Geosynchronous Synths GS1-U

The GS1-U builds on the GS1-NR utility module and provides three functions. The first is a ring/cross modulator function using the same LM1496 balanced modulator/demodulator IC as found in the Roland System 100M circuits. The second provides a transistor noise generator which can output both white and pink noise. The third is a gate delay circuit with configurable settings.

The module ring modulation circuit allows for metallic, crunchy cross modulation of two audio signals and has no further user control, besides the calibration trimmers on the rear to setup for optimal modulation (minimum signal bleed) however these can of course be used to offset the amount of each signal for those wanting to experiment.

The noise circuit uses the fabled 2SC828R NPN transistor. I say fabled because Roland created their urban myth regarding this transistor and the lack of a certain batch making them stop production of the TR-808. In reality, with empirical testing by Paul over at dinsync.info, when creating the RE-808 replica, almost any NPN can be used to generate the 808 noise! For example a 945P, or even a modern 2N3904 (although requires some leg twiddling) can be used!

The gate delay is taken from the Roland System 100M utility module. The incoming gate signal can be ignored up to a certain voltage, using the threshold setting. Once the module is acting on the gate, the length of the output gate can be configured. Finally the actual delay time is configurable to provide the actual gate delay itself. Not very sexy but overall this utility module packs a lot of features into a single 8hp module.