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Duofonik dual SSM2044 board and euro adapter.
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3, 4, 5  Next [all]

Would you want a dual SSM2044 board?
yes, I have some SSM2044s sitting waiting for something!
 20%  [ 13 ]
ye,s but only if I could get tested non fake SSM2044s for it.
 53%  [ 33 ]
Yes, and Ill find the SSM2044s myself.
 16%  [ 10 ]
No, thank you.
 9%  [ 6 ]
Total Votes : 62

Author Duofonik dual SSM2044 board and euro adapter.
I have some of these left for people with SSMs, however the chips have become expensive and plagued with fakes/rejects, so when they are gone, that is all.

This design will be replicated with a dual core ladder filter using modern SMD transistors, stay tuned!

final board as sent off for run1/prototype

the difference between this and Fonik board:

Dual board

inverting input available on filters

has inputs to control both filters resonance and frequency at the same time

A, B and MIX outputs. inverting one input will get you a bndpass on the mix out.

divergence control. works great with mixer, powerful "through zero" modulation of bandwidth (not the control voltage going "through zero" but the bandwidth. it will go down till it is nothing then cross and start expanding again with inverted audio)

option to have master frequency control pot (controls both)

option to have master Q control pot (controls both)

a lot of features could be doubled up for 2 boards, for instance the master frequency and Q could go to both boards, the mixers could be shared as well, for a lot of cancellation/reinforcement shenanigans.

CGS style "sum" pads for DIY mods (frequency CV, Q CV and mix bus.)

MOTM or euro power.

size= 4.2" x 2.1"

First proto run is in production. the price difference for a lot more boards was silly, so I took the risk there wont be any massive errors. it a bet my boards will be good, vs waiting another 2 or 3 weeks turn around. if it pays off, then 50 boards!

If perfect or only in need of minor fix, it will be available (with any fixes done) around the end of Jan 2012 . I have a limited number of tested SSM2044s as well.
Junk Rhythm
How big is the PCB and is there an estimate on the price?
I still haven't built my Somatic board yet, but this looks great! Sounds flexible. Looks like it could be roughly 2.5 x 5ish? Just a rough estimate based on chip sizes.

I might be in for one of these, but I need to grab a couple more 2044s.

I like the power connector configuration. thumbs up
i definitely want a diy ssm2044 filter, but would need to secure good ssm2044 ics as part of the deal
The board is 2.1 x 4.25 which is (Correct me if i am wrong) short enough to fit euro/frac.

The price will depend on how many i order. somewhere from $15-25.

I would buy and test some SSM2044s but i can not work out the price yet. they vary quite a lot. (from $5 at UTsource) and up to ridiculous prices. I am hoping the UTsource ones are ok, Im ordering a few from them, for now.
Junk Rhythm
Neutron7 wrote:
The board is 2.1 x 4.25 which is (Correct me if i am wrong) short enough to fit euro/frac.

That will fit in Euro for sure. EDITED Just realized that you mentioned in another thread that you have a bunch.
4.25 should fit, my rule of thumb is 4.2 but it's awfully close either way. I'm interested but would need 2044s - even just a link to a source would satisfy me.
negativspace wrote:
4.25 should fit, my rule of thumb is 4.2 but it's awfully close either way. I'm interested but would need 2044s - even just a link to a source would satisfy me.

I'll try and shave off another 0.1" but it's pretty tight.
Well there was no room to make it smaller, but i moved the output connector so the wires wont stick out at the end of the board, and euro people will not have to squeeze wires past the mounting rails.

(see first post fol latest board)

to keep things easy, both "sides" have the same component numbers as Foniks schematic. with some additional components.

RA 47k for master Resonance CV
RB 100k for master Frequency CV
RC 100k for master Frequency Pot
RD 4.7k for negative input
RM is the extra 47k resistor for the "wider range" mod use a jumper if you don't want that.
CA 10u for negative input (oops, forgot to mark it, its next to c10)
all unmarked boxes are 100n(0.1) capacitors rather than 10n
H1 master bus header, so multiple boards can share the master controls.
The header will work with boards back to back or stacked the same way around)
choke beads are used instead of 22R resistors 1 and 2, but you can use resistors if you like.
I have another question, which i will ask here rather than starting a new poll

It would be desirable to mix the outputs because when you mix a low pass filter with an inverted version at a different frequency you can get a band pass, with different contours depending on the amount and res of each one.

If you could attenuvert the second filters CV input it would be nice as well. so you could modulate up or down the "difference" from the master CV.

It might also be nice to have a series/parallel switch and a couple of other things.

the question is, what option and why would you prefer it:

1: make a bigger board, nobody's going to put it in a panel that small anyways! (for low profile euro boats)
2: keep the board the same size and make a daughterboard (expensive and i might end up sitting on a lot of them)
3: make a "snappable" board where you can snap off the option part and discard or use it as a daughterboard (a bit more expensive, and cant be done on prototype boards)(kind of all or nothing)
4: don't bother and let people work out that stuff on stripboard or whatever. (keep the price low, and i can send it off soon, after checking my traces a few more times)

when i send them off i will get 10, if they work as expected, or only with a minor documentable and easy fix. i will be able to release 6-8 of those (with any fix that might be needed done)
If there is demand,I will get more(with fixes if needed)

RE: tested SSM2044s, it seems like a popular option after "i have some already"
I have ordered a small batch of SSM2044s, and will be working out a testing setup, using one of the boards and a ZIF socket, I will be able to "certify" them and maybe even do some matching, the better matched they are the better they will both follow the master controls together.

