Doepfer A-101-1 Vactrol Steiner Filter - Manual (Page 4)

A-101-1 Vactrol Multitype Filter System A - 100 doepfer
4
Resonance can be increased up to self-oscillation . But
due to the vactrol tolerances and tracking errors mentio-
ned above resonance resp. self-oscillation deviations
over the frequency range may occur.
6 LP (control) / & LP In (socket)
7 BP (control) / / BP In (socket)
8 HP (control) / ( HP In (socket)
These are the audio inputs of the module with the
corresponding level controls (attenuators) for low pass
(LP), band pass (BP) and high pass (HP) function. Here
the audio signal resp. audio signals are fed in.
The audio input sockets are normalled, i.e. the BP input
is connected to the LP input provided that no cable is
plugged into the BP socket. Same applies for the HP ->
BP inputs. This simplifies the patch in case that a
common signal is used for the three filter inputs. The
arrow symbols at the front panel indicate the normalled
sockets.
The audio inputs are very sensitive to obtain distorted
sounds if desired. From about middle position ( ~ 5)
distortion appears with A-100 standard audio signals
(e.g. VCO output).
The level controls are adjusted to obtain the desired filter
sound.
The following table shows some examples for certain
control settings in case that a common audio signal is
used for all three filter inputs (i.e. the normalling feature
is used and the common signal is fed into the LP socket
and consequently available at the BP and HP input too).
The value "~ 5" is only an example. Instead of 5 any
other position (e.g. 3 or 8) can be chosen. But for
combinations that include multiple "~ 5" settings (e.g.
notch) all "~ 5" controls have to be turned to the same
position. Beyond ~ 5 distortion may occur that affects the
result too.
Control
LP BP HP Result
~ 5 0 0 low pass
0 ~ 5 0 band pass
0 0 ~ 5 high pass
~ 5 ~ 5 ~ 5 notch (inverse BP)
~ 5 0 ~ 5 band pass with offset
~ 5 ~ 5 0 low pass + band pass
0 ~ 5 ~ 5 highpass gate