The expander contains a second sawtooth-core VCO identical to the one of the Synchrodyne, but with a different periphery and some differences in the patch points. There are individual outputs for sawtooth, triangle and pulse, CV inputs for linear and exponential Fm, a 1V/oct input, a PWM CV-Input and a sync input. The VCO has a second frequency multiplication circuitry (PLL) - it is identical with the one in the Synchrodyne but has much more patch points.
In the upper left of the expander you can control the clock of Synchrodyne´s switched capacitor filter. The clock source can be the first PLL, the second PLL (or the PMW of 2nd VCO) or an external clock which is fed into the circuit at the Clk3 socket.
The Synchrodyne´s filter is expanded by a vactrol based compressor that gets it´s audio signal either from the 2-pole output, the 4-pole output or from the side chain input (Comp SC In).
A second switched-capacitor filter is also available in the expander. It´s a 24dB low pass filter with a resonance that is shifted 180° in phase. Of course it can self-oscillate. The clock needed for operation can be origin from an external clock input but usually it is normalized to the PLL2´s output. The filter has two outputs: a normal -24dB one and an amplified diode-rectified output that gets it´s sound from the resonance feedback circuit.
Furtermore there is a number of additional in- and outputs like a wavefolder out, a filter input a VCA output and some outputs for the first filter.
a lot! ... see pictures
3U Eurorack module, 22HP wide, 45mm deep.
Current consumption is 90mA @ +12V and 80mA @ -12Vl
Total for both modules is 150mA @ +12V and 130mA @ -12V