professional manufactured SSM2044 VCF PCBs are AVAILABLE!!

Usine Karate · Joined: Jun 09, 2007 Posts: 64 Location: Hackney Wick

Hi Fink, don't suppose you have any pcb's left? I Would be interested in two, and if there are none left I would be interested in two in the future if you get any more made.

Usine Karate · Joined: Jun 09, 2007 Posts: 64 Location: Hackney Wick

Errr, sorry, I'm not sure if Fink is a rude wordbut it certainly looks it somehow, I actually meant Fonik, not Fink. Embarassed

prophei · Posted: Tue Jun 12, 2007 4:39 pm Post subject:

i got my ordered boards from fonik today, and the build quality is beautiful! such a change from the EFM boards I recently bought.

i can't wait to assemble these!

i hope he does another run of pcb's (nudge nudge), as i could see wanting more of them...

crashlander42 · Joined: Oct 21, 2006 Posts: 292 Location: Orlando, FL (US)

That board was the easiest thing I've ever built, and a great filter! If you do another run I'll buy another. If you do another resonators run I'm all for it as well! (hint hint)

bubblechamber · Posted: Wed Jun 13, 2007 11:18 pm Post subject:

I don't want to start a rush, but it looks like the cheaper chips on EBAY are running low. It looks like he's got 114 left...

fonik · Posted: Thu Jun 14, 2007 1:04 am Post subject:

hi all,

ERRATA:
1) some brainy fellows pointed out that the connectors are rotated by 180deg. thankyou for that.
if you take a look at the pic of etaoins populated PS3100 PCB (posted in the PS3100 thread: here) you will recognize, that he had to rotate the socket.
actually the footprint is rotated, the designation of +15V/GND/-15V is correct though. so follow this labeling no matter how the footprint looks like and you are fine.
it's just because i do not use the MOTM style connectors myself and for the ribbon connector it actually does not matter (on the doepfer bus the negative rail is placed at the end of the connector so i chosed that one to be pin 1 of the connector).

2) cap C10 has a wrong footprint. it should have been a polarized cap with the positive pin headed to R13.

3) for the Q CV i recommend a attenuator for this input has a linear response (honestly: how often do you use CV on resonance?).

Dave Kendall · Posted: Thu Jun 14, 2007 2:45 am Post subject:

fonik · Posted: Thu Jun 14, 2007 2:58 am Post subject:

prophei · Posted: Thu Jun 14, 2007 10:30 am Post subject:

hello all,

i just wanted to get on here and say how much i like this board (pcb). i assembled this easily, and am now working on adjusting it for how i like it... it sounds AMAZING.

the board quality is very good, the documentation is clear and easy to follow. i am very much a novice, but this worked the first time i turned it on. great job fonik! this is such a pleasure after spending weeks trying to make EFM designs even work at all. Rolling Eyes

-prophei

Mooger5 · Posted: Thu Jun 14, 2007 12:47 pm Post subject:

Fonik, C10 is in series so I think there´s no reason to worry about polarity. A non polarized cap will work just as well. The reason an electrolytic was chosen was because of the higher capacitance needed to let the signal pass without no high-pass filtering effect. So any polyester 2.2uF will also do the job, with higher fidelity. 4.7uF even better.

fonik · Posted: Thu Jun 14, 2007 12:58 pm Post subject:

Mooger5 · Posted: Thu Jun 14, 2007 1:02 pm Post subject:

That´s correct.

fonik · Posted: Tue Jun 19, 2007 7:00 am Post subject:

FYI
the footprints for the potentiometers are layed out in .800'' grid (same as doepfer).

in case you want to panelmount the PCB using the potentiometers keep in mind that there has to be enough space on the fronpanel to the right of the potentiometers (for the PCB).

prophei · Posted: Sun Jun 24, 2007 8:03 am Post subject:

hello all...

i have built this board, and was successful at getting everythiing to work great....EXCEPT.... i seem to be unable to get enough range out of my main cutoff pot.

i have played with all the trimmers, i have messed with changing some resistors up and down in value (mostly the r9, r11, r15)... and i still do not get enough range.

what i ended up doing was to bring out T2 as a normal single turn pot, which does allow me to get full range of cutoff when used in conjunction with the main cutoff pot... but this is a messy solution, as i should be able to get from the deepest lows to the highest highs all from my main cutoff pot.

i know that it is possible, as plenty of instruments i have used that utilize this chip do it just fine, and i would figure that you all would have commented on this if the pcb design was bad.... which i believe 100% it is not. any ideas?

i do want to mention that i am a but of a noob here, so i am plenty willing to accept i did something wrong, so ANY ideas you may have regarding what that error may be would be very helpful.

to be clear, everything else works.... just not this scaling.

thanks!

-prophei

p.s. just wanted to say that fonik has been very responsive to my emails regarding this... i just wanted to bring this in the open cause he seemed to kid around that i was some sort of coward for not doing so Wink

fonik · Posted: Sun Jun 24, 2007 2:11 pm Post subject:

hi prophei,

concerning scale:
this evening i hooked up one populated boarded again and guess what: i couldn't scale it to 1V/oct Shocked

. previous test must have been influenced by thus far unknown psycho acoustic phenomena Question

the only difference between these PCBs and the prototype inside my modular (which is definitely scaled to 1V/oct) is that the proto utilizes one quad OPA (i use TL084, not a good choice but that was the one i had on hand then) instead of two dual OPAs (tonight i tried both an TL072 and an TL062 for the scaling). i sold several home-brew PCBs using a quad and one fellow scaled his for 4 oct.

anyway, the scaling is actually done by the gain of the summing OPA for the control voltages. so i tried different values for R11 and ended up with 300k tonight, which is quite funny because the 270k are taken straight from the ssm2044's datasheet.

solution: replace R11 by a 300k resistor.
conclusion: it might be a good idea to replace T1 by an 100k trimmer and R11 by a 220k resistor. this should give us a wider trimming range.

concerning range of cutoff pot:
i'd tried to lower the value of R15. tell me if it works for you.

BTW are you powering your modul from 12V or 15V?

prophei · Posted: Sun Jun 24, 2007 2:59 pm Post subject:

thanks for the info! i guess i am not completely crazy then Laughing

i will try what you suggested and get back to you!

regarding 12 or 15v.... i started with 12v, but then realizing that this may be adding to the problem, i went up to 15v. which is this best suited for? 15v i assume...?

prophei · Posted: Sun Jun 24, 2007 5:11 pm Post subject:

i am still having trouble with the filter, even with the new values...

i have it set-up the best so far, at least to where i could almost use the T2 trimmer as my cutoff control instead of the intended P2. a bad work around, i know!

here are the values i have changed that are of note:

R15 - 22k
R9 - 220k
R11 - 303k

i have been chasing this issue back and forth, so it is entirely possible that these values could vary a little bit in their worth... but this combination has been the best so far.

oh... the comments/descriptions that go with the example attachments will make the most sense if you listen to the third first, then second, then first... they got a little out of order when i added them. Embarassed

one last thing to mention... i am running a saw wave into the filter, then running the audio out without the use of any cv inputs. just straight i/o.

trimmer_sweep.mp3

Description:

this is the best sweep i can get using the trimmer (T2) as my cutoff knob, with the cutoff knob (P2) adjusted (like a trimmer) to allow the trimmer (T2) to hit the peak resonance. notice that i still can't get a full range, as the low should get to a poin

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Filename:

trimmer_sweep.mp3

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330.03 KB

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969 Time(s)

cutoffsweep_trimlow.mp3

Description:

this is a sweep using the intended cutoff control (P2), and adjusting the trimmer (T2) to allow this sweep to start at the deepest point shown in the example where i used the trimmer to sweep the entire filter range. notice by how much i miss the resonant

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cutoffsweep_trimlow.mp3

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319.35 KB

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cuttoffsweep_trimhigh.mp3

Description:

here is the reverse of the cutoff (P2) sweep that started at the lowest point from the trimmer (T2) sweeping example. this uses the trimmer (T2) to adjust the cutoff (P2) so that it will hit the same resonant peak in my trimmer sweeping example. notice ho

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cuttoffsweep_trimhigh.mp3

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fonik · Posted: Sun Jun 24, 2007 11:03 pm Post subject:

mmhh.

i find the resonnance somehow irritating.

first i'd tried to listen to the filter fed by a static wave (triangle/saw) without any resonnance.

then i'd tried to listen to the filter without any audio input, selfresonnance only (a pure sin wave), trying to tune and scale it.

chonald · Posted: Sun Jun 24, 2007 11:08 pm Post subject:

Does anyone have Mouser part numbers for the PC Mount pots on this board?

fonik · Posted: Mon Jun 25, 2007 6:52 am Post subject:

prophei · Posted: Mon Jun 25, 2007 7:07 am Post subject:

prophei · Posted: Fri Jul 06, 2007 10:17 am Post subject:

endif · Joined: Jul 14, 2006 Posts: 138 Location: Reno, NV

Looks like you're out?
Bummer.
I wanted two.
=[

prophei · Posted: Tue Jul 10, 2007 8:14 pm Post subject:

i'd prolly take more as well, and know a few people who'd feel the same. Wink