The transistorkreis random is a quad true random voltage generator for modular synthesizers and can be used for modulation and for digital noise. Each of its four outputs can be switched to uniform or normal random distribution, unipolar or bipolar voltage range and an amplitude of 5 Vpp or 10 Vpp. There are two inputs to trigger new random voltages, which can also process trigger signals with rates in the audio range. The generic design of the transistorkreis random supports any modular format and its firmware is open source. DIY kits for the Moog (MU) and the Eurorack format are available at Exploding Shed.