Well, being a MU person, I'm up for a bigger board of course!
Interesting though if you came up with a design that had the "snap-off" concept, but was sawable in the prototypes for those with less space.

Also it would have been fun to include a feature like the shruthi and have a hi pass, thought the band pass optio is interesting I've got a whoe stack of 2044s ( not that I've tested them!!!) so it would be good to get them to work.

I like the dual filter concept used in the Crumar Spirit a lot, though I'm biased in that this was my first synth too!

"The UPPER FILTER U and LOWER FILTER L section contains five rotary controls and three rocker switches. The FILTER UPPER is a variable resonance Low-Pass filter with either 12dB or 24dB cutoff, whilst the LOWER L is selectable as Parametric Boost or High-Pass. The MASTER rotary pot moves the cutoff frequency for both UPPER and LOWER filters, whilst the LOWER ONLY sets the relative frequency of FILTER L. The Cutoff point coincides if the LOWER ONLY control is set to 8. The UPPER FILTER may be selected as LOW resonance (0.5Q) or VARIABLE, set by the RESONANCE knob. The FILTER LOWER resonance is always set by the RESONANCE control. Both filters may track the keyboard at a rate set by KB AMOUNT, or FILTER L may be set as a static FORMANT filter. In the DYNAMIC setting FILTER L is modulated by the FILTER ENVELOPE as FILTER U. The filters also have an OVERDRIVE setting for extra fuzz!"

Anyway, don't want to de-rail the topic...!

Keep wiggling.

This one would be something for my system..

im in for one board and ssm2044 chip if its possible.
great design. i never got around to do another batch of mine, since i don't use expressPCB anymore and i would had to design a new one in eagle.
hey, if i had not two ssm2044 in my system already, i would buy two PCBs myself...
thumbs up

EDIT: thank you for doing this and asking me about it up-front. this is a great community...
I would take one.

I have 2 of Matthias boards waiting in the backlog but the master control and inputs to control both filters resonance and frequency at the same time is something that would be super nice.

I started working on the attenuverters and mixer parts, and decided it might as well go on a (compatible) separate board, because it would be a handy thing to have on its own.
Junk Rhythm
I have 4 extra SSM2044 if anyone needs them. They are from a group buy that are known to be legit. $10 shipped within the US. International, let's talk.

I would have posted this in the B/S/T Forum but I wanted to make sure the DIY guys get first shot at them. thumbs up
I just made a breadboard version, It works very well.I tested 14 SSM2044 and they were all good, just minor variation to the frequency as set, and how much the "self osc" trimmer had to be st to.

I have made a few changes since last time,
The board is a little smaller (4.2x2.1)

decoupling caps are now SMD or "solder to bottom pad" hopefully lots of people are used to this from CGS, JH, etc.

there is an onboard mixer which will mix the 2 filters output. when one is using the inverting input, that will give you a bandpass. (you can make pseudo high pass, if you set the higher filters frequency really high)
If neither or both filter is not inverted, then the output will be louder (if they are still running from the same source)
there are separate outs as well, of course.

the A side has a trimmer to null the outputs when the filters are cancelling each other. (could also be brought out as a control)

there is a "divergence" control on one of the frequency inputs one goes up while the other goes down, and vice versa. this iis quite cool with one filter inverted because they do a sort of "through zero" thing where the band opens back up with inverted audio after reaching and passing the equal value.

thesre are still "a+b" (both sides controlled at once) available for a Q CV. a f CV, and option for Master frequency pot instead of 2 separate ones.

Because i wanted to keep it small, I got rid of the "2 board" headers, but there are pads available if people really wanted to do that.

After i double and triple check this i will send off for a small quantity.
That looks excellent! Can't wait.
Oh man, i have three of these already! Very nice layout and especially feature set though!

Neutron, did you see my reply on the shield modulator?
Junk Rhythm
I'll take one PCB when they are finished.
I want 2 pcb´s.
Looks interesting!

Is there a complete feature set, or list of inputs, outputs and controls please?

Yeah, any idea of cost if you include the chips?

probably up for a board and the 2 chips.
Isaiah wrote:
Looks interesting!

Is there a complete feature set, or list of inputs, outputs and controls please?


There are 2 SSM2044 filters based (with permission) on foniks design. with some additions to enhance the fact there are 2 filters.

they could be used as:
2 independant filters.
"stereo" filters with small variations in the left and right channels giving some stereo depth.
Combination of the filters to give different filter modes.

these are options, you can use or not use whatever you want on your panel
depending on weather you want to do everything possible, or make a small panel.

In A +
In A -
In b +
In b -
usually you would just use one for each side, and use a pot or switch to change polarity.
CV res A
CV res B
CV res A+B (controls both at the same time)
CV freq A x2
CV freq B x2
CV freq A+B
CV freq divergence


Freq A
Freq B
Freq A+B + difference.
res A
res B
res A+B
null (option to bring out trimmer)
attenuators for CV inputs.
Yes, I'd be up for at least one if not more depending on the cost.
I have a drawer full of 2044s so would be good to put them into service!

Keep wiggling,
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