[TK.]

Since months I was thinking about a nice housing for my 4 CEM3378 filters and AOUT_LC modules. Finally I got the idea, that nothing would be easier than just to integrate the modules directly into a mixer. So, I opened my "Eurorack" linemixer from Behringer and was very happy to find enough room for all the boards:



As a nice side effect, the PSU is already there. It delivers +/- 15V. I'm using a 7905, 7805 and 7812 to regulate the voltages.

The AOUT_LC module is supplied with +12V/-5V (+12V to get enough headroom for the filter CV). Two modules are stocked for best utilisation of the available space in the mixer case:


And here the first audible results I got out of a MIDIbox FM / 4*CEM3378 combination:
http://www.midibox.o...MyBehringer.mp3
I especially like the bubbling sounds when the filters are in high resonance, and controlled by the LFOs and EG5 :)

Best Regards, Thorsten.

[stryd_one]

Holy crap that sounds nice :)
Great idea too, to put it in a mixer like that! I will remember that trick for my FX, and keep an eye out on ebay for cheap mixers :)

TK, do you know if the SSM2044 would be suitable for a similar application? I have a good cheap source of those IC's, but the CEM3378 are very hard to find....

[NorthernLightX]

Hi TK,

Why do you need -5V? Is it for the AOUT_LC or for the CEM filters?

Cheers,  Alex.

[TK.]

Yes, the SSM2044 should do the same, a sound comparison could be interesting.

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Why do you need -5V? Is it for the AOUT_LC or for the CEM filters?

It is for the CEM filters, and as the negative voltage is available, I'm also using it for the AOUT_LC module.

The CV inputs (of the *external* CEM3378 circuitry -> see datasheet) are working in a range of ca. 1V-7V (CutOff) and 0V-3V (Resonance). In addition to the gain/offset trimmpots of the AOUT_LC module, I'm using 10k trimmpots against ground at the filter CV input side - all 4 AOUT_LC modules deliver the same voltages when the CVs are swept from min to max, and with the additional 10k pots I'm able to fine-adjust the desired maximum resonance and I equalize the CutOff frequencies of all filters on an easier way, than with the non-linear gain/offset pots

Best Regards, Thorsten.

[stryd_one]

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Yes, the SSM2044 should do the same, a sound comparison could be interesting.

Thanks TK. I'll order in the next few days :)

[Artesia]

hmm thats some mighty fine squelchy ambience... reminiscent of the orb's - orbvs terravm

btw stryd, have any luck with the ssm2044's ?

[stryd_one]

Got a tube of them here, and known-good schematics (thanks to a kind donor ;) ) and I'll be breadboarding and setting them up for midibox control after some other projects are done.

[AndrewMartens]

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I'll be breadboarding and setting them up for midibox control after some other projects are done.

Heh, heh, heh... I know how that goes!