Internally the A-108 is a 8-stage low pass filter with different slopes available: 6, 12, 18, 24, 30, 36, 42 and 48 dB per octave and in addition a band pass output.
By default the 4 low pass outputs of the A-108 are internally connected to the filter stages 6, 12, 24 and 48dB as there seemed to be the best output combination generating different sounds. E.g. the audible difference between the 48dB and 42dB or between 42dB and 36dB is very little.
But if desired any of the filter stages can be connected to one of the outputs by changing the internal connections (jumpers or wires). Each of the filter stages can be used but only four at a time. Even a multi-way switch could be used.
Resonance (Emphasis or Q ) can be adjusted manually right up to self-oscillation, in which case the filter will behave like a sine wave oscillator. The A-108 features an external feedback input that enables the insertion of additinal modules into the feedback path (e.g. VCA for voltage controlled resonance or phaser/frequency shifter for phase/frequency shifting effects). The socket is normalized and internally connected to the 48dB low pass output if no cable is inserted into the feedback socket.
one audio input
filter outputs: 6dB, 12dB, 24dB, 48dB, band pass
one resonance feedback input
three cutoff CV inputs: 1x with 1V/octave, 2x with attenautors
3U Eurorack module, 12HP wide, 75mm deep
power consumption 75mA