Oberheim SEM clone

build in 2025

pcb set is bought from synththomas

BOM:

SEM:

For the MASTER

For the MASTER SUB BOARD

SEM

please note: 2N5172 must be flipped 180 degrees against the Silkscreen

Internal Wiring

Wiring:

3pole MTA on left side (rear view)

left pin = Z trigger in

middle pin = Y = Gate

3pole MTA on right side

W GATE in

X Trigger in

Build notes:

15uF on the sub board is original value, different speed is available as mod with 0.15uF

0.15uF = 150nF is correct

BOM notes: 50KC with center detent is correct instead of the 20kb mouser link

the rotary are from banzai

PCb Scan v4