A-127 VC Resonance Filter
Module A-127 is a triple
resonance filter unit. It contains three
separate voltage controlled band pass filters. Each filter has
it's own LFO (triangle waveform) with LED display and adjustable
frequency and amplitude. Instead of the internal LFO an external
control voltage may be used to control the filter frequency. In
this case the external voltage is fed into the external CV jack
(with integrated switch to turn off the LFO signal) and the
amplitude control of the LFO affects the level of the external CV
signal. Each filter is equipped with the following controls: LFO
frequency, LFO/external CV amplitude, filter frequency, filter
resonance and filter amplitude. In addition to the mix output for
all three filters each filter has a separate audio output. The
original audio signal can be added to the triple filter mix
signal with a separate control. All of the 3 filters share a
common audio input with attenuator. The filter audio inputs are
very sensitive so that distortion may intentionally be used to
create new sounds - if desired.
The frequency control range of the bandpass filters is about
40Hz...6kHz, the frequency range of the LFO's is about
0.02Hz...20Hz (= 1 min ... 1/20 sec per cycle).
Each of the three filters can used also as a 12dB low pass (with
resonance control) instead of band pass. For this a jumper has to
be changed on the filter board in question. In this case the
module can be called no longer "resonance filter" but
"triple low pass filter". It is also possible to modify
only one or two of the filters to low pass.
The A-127 is a versatile module for sound modification.
Width: 28TE, /Current: about 100mA