Befaco - i² Instrument Interface (B-Stock)

The i² Instrument Interface has to be considered a practical tool for extracting voltages from an injected audio signal, e.g. to generate dynamic modulations by various control voltages and to generate triggers and gates. The module has a pre-amp and a band pass filter as well.

B-Stock unit with signs of usage. Power cable, screws and washers are included. Comes without original packaging.

The module consists of a number of circuits: first of all there's a pre-amplifier with big and small input jacks and a gain potemtiometer for setting the amplification. The pre-amp is followed by a band pass flter with adjustable center frequency and width for eliminating unwanted signal portions, like bassdrums which, due to their high energy mask other frequencies' level and cut a lot of dynamics from the envelope follower.

The pre-amplified and filtered signal is available at the audio out but is being sent simultneously to the other function blocks:

• Envelope Follower follows the audio signal's amplitude changes- Three selectable velocity responses.
• Envelope Regenerator: generates an Attack-Decay envelope from the audio signal; with adjustable time parameters.
• Trigger Extractor: A comparator that produces a gate and a trigger when the audio signal exceeds a threshold. The gate remains high until the audio level drops below the threshold again.