Doepfer A-100(~ 40 MB) - Manual (Page 620)

A-185 Bus Access System A - 100 doepfer
4
5. User examples
Creating a common system bus for an
A-100 with more than one 6U rack system
If your System A-100 fits into just one 6U rack, and you
want to connect up the upper and lower system bus-
ses so that their CV and gate signals are linked, you
can usually just connect them internally with the optio-
nal A-100BC cable (see the A-100 main system ma-
nual, chapter 3, page 10).
But if you want to connect the CV and gate signals on
two or more 6U racks, then module A-185 comes
into its own.
Fig. 2 (see next page) shows the basic connection
plan.
A
Important note concerning the A-190:
If, as in fig.1, you connect up the signals from an
A-190 MIDI interface to the system bus via an
A-185, you must disconnect the A-190’s
internal connection from the system bus
(see the A-190 manual, p. 4).
Compensation for signal losses
There are also times when an A-185 is useful even
with just one 6U rack. Particularly if you’re running
more than two VCOs from the same common sy-
stem bus, the internal CV voltage can drop sufficiently
for the keyboard scaling to go slightly out, causing high
notes to be annoyingly out of tune. The booster ampli-
fier if the A-185 will avoid any such problems.
Losses of the gate voltage normally cause no pro-
blems as low threshold values (~2...3 V) are required
to trigger gate inputs (e.g. ADSR A-140). However for
pitch control voltages even a few millivolts will cause
an audible detuning.
When feeding external pitch CVs to the A-100 (e.g.
from an external MIDI-to-CV interface or from one our
sequencers MAQ16/3, Schaltwerk or Regelwerk) the
usage of an A-185 is recommended - especially if
more than one VCO is driven by the external CV.
Even for voltage losses of other pitch processing
modules (e.g. the slew limiters A-170 or A-171) the
A-185 may help in case of detuning problems.