S-Transistors is targeting the scaling bottleneck in cryogenic quantum computers: power-hungry room-temperature electronics and separate bulky wiring for each qubit, which the company says superconducting transistors can replace with compact, low-power control hardware. Its EUR 2.6M pre-seed is funding product prototypes, a cryogenic laboratory, a manufacturing pilot line and team growth as it moves from wafer-scale technology toward a first multiplexer and the longer-term quantum motherboard.