New module design: dual VCF

Grumble

I use two analog devices AD9833 for clock generation for the programmable universal switched capacitive filters MAX261.
The AD9833 must be the hardest part to solder in this build.

IMG_20160418_110853.jpg

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Remember: the perfboard holes are 0.1" apart...

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Grumble · Posted: Mon Apr 18, 2016 2:53 am Post subject:

The preliminary diagram, no values filled in and it will evolve while building.

schematics 2VCF.JPG

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LFLab · Posted: Wed Apr 20, 2016 11:03 am Post subject:

Dat is interessant! Hoe klinkt ie?

Pretty good! So how hard is it to solder that ic, a lot tighter than soic8?

Grumble · Posted: Wed Apr 20, 2016 12:05 pm Post subject:

How does it sound? Dunno, am soldering and designing the board.
I have already built a similar filter on my noise module and the soundfile of the noise module is here
The distance from center leg to the next is in the AD9833 0.5mm, while the SOIC has 1.27mm, so yes, soldering is quite tedious. Luckely I have an old stereo preparation microscope to do this kind of work.
I will build the filter on the board and than breadboarding the controls for testing purposes.
Each MAX261 has two filters on board, and the idea is to have the first used as a low pass filter and its output fed into the next and from the second filter section to use the low pass and band pass filter and make some kind of cross over and also add the original signal (the amplification of one section is -1x so two in series makes a 1x amplification, so in phase with the input exept near the center frequency of the filter).
So, I don't know how the end result will be schematics and sound wise...

soic.jpg

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This is about the same scale

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Grumble · Posted: Sat Apr 23, 2016 1:52 pm Post subject:

I have been programming the filter, and here are the first results.
Now the face plate and the wiring...

sqaure fast response.wav

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sqaure fast response.wav

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square sweep filter high q.wav

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square sweep filter high q.wav

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square sweep filter low q.wav

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square sweep filter low q.wav

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square sweep filter mid q.wav

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square sweep filter mid q.wav

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noise change q.wav

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noise change q.wav

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Grumble · Posted: Sat Apr 23, 2016 1:59 pm Post subject:

highQ.JPG

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This is what you get in: square, filter high Q

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Blue Hell · Posted: Sun Apr 24, 2016 12:46 pm Post subject:

Nice! I like your non-standard approach to design of musical circuits.

Grumble · Posted: Sun Apr 24, 2016 3:49 pm Post subject:

Thank you!

Cfish · Joined: Feb 24, 2016 Posts: 477 Location: Indiana

Very nice. And that's no easy soldering job even with a stereo microscope. I tried a little basic SMT once, finally took it to a customer of mine who did it roboticly. Was cool to see that, but I think your solder job looks just as good.

Grumble · Posted: Mon Apr 25, 2016 1:22 am Post subject: