JST Power Adapter

Overview

Each adapter feeds one Eurorack module from a 5-pin JST PH cable. The cable plugs into the top of the board. A female socket on the bottom pushes straight down onto the power header of the module. Use it with the m-power bus.

• The 16-pin board supplies +12V, −12V and +5V.
• The 10-pin board supplies +12V and −12V. It does not use pin 5 of the JST header.

JST pinout

This is the same pin map as the busboard slots, so connect cable pin n to pin n.

Rev A boards: the revision is on the bottom silkscreen. Rev A has pins 1 and 3 the other way round. Cross the wires on pins 1 and 3 at one end of the cable. With a straight cable, the diodes block both rails and nothing is damaged.

Protection

Each rail goes through a series Schottky diode, so a cable with swapped wires cannot push current backwards into the module. The diodes drop about 0.35 V, so the +5V output is about 4.6 V. The board has no fuses: the busboard has a fuse on each slot.

16-pin board: if you plug it in the wrong way round, no current flows. The supply GND does not reach the module GND, so no rail has a return path.

10-pin board: if you plug it in the wrong way round, +12V and −12V change places. The board has a notch in its edge and a silkscreen arrow at the −12V end. Line up the arrow with the red stripe and check it before you apply power.

Parts

Solder J2 on the bottom face. All other parts go on the top.