A DIY "no-MIDI" guitar controller for 1V/Octave synths

[Macaba]

For anti-aliasing purposes, yes. You want a low pass filter that rolls off at half the sampling frequency. In the real world, you would roll off earlier, to ensure the high frequencies are attenuated sufficently.

Good observation!

[stefano]

[bugbrand]

I reckon I'm going to make one up shortly too --- Stefano, that's the PCB straight from the project document, right?

All the parts look pretty standard which is good -- reckon I'd use an SSM2210 instead of CA3046 though..

[v-un-v]

[stefano]

[bugbrand]

[v-un-v]

[v-un-v]

Found it. Though it may be a bit pixelated

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[Wild Zebra]

[bugbrand]

Hey Stefano - I got my one working today ---->> after a while though..!..


There's one big error in the project that could cause confusion - in the parts list, IC11 is listed as a 4011 but in the schematic its shown and listed as a 4001 -- !!! --- changing over from a 4011 to a 4001 got things working.


So, its working and tracking a bit, but at the moment its really very unstable - if you try re-triggering notes they'll often repitch themselves. The tuning ain't good at the moment.. HoHum. Maybe I'll try to get a ca3046 'cos I'm currently using an SSM2210 (with suitable cludges)


Anyways, just wondered if you'd identified that problem before...

[v-un-v]

[StephenGiles]

Mmmm, no fundamental extractor, I can't see much possibilty of good stable tracking!

[bugbrand]

[StephenGiles]

Both.

[Fernando]

Here is a V/oct to V/Hz converter that works:
http://rubidium.dyndns.org/~magnus/synths/schematics/
scroll downt to "V/oct to Hz/V converter" or
http://rubidium.dyndns.org/~magnus/synths/schematics/oct2hz.pdf

[stefano]

Yeah, it was the eighth message of this post (see previous page of this post, it was a message of mine). Anyway there are other errors (E), the article must have been written in a hurry ! For instance:
E1) - there is listed in the schema of fig.2, for IC7 a CA4046 instead of the proper CA3040 (correct)
E2) - IC2,IC5,IC9 in fig. 2 are CA3140, but in the part list (correct) IC2,IC9,IC10 are CA3140
E3) - spare terminals of pots VR3 and VR5, according to the schematic should be connected respectively to pads 'F' and 'B' (though, I wonder if this is relevant)

Bye

[bugbrand]

Yeah,,,, I really oughta learn to read through everything (..guess teachers were right..)


Question on the MS20 design ---

VR6 -> looks like it needs to be a triple pot ? do such things exist? never heard of them....

[fonik]

[blue hell]

[Fernando]

oops, sorry, you are right we need the inverse conversion =:s

The MS20 was a very interesting interface

[Wild Zebra]

[StephenGiles]

The EH Guitar Synthesiser included a decent fundamental extractor which produced a sine wave from any input. As a result it tracked single notes from an electric guitar perfectly. Unfortunately it used 2 x CA3094, but they are still available at Smallbear.

[Fernando]

Harry Bissell told me that the Shin-Ei Octave's input section was great to condition a guitar signal for fundamental extraction.

This comment was around the PV1, a pitch to voltage converter by Harry based on a design by Bob Moog/Big Briar Etherwave Pitch to Voltage Converter. The PCB was sold by EFM some years ago (2000) as "PV1"
I'd like to post the schematic but I should ask Harry permission first, I guess...

Shin-Ei schematic

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[StephenGiles]

http://img.photobucket.com/albums/v317/StephenGiles/EH_sine.gif

[Fernando]

yummy