Synthesis Technology MOTM-120 Mods

1. Increase Output Level

Changed R10 from 33K to 200K to get 10 Vpp output from any one of the sub octave outputs. As designed, the only way to achieve 10 Vpp output is to have the two IN level knobs and all of the SUB level knobs set to 10. With this mod, the two inputs and each of the sub octaves will output 10 Vpp when their associated output level knob is set to 10.

Note that this mod multiplies each of the 5 Vpp outputs from the logic circuitry by two to get 10 Vpp levels. This doubling of amplitude also applies to the A IN and B IN signals. If the MIX A switch is set to NORM and a 10 Vpp signal is applied to the A input, the output level will be 20 Vpp when the A IN knob is set to 10. The same holds true for the B input. A voltage divider can be constructed directly across the input jack but I haven't bothered to do this; I can just turn down the A IN and B IN levels to compensate.

I undid this mod after adding the DB-120 daughterboard; it is superfluous with the daughterboard.

2. Add DB-120 Daughterboard

Information regarding the DB-120 daughterboard can be found here.