Polivoks filter

[crashlander42]

I breadboarded the Polivoks filter tonight using the schematic form http://m.bareille.free.fr

I like it a lot. It reminds me of the MS20 filter clone with the input gain turned down, but when you turn the input gain up there's magic. It turns into a nasty evil distorted beast. It has that crazy squelchy resonance that the MS20 dies when it's turned to max. I'm definitely putting this together on veroboard tomorrow.

Here's a video of my trial run. I crank the gain about 1/3 of the way through and crank the resonance at the end.

http://www.youtube.com/watch?v=3ZypalMfkFI

I'm curious if anyone else has built this and if theirs sounds similar. I used the UA776 and UA741 in mine, if that makes any difference

[Funky40]

it sounds good your one.
I think better than my one. But i have unfortunately no input attenuation which is higly recommended.
Then it's also recommended to build with The UA776 ( i just know this, never got the LM4250. but everybody who has compared them says the same )

and i then would recommend to build it with a Outputmixer stage,
but this might be a thing of personal taste.
I use my Polivoks mostly in BP mode, but mix sometimes some LP to it.
But sometimes when jamming with a sound i twiddle around with the mixer.
so i have allways a mixer next to the Polivoks and the polivoks patched by default to it

shit, i shoulda make a friendship with the Breadbord too.
Nice setup you have !

check good the Range of the CV input pots if you have not.
they may need some adjustment. On my filter it is really bad.


edit:
my old thread:
http://www.electro-music.com/forum/topic-13248.html
the demo is made without any input attenuation.
the module on the left is akllways in use. THATS my polivoksfilter
the one on the right is in frac format, but i have no fracrac still today
I'm on the way to repanel them. i make a dual Polivoksfilter.
But i'm not shure if i should make a new panel as i have allready more Ideas.

[crashlander42]

I lucked out on the UA776's. My local surplus store had some. I used attenuators on my inputs, which makes a huge difference. It also amazes me the range of different tones you can get just from adjusting your input levels.


I like your layouts. The bandpass filter on this thing sounds awesome. I have plenty of mixers, so I didn't do an output mixer. I nearly gave it the same panel I did for the MS20 clone.

Here's my panel. I know it's a little jagged, but I cut it with a jigsaw. I need to get to a table saw to cut some more blank panels.

Here's a picture of the vectorboarded (stripboard, veroboard, whatever it's called) Polivoks as well. I was pretty pleased with my work.

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Description:	Here's my Polivoks panel. I know it's a little jagged, but I cut it with a jigsaw. I need to get to a table saw to cut some more blank panels.
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polivoks stripboard.jpg
Description:	Here's a picture of the vectorboarded (stripboard, veroboard, whatever it's called) Polivoks as well. I was pretty pleased with my work. :D
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[Funky40]

[endif]

I haven't finished my M.Bareile pcb, but I did buy the Harvestman clone.. naaasty. >=]

[haxster]

I recently have been fooing around with this design. Here is a schematic of the values i used and how i fixed the cutoff problem.

http://electro-music.com/forum/viewtopic.php?highlight=polivoks&t=23246

I have designed a new Pro PCB. I just need to make sure it is 100% error free. It is to arrive 2 week of December 2008. It is self powered, more like an external modular unit.

[davebr]

I just finished building a Polivoks filter also. I chose to wire it by hand and grabbed whatever perfboard I had in the drawer. Then I found this forum posting and found by coincidence we had built them on the same perfboard. I just thought that fact was interesting. I'm still waiting for my front panel to finish the module. I did a lot of comparisons between the NTE888M and TL071 op-amps and the 2N3904 transistor and the Russian УД1208 and KP140УД85 op-amps and the KT315Г transistor. I also implemented a few mods including 1V/octave tracking and changes to the self-oscillation waveform.

[EDIT - I got some uA776 parts and added a comparison of those as well as a couple of videos and sound samples to my Polivoks filter page.]

My Polivoks page is at http://modularsynthesis.com/kuzmin/polivoks/polivoks_vcf.htm

Dave