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Projecttitel: MOTM 440


Startdate: 10.10.2014

Duedate: 01.12.2014

update 08-2020

Manufacture link:

Here's my latest Build from 2020:

MOTM440 in MU Format. let me know when you want one...


copy from old synthtech page:

You have probably heard of the SSM2040 filter chip, used in the Prophet 5 Rev. 2 synth, the Voyetra 8, and others. Although short-lived, the SSM2040 filter had a unique sound different from a Moog, ARP or other 4-pole lowpass. Why? The design used a clever discrete OTA gain cell.

The MOTM-440 offers an updated SSM2040 architecture using matched NPN/PNP pairs and features a switch that adds a second audio feedback path to boost bass response at higher Q levels. This makes the filter "growl and rumble" even more! In addition, voltage-controlled Q allows for more sweeping effects. Three audio inputs and three CV inputs make the MOTM-440 the killer lowpass filter in your system. The internal gain structure is such that over-driving the filter is now possible (unlike the Prophet 5) to get even more nasty sounds. Did we mention it self-oscillates at high Q?

So order a MOTM-440 filter for a fraction of the price of a P5 Rev. 2, but without the worry of obsolete parts!

"The MOTM-440 is the best-sounding analog filter I have ever heard." - Robert Rich



Builders Guide:

MOTM440 User's Guide.pdf


  • Pcb, Panel, Bracket, pots, SSM Chips  from  thx to Scott

  • pots:
        1ea 100K cermet Spectrol 149 VR1  (from Scott)
         3ea 100K conductive plastic log Spectrol 148 VR2, VR3, VR4  (mouser)
         3ea 100K conductive plastic Bourns 95A1 VR5, VR6, VR7  (mouser)
  • capaciators:
    4x 1nF polysterene or polypropylene  - banzai
    3x 3m3  bipolar electrolyt  - mouser, TME
    1x 1nF Filmcap
    4x 100nF MLCC caps
  • resistors:  only nontypical values here listed:
    3x 51k1
    2x 200k
    2x 20k
    1x 221k
    1x 3k6
    1x 44k2
    1x 1k Tempco 3300ppm  on top of u14
  • SEMIS and others
    13x bc550c
    2x 1n4148 diode
    1x TL1013  (MXL1013)
    3x TL072
    5x SSM2220 → i have drop-in replacements on (my shop)
    4x SSM2210 → i have drop-in replacements on (my shop)
    1x CA3086
  • Others:
    1x SPDT (ON-ON) switch
    8x Switchcraft 112A Jacks
    7x knobs Alco PKES90B1/4
    1x 20k bourns trimpot
    around 1-2m RG174 cable
    lot of cable for wiring the switches, pots
    2x ferrite beads
    1x MTA header

(not happen with pcbs from 2019/2020 from synthcube)

If you have purchased an MOTM-440 PCB that has a "P80316" silk screened in the upper left hand corner by the Synth Tech label, please run a wire descriped in picture (the pcb trace is defective)

further a other issue was found on one pcb:

if your Input 1 and your Frequenzmodulation dont work,  fix this by run wires:

Picture of missing traces here too: (fixed by above solution)

on my pics are the Polysterene values 1n5 instead of 1n,  1v/oct, CV RES, CV FM1, CVFm2 jack polarisation is wrong .

Pin1 and 2  is for the CV Jacks not with the same polarisation !