Polivox VCF layout

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

The (quite popular) Polivoks filter, based on the schematic by M. Bareille. Uses programmable opamp ICs (uA776, NTE888, LM4250) and runs off +/-12V or +/-15V (not tested with lower voltages yet).

MOST RECENT VERSION:
http://www.2shared.com/file/pw5qsaqe/polivoks_updated.html

Old versions:
http://www.2shared.com/file/8sijvxp1/polivoks-vcf.html
(for information only)

Untested as of 12 Aug 2011. Feel free to try it out if you dare. Cheers Smile

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

Fixed, I think. Now it's a bit smaller and has caps on the power rails (only 100uF electrolytics, though, didn't have room to shunt them with some 100nF ones or so). Little, if any, is left of the original abuse of curve tool, now replaced with abuse of diagonal traces. The component layout looks kinda prettier, it's fun making those:

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Posted Image, might have been reduced in size. Click Image to view fullscreen.

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

Thank you!!!
I will try it in a near future!!!

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

Note that there's too little clearance around the three square pads - I'll make some room (perhaps move the pot a little) and fix that, too, but until I do, take care not to short them Smile

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

OK, thank you!

haxster · Posted: Fri May 27, 2011 3:58 pm Post subject:

If you add a 50k or 100k trimmer with the outer pins going to + and - and the middle pin to a 100k resistor and add that little circuit to the Main CV Line (where all the CV's mix or meet) you will make it work universal for all Voltage Power Formats. It will act as a Cutoff Range Offset.

It is worth the extra redesigning.

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

That's exactly the kind of feedback I need Smile

This will definitely go into the next revision.

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

Finally:
http://www.2shared.com/file/pw5qsaqe/polivoks_updated.html
Rolling Eyes

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

Thank you.

Did you tested this version?

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

Nope, but a guy at another forum already volunteered, and I myself got the ICs today, so it might be verified soon.

tokyomatik · Posted: Wed Aug 10, 2011 3:50 am Post subject:

it looks pretty easy
any news? is it working? somebody tested?....

egasimus · Joined: Feb 11, 2011 Posts: 113 Location: Bulgaria

No :/ The guy who tried to build it only got so far, but I haven't heard from him for a while. I think he had some problems with the power supply - he's a guitar stompbox guy, just like me. I'm hopefully gonna build my own bipolar PSU soon, though, so I'll eventually get around to testing it. Sorry :/

n.d · Joined: Dec 15, 2011 Posts: 52 Location: Talos IV

Hi there. Any news? Sebo? Anyone?

tokyomatik · Posted: Mon Jan 30, 2012 6:33 am Post subject:

I start to think that the only solution is trying to etch a board and see if it work.....

-minus- · Joined: Oct 26, 2008 Posts: 787 Audio files: 13

Can someone actually upload an image without having to go through all the hassle of links to other sites and zip files please?

2Shared The Easiest Way To Share Files... clearly is NOT the easiest. I can't get the file to download at all. Laughing

n.d · Joined: Dec 15, 2011 Posts: 52 Location: Talos IV

Yeah, took me two hours to DL.
Here it is.

polivoks_updated.zip

Description:

Download (listen)

Filename:

polivoks_updated.zip

Filesize:

143.08 KB

Downloaded:

1047 Time(s)

n.d · Joined: Dec 15, 2011 Posts: 52 Location: Talos IV

Please report back if you build it.
And egasimus, do you have the eagle - or kicad, altium, whatever- files?

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

I had the PCB etched for a while, but didn't had the time to solder anything yet...

tokyomatik · Posted: Thu Feb 09, 2012 11:51 am Post subject:

any news about this board??

tokyomatik · Posted: Thu Mar 08, 2012 7:14 am Post subject:

....so???? Crying or Very sad

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

I didn't do any advance Sad

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

Hi:
I just finished my Polivoks VCF using this PCB and I can confirm it works.
I just did some mods to improve the cutoff range and the CV inputs sensitivity, but this mods are the same all people do to the Marc Bareille version.
Thanks again to egasimus for share!!!

LFLab · Posted: Mon Jun 04, 2012 3:05 am Post subject:

I've etched a board for this thing, but haven't found time to assemble it into a module (and since I want it to be a dual, will need to etch another board).

What mods did you do to improve cutoff range and CV input sensitivity? Will need to see if I can change the layout slightly to incorporate the changes. Would also be nice to have a euro style power connector, since I have them on the bussboards in my cabinets, that's an easy enough addition.

Edit:
Did you tie the cutoff to V- with a resistor? That's also a mod for the SSM2044 VCF, helps tremendously.

Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

To imporve cutoff range I wired the side of the cutoff pot that goes to ground to -15V instead. Also changed R8 to 270K and put a 50K trimpot in series to finetune (I think I ended with a total resistance of 290K aprox).
To improve the CV sensitivity I changed R5 and R9 to 150K.

mrkva · Posted: Wed Jan 30, 2013 10:09 am Post subject:

How would one adjust this shematic for +/- 12V? Thank you