Voltage controlled pan?

Pehr · Posted: Sat Oct 15, 2005 11:51 am Post subject: Voltage controlled pan?

Does anyone know if there exists any mixer with voltage controlled pan? I got the idea yesterday, but I don't know hold to build. It would be cool to control the pan of a sound with an envelope generator or an a LFO... Any ideas?

elektro80 · Posted: Sat Oct 15, 2005 2:09 pm Post subject:

There used to be many DIY VCA modules, designed for stereo or even 4 channels, around.. but it seems that the schematics / DIY kit biz is down at the moment.

Anyways, think stereo.. and at least double everything. CV controlled panning is not something new, but I guess it is still not quite accepted as being kosher. You know.. doing pans inside the synth.. UNCOOL! Laughing

We did touch upon this subject at least briefly in this thread:
http://electro-music.com/forum/topic-8105.html

Hmm.. or maybe we didn´t.. at least I mentioned it in there somewhere. I have always been a big fan of thinking spatiality when setting up patches.

mosc · Posted: Sat Oct 15, 2005 2:11 pm Post subject:

I found this one: http://www.solorb.com/elect/panner/index.html

elektro80 · Posted: Sat Oct 15, 2005 2:15 pm Post subject:

There was used to be some envelope/VCA module schematics around.. I think it was a 24 page leaflet. at least the 4 first ones were marked Bell Labs. I am trying to remember some details. I bought 2 of the PCBs from the UK.. but that wasn´t from Phonosonic though. Hmm..

elektro80 · Posted: Sat Oct 15, 2005 2:20 pm Post subject:

I think the leaflet was called "Think Stereo " and was put together by a german dude who had been involved with some fairly well known magazine DIY project. The ones that were sold in Norway had a greenish cover. There must have been more than 24 pages.. more 48 I guess. A4 format. I built 3 of the modules in there.

Jan? You seen this one? 1978-1980

blue hell · Posted: Sat Oct 15, 2005 2:29 pm Post subject:

me ?

Have no clue what you are talking about, seems like nice papers though what you mention.

I was going to suggest making a circuit using three VCA's, one to invert the control signal, one controlled by that inverted control signal and the last one controlled by the uninverted control signal.

But then I remembered that no analog synth will have thre VCA's, let alone have a proper DC coupled four quadrant VCA, so this is pretty useless I guess. Apart from that almost no analog synth will have fixed DC control signals available to make the lacking proper VCA do the invert trick.

It's so much more convenient to have this Clavia thingy laying around :-)

Howard's link seems the best thing sofar.

mosc · Posted: Sat Oct 15, 2005 2:31 pm Post subject:

A panner is simply two VCAs with the control voltage of one of them being the invertion of the other. That's eactly what that schmatic I posted does.

blue hell · Posted: Sat Oct 15, 2005 2:34 pm Post subject:

Was I suggsting otherwise ?

elektro80 · Posted: Sat Oct 15, 2005 2:42 pm Post subject:

Jan.. that is why those old schematics were very cool.

Those DIY modules left with the Roland 100 modules. I am pretty sure the leaflet went with that gear too.. just in case something needed repairs or something. But this HAS to be on the web somewhere anyway. Even scans of the Formant articles are available on the web now.

Sure, the pan circuit Howard found will do the job just fine, but it is more to this than simply panning stuff.. anyways.. ignore me. I still think the mono layout of everything from analog modulars to prerouted stuff like the Mini was a huge mistake. A tragedy. And then much later varius companies solved the stereo bit by adding a stereo chorus strapped on the synth output. Shocked

elektro80 · Posted: Sat Oct 15, 2005 2:43 pm Post subject:

elektro80 · Posted: Sat Oct 15, 2005 2:50 pm Post subject:

Pehr, ignore that link I posted. Whenever someone mentions CV controlled panning I will start thinking spatiality and stereo too. You want simple panning.. go for Howard´s post.

blue hell · Posted: Sat Oct 15, 2005 2:53 pm Post subject:

Still no clue :-)

Audio rate panning is fun to do though (and chorusing almost never is fun to use, exceprt maybe when set very very slow).

elektro80 · Posted: Sat Oct 15, 2005 3:35 pm Post subject:

http://www.synthesizers.com/q111.html

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

mosc · Posted: Sat Oct 15, 2005 4:59 pm Post subject:

Pehr · Posted: Sun Oct 16, 2005 2:32 am Post subject:

Wow!

for all replies. What I'm thinking about is a mono-in stereo-out panning mixer just like http://www.musicfromouterspace.com/analogsynth/stereomixer.html but with a CV-input for the pan... but the idea with two VCAs controlled by two LFOs out of phase is not a bad idea...

Rob · Posted: Mon Oct 17, 2005 7:31 am Post subject:

deknow · Posted: Mon Oct 17, 2005 10:11 am Post subject:

there is a dunlop stereo trem pedal (a big purple thing) that works quite well with 3 knobs:
lfo shape (square to sine)
lfo ammount
lfo speed

not as flexible as a vc panner, but for lfo use it works great.

deknow

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Pehr · Posted: Thu May 18, 2006 8:45 am Post subject:

Yay!

Ray heard my thoughts Rolling Eyes

http://www.musicfromouterspace.com/analogsynth/STEREOPANNER/STEREOPANNER.html

zipzap · Posted: Fri May 19, 2006 8:29 am Post subject:

The Pan/Fade module posted above looks good to me! Since i´ve gaot a quatratur osc now i need some VC crossfader!
This must basically concist of two vcas and a 2 in one mixer. OK, it´s easy to think of how to connect the ins and outs for either mode, but how can you go from one to the other with just one swich?

richardc64 · Posted: Thu Jun 01, 2006 8:51 am Post subject:

Greetings. I've been lurking for some time and this topic moved me to join in.

More years ago than I want to admit, I built a multi-function VCA using only one 3080. It could pan, cross-fade or be used as an ordinary VCA. It worked by putting 2 signals on the inverting and non-inverting inputs of the 3080 and then attenuating one signal or the other as CV rises by subtracting at the outputs. Maybe the schematic will make this clearer.
http://www.sdiy.org/richardc64/mmvca/

The breadboard version worked well enough that I built a Veroboard version. It never made it into my Synth, though. Something distracted me. (I know! It was the Commodore Vic-20 and C64. And then the damn Internet came along. Having to move a couple of times didn't help, either.)

I don't remember the trimming procedure for this circuit or if the control voltage had to be positive-going or +/-. No doubt it can be improved in a few ways. Something for someone to play with

I've recently "rediscovered" my old designs and have been scanning or, in the case of the panning VCA, redrawing them, so they don't get "lost" again.

Here is a bad webcam image of a bad Polaroid of some of the stuff I built.
http://www.sdiy.org/richardc64/proj/mysynths.jpg

You guys have made me want to build things again.

(edit:replaced dead geocities urls)

dnny · Posted: Thu Jun 01, 2006 9:08 am Post subject:

richardc64

Scott Stites · Posted: Thu Jun 01, 2006 9:57 am Post subject:

That circuit is just too cool for words. Thanks for sharing it!

Cheers,
Scott