DB-120 Daughterboard for MOTM-120


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Last updated: September 7, 2009


The DB-120 is a daughterboard for the MOTM-120 Sub-Octave Multiplexer. The DB-120 adds individual outputs for the four sub-octaves, a staircase wave that is the binary weighted sum of the four sub-octaves, and a switch for selecting either AC or DC coupling for the staircase wave and the signal appearing at the MOTM-120 OUTPUT jack. The four sub-octave outputs are DC coupled square waves that swing between +5 volts and -5 volts.

Total current draw for DB-120 and MOTM-120 is 35 mA @+15V and 26 mA @-15V.

Circuit design by Richard Brewster.


As of September 7, 2009 this daughterboard is completely sold out. Sales have been very slow for this board over the past 4 years. I have no plans to make any more of these. Thanks to everyone who bought one.

MOTM-style front panels for this module can be ordered from The Bridechamber and Stooge Panels.


The User Guide does not contain detailed explanations on how to install parts or which kinds of solder to use. The intended audience is the experienced kit builder who is quite comfortable building a circuit from a description, a parts list, and a schematic.

DB-120 User Guide rev 1.0 (pdf)

DB-120 Schematics rev 1.0 (pdf)


DB-120_pcb_fs.jpg DB-120_pcb_bs.jpg
PCB Top View PCB Bottom View
DB-120_mothers.jpg DB-120_daughters.jpg
Motherboard Installed Daughterboard Installed
DB-120_connects.jpg DB-120_powers.jpg
Motherboard Connections Power Connection
Front View