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
- Pcb, Panel, Bracket, pots, SSM Chips from bridechamber.com thx to Scott
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:
1x 1k Tempco 3300ppm on top of u14
- SEMIS and others
2x 1n4148 diode
1x TL1013 (MXL1013)
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 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 !