Doepfer

> hi all!
> just curious about possibly anomalous behavior i've noticed... in
> addition to my A100 rig, i also have another separate keyboard
> setup that includes a "micro-modular" system based on a Dark
> Time/Energy combo expanded with 2 mini-cases of modules,
> including 2 A110 oscillators (more portable than the 5 G6 racks
> ^_^ ). I have the Time controlling the Energy over MIDI, with the
> CV1 output of the Energy controlling the 110s. the problem is the
> tuning on the 110s is offset from the tuning on the Energy: with
> the Energy's VCO tuning knob at 12 o'clock (which is in tune with
> MIDI, i.e. root key is "C"), the 2 110s have to have their tuning
> pots turned almost fully clockwise to be in unison tune with the
> Energy. this is a consistent offset even when i change control to
> all 3 running from the CV out of the Time instead of the MIDI
> control (Time->CV->Energy & 110s instead of
> Time->MIDI->Energy->CV->110s), though that adds the additional
> separate phenomenon that root pitch on the Time is also off: i.e.
> root "C" is when the Time's knobs are at approximately 12 o'clock
> instead of full counter-clockwise as when i use MIDI (again this
> is a completely separate issue from the 110 tuning offset
> phenomenon - this also makes MIDI key control into the Time
> offset as well, i.e. i hit a "C" on the MIDI keyboard and the
> Time outputs CV for a lower "F#" or so). note: when the 110s were
> part of the big A100 their tuning consistency was fine (12
> o'clock=unison), so it's not the 110's fault.
> maybe the CV out calibration on the Energy is a little off? and
> maybe the Time also?
> just curious if anyone else has noticed such behavior, or if it's
> isolated to my particular units.
> i hope i made all that as clear as possible :-) as i said it's a
> couple totally separate issues:
> 1) tuning offset between Energy & 110s
> 2) tuning offset difference between Time MIDI out vs. Time CV out)
> that then interact to create a compounded dysfunction. thanks in
> advance for any comments or advice.
> Be Seeing You!
> --chris

The problem is probably caused by the simple power supply used in the A-100
miniature cases. The standard power supplies of the "big" cases is adjusted
to exactly +/- 12.00V. The power supply built into the A-100 miniature cases
uses simple voltage regulators (7812, 7912) that cannot be adjusted and have
some tolerances (typ. +/- 11.5 ... 12.5V). As the absolute pitch of the
A-110 is affected by the supply voltage this is probably the reason why the
tuning of the A-110 is a bit off the Dark Energy. If you own an A-100
standard case (A-100G6, A-100P6/P9, A-100LC6/LC9 or any monster case) you
may try this out. I'd expect that the A-110 is in tune with the Dark Energy
when it's powered by one of these cases.

But there is a simple solution: adjust the trimming potentiometer P6 (VCO
offset) on the A-110 board so that the A-110 is in tune with the Dark Energy
VCO (i.e. with the manual frequency controls at the front panels of both
units in center position). Details on our website:

www.doepfer.com > PRODUCTS > A-100 > Module Overview > A-110 > service
manual

If you only touch P6 nothing can go wrong. But do not change the position of
any other trimming potentiometer.

Best wishes
Dieter Doepfer