While the Phatty series has a rather incisive, modern character, the Grandmother focuses on pleasant, fat sounds with a classic flair. Audio signals are generated by two oscillators based on the Minimoog. In addition to controls for waveform selection and tuning, there is a hard-sync option. The VCOs are followed by a CP3-style mixer. Results are fed into a classic transistor ladder low-pass based on the Moog 904 module. Its slope is -24 dB per octave, the sound is huge. A cutoff frequency potentiometer allows you to sweep from 10 Hz to 20 kHz. The resonance goes up to whistling self-oscillation. In addition, a -6 dB high-pass was implemented. The filters are followed by a VCA based on the Moog 902 module. But that's not all! There's also a copy of the 905 spring reverb. Its sound is metallic and very gentle. If you slap Grandmother a little, you get rattling percussion effects.
On the modulators side of things you will find an ADSR envelope (Moog 911) with sustain fader and an LFO. The latter reaches into the audio range. In addition, two bipolar attenuators and a multiple with four connectors are available. For playing the Grandmother, you will find a 32-key Fatar keyboard with velocity. Additionally, there are pitch and mod wheels. There is also an arpeggiator and a sequencer. The latter can hold three patterns with up to 256 notes each.
Of course, even Grandmother cannot live without technological progress. There are MIDI DIN sockets and even USB-MIDI. For the connection of guitars, drum computers and the like, a 6.3 mm jack socket was installed.
As a semi-modular synthesizer, most components are hardwired. Thus, you can just hit the keys and enjoy. However, many of the normalizations can be broken using patch cables. A total of 41 modular sockets is available for sound experiments. In detail, 21 inputs and 16 outputs were built-in. Combining Grandmother with modular equipment is not a problem, of course.
21 patch inputs
16 patch outputs
Multiple with four connectors
6,3 mm jack input and output
MIDI DIN input, output and Thru connector