WSG filter vero layout

[bikini-inspector]

hey folks!

i made a layout for the WSG filter as a standalone unit for use with my apc and the portasound keyboard.

i got it to work on the breadboard with the same components and found it nice enough to build it into a box.
Unfortunately the layout doesn't work, so after staring at it for hours trying to debug this bugger, i have to call out for help.

could someone please take the time and look over my layout?

rewards will be eternal gratitude and of course the corrected layout posted for free use by anyone


here's the schem http://www.electro-music.com/forum/phpbb-files/thumbs/t_wsg_filter_schem_2_167.jpg

later, ben

--------------------------------
EDIT:

nevermind, i got it working

i forgot C1, not sure what happened there....

also, all the pots are now NOT reversed .
Its possible and nice to have a 1M log pot in reverse for freq, though. In case you'd prefer only one freq knob. More fine-tunable that way...

anyways, have fun!

---

WSGfilter_vero.png
Description:	now verified, pots are viewed from top
Filesize:	89.91 KB
Viewed:	4067 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

[-minus-]

Good to hear it's working. The IC is a LM741 though. My WSG filter is still on breadboad. Had a few issues with hum but I seem to have got around it somewhat with additional components... but I can't remember what offhand !

I might try this layout of yours and see if I have better luck!

Thanks

[hoyager]

Is this how this filter is supposed to sound?





I'm just using the 1MB pot for freq and it seems to bunch up the control to the open end of the pot, but also doesn't go low enough to cut the audio...

I've used 560pf instead of 470's and C8 is only 100uf rather than 220uf and am running a dub step arcade siren through it.

Andy

[jordroid]

I think that is indeed how that filter sounds, your samples sound quite nice actually. I don't have my WSG anymore, but i think i remember the filter not completely cutting off the signal when turned down, maybe someone who has one could verify that? If the resolution seems all bunched up at one end you could try a log pot ( or would it be reverse log? i'm not sure. ) for the filter, it may help. Your capacitor substitutions i think will shift the range of the filter as well, if you have a stash of caps you could try series/paralleling them to try to get closer to the correct values.

It is just a super simple filter for a noise maker, but a nice sounding one, in a grungy kind of way.

regards,

jordan

[hoyager]

Thanks for the reply, I've tried 390pf's and 250uf for C8 with little change. Its funny that no thread about this filter, of which there are a lot, mentions the lack of a good sweep, from open to closed on the freq pot.

For anyone else who's interested the pot shafts are facing up in the layout. Freq knob should be filtering out highs when turned down, to the left.

Also by omitting the freq fine (100k pot) a much smaller value on the coarse should suffice, from about 500k down to 0k has little effect on mine.

Right on to this rene schmitz ms20 with the bipolar power

[bikini-inspector]

hey guys,

sorry i didn't look in here for so long!

minus, the 071 works fine in this filter. In my experience, most opamps are interchangeable, as long as you pay attention to the pinout and stuff like single/dual/quad...
also, this thing is dead quiet since i took it off the breadboard, no hum, but also no more oscillation...might add a feedback control for that..


hoyager, that's pretty much how my filter sounds. I think there might be a little more resonance in mine, though. Maybe because of the difference in cap values?
about the range: yeah, i guess that's why the original design has fine and coarse controls....doesn't matter to me that much, as i am mostly having it LDR controlled for now.

what i would suggest is using a log 1M pot for freq control wired in reverse, so that the filter is open when fully CCW. Or, if you have one, use a 1M revlog pot for the same effect. That way, the interesting parts of the freq are in the "shallow" areas of the pot taper, allowing better fine tuning.

It's true that it doesn't cut audio, im thinking of it more like a wah pedal with tunable reso.

soundsamples will come, as soon i got my recording setup ready.



anyone know of a better way to make this thing voltage controlled than using a LDR/LED combo? This thing needs to wobble!


anyway, i'm glad this has been of some use to some.feel free to keep me posted about future tinkering!


regards,
ben


EDIT
-----------------------------

ok, the sample's here, a bit long, but i got carried away, you know how it is....

test samples of stuff i built by shiz cake



also, i tried using a 500k pot, but then i fried it in another experiment, so now im back to 1M. Esp with the LDR, it allows for more bottom end, but not much.

[artifus]

been working on this myself so i thought i'd post my efforts here for others to make use of. still getting my head around diylc so they're a bit messy but you should be able to figure them out.

741 version is built and verified with the addition of led power indicator with current limiting resistor and a 3.5mm mono jack which interrupts the freq pot connection to the board to allow for a light dependant resistor to be connected which are not shown. also, i didn't have a 750k to hand for the input resistor so used 100k (all i had) on board with a 1m pot which lets you tweak response depending on the output level of the circuit driving it and an output level pot.

1458 version is not completely verified as yet but have one side running on breadboard. be sure to check it over before commencing a build referencing the scheme linked to above.

---

1458 dual odd filter.jpg
Description:
Filesize:	244.33 KB
Viewed:	1175 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

---

741 odd filter.jpg
Description:
Filesize:	173.14 KB
Viewed:	1798 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

---

[robman84]

Apologies for digging up this old topic, but in artifus' layout above, what does C5 do, joining +9v and - together? I'm a newbie, but managed to make a working Atari Punk Console and now want to add in an active filter (I've made a simple passive one). So before I destroy some components can I please ask:

* Will this circuit run straight off a 9V battery? I get confused by all the talk of bipolar power supplies.

* Could I power it from the same 9V battery that is powering my APC?

Many thanks

Rob

[artifus]

c5 acts as a little reservoir of power for the rest of the circuit to draw upon.
yes it will run from a nine volt battery and yes the same one as your apc.

http://fluxmonkey.com/electronoize/opampFilter.htm

[robman84]

Great, thanks. Parts ordered!

[Snaper]

[ZeroMax]

I assembled a slight variation on artifus' 741 "Odd" filter using components that are popular on eBay now (specifically,
style pots and sized strip board.)

Built and verified. (You can tell I have a favored supplier.) 1M "Alpha" pots may have to be ordered by the slow-boat, but for a single-supply resonant filter this is about as good as it gets. Black "cuts" are drill-outs for the stabilizers. (Use as small of a bit as possible if you need to do this.)

I don't suppose anyone's ever done a roll-off graph for this circuit...?

[csj2k]

I've just made this, using Bikini-inspector's layout at the top of the page and it works well. I added it on to a simple 555 piano circuit to make some much more interesting sounds.