 by yahoo@doepfer.de

> Hello Mark
>
> On 21.05.12 22:21 , mark wrote:
> > so I'll see what it does when it's back in my system
> Just a word about that: The tuning and octave tracking is depending on
> the powersupply voltages. You may adjust a VCO in a foreign system to
> about 99% of its abilities, but the last 1% is only reachable, if you
> adjust it connected to the powersupply with which it will work in the
> future.
>
> So I suggest, that you bring at least that rack to EMIS, where the VCO
> is attached to.
>
> Florian

I don't think that this applies to the A-111-5 because it has additional
internal voltage regulators for the CEM3394 available. The internal supplies
for the CEM3394 are +8V and -5V. Even all tuning controls for the VCO
(octave switches, tuning control at the front panel, internal offset
frequency trimming potentiometer) are connected to the internal +8V
and/or -5V. But for other VCOs it's correct - provided that not the
A-100PSU2 is used. The A-100PSU2 is adjusted in the factory to +/-12,00V
within +/-10mV so that the supply voltage tolerances should not affect the
VCOs. But for simple supplies (e.g. with 7812/7912 regulators only or for
switching power supplies) the supply voltages may affect the VCO tuning.

Best wishes
Dieter Doepfer

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.