Here's also a quick text run-down of all the input and output functionality:
BD In: Input to the bass drum resonator. Note that, for normal bass drum behaviour, this circuit expects either a trigger signal or a decaying envelope. This is why
Decay 1 is normalled to this input.
BD Out: Audio output of the bass drum resonator.
Ring Mix: This is an audio input which allows for signals to be mixed in with the "ring" generator (6 XOR'd square waves). The
Noise Output is normalled to this input in order to give the hi-hat section more hiss. The level of this mixed input is controllable with the
Ring Mix pot.
Ring Out: Audio output of the ring generators +
Ring Mix signal.
TT1/2 Trig: Trigger input for the Twin T resonator. Note that a gate signal can be input here - there is a gate to trigger converter before each Twin T resonator.
TT1/2 Out: Audio output of the Twin T resonators, taken before the
TT Drive controls - these are used in the Snare Drum mix circuitry.
SD Mix: This is an audio input which allows for signals to be summed to the two (overdriven) Twin T resonators.
VCA 2's Output is normalled to this to form the noise section of the snare drum. The level of this mixed input is controllable with the
SD Mix pot.
HH In: This is an audio input which feeds the hi-hat filtering and VCA circuitry. The
Ring Output is normalled to this input.
HH Out: Audio output of the hi-hat circuit.
HH Envelope: Unbuffered output of the hi-hat envelope (both closed and open signals) which can be used to control external equipment.
OH Envelope: Like the above, an unbuffered output of only the open hi-hat envelope.
Decay 1/2 Trig: Trigger/gate input for the Decay envelope generators.
Decay 1/2 Out: Output of the Decay envelope generators. Note that the output of these are normalled to the corresponding VCA CV inputs, as well as Decay 1 firing the Bass Drum resonator.
Noise Out: Audio output of the noise generator. This is normalled to the input of
VCA 2.
VCA 1/2 Input: Audio input of the VCAs. Note that the
Ring Out and
Noise Out are normalled to VCA 1 and 2 respectively.
VCA 1/2 CV: Control inputs to the VCAs. The outputs of the two Decay envelopes are normalled to VCA 1 and 2 respectively.
VCA 1/2 Output: Audio output of the VCAs.
Mix Out: Audio output of the four-channel mixer, post Baxandall tone circuit.
Mixer Input 1-4: Audio inputs to the four-channel mixer and Baxandall tone circuit.
Hope this explains a bunch!
