MOTM 440

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

BOM:

M440_bom.pdf

Builders Guide:

MOTM440 User's Guide.pdf

Parts:

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

• pots:

• 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 diysynth.de (my shop)
  4x SSM2210 → i have drop-in replacements on diysynth.de (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)

http://www.muffwiggler.com/forum/viewtopic.php?p=1175840&sid=f286a3c98a3a58e25cbd2bf90200d1cd

further a other issue was found on one pcb:

http://www.sequencer.de/synthesizer/viewtopic.php?t=87264

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 !

tip