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V/Oct to Hz/V converters?

Posted: Thu Sep 24, 2009 4:42 am
by Mooger5
To control a Yamaha CS with the MC-202 seq. Any commercial or DIY solutions? Searched using other keywords such as exponential to linear as well, to no avail.

Re: V/Oct to Hz/V converters?

Posted: Thu Sep 24, 2009 8:41 am
by pflosi
my roommate and i were trying (well he was trying that is) to build this:

Image

no success... but it should work in theory. i guess sth is f**k up here, maybe the testboard we were building it on...

for ms20 + tb303 / acidlab bassline 2

Re: V/Oct to Hz/V converters?

Posted: Thu Sep 24, 2009 8:48 am
by pflosi
ah yeah, and the only unit ever available that i know of is the korg ms 02... there are some sequencers and midi-cv converters that can do hz/v, but i dont think any of them would convert it from v/oct

Re: V/Oct to Hz/V converters?

Posted: Thu Sep 24, 2009 4:25 pm
by BoxPhenom
There's this : http://www.kentonuk.com/kenton/pcb_proj ... cvhzm.html

Most of the work is done but it requires a little DIY.

Re: V/Oct to Hz/V converters?

Posted: Thu Sep 24, 2009 6:28 pm
by nathanscribe
BoxPhenom wrote:There's this : http://www.kentonuk.com/kenton/pcb_proj ... cvhzm.html

Most of the work is done but it requires a little DIY.
I'd forgotten about those. I fitted one to a Pro-2 and it was a doddle.

Re: V/Oct to Hz/V converters?

Posted: Fri Sep 25, 2009 5:19 pm
by Mooger5
Thanks for the suggestions.
The Kenton would fit neatly inside a CS30...
Now that I know what to look for, the DIY route seems tempting.
Pflosi I´ve been researching a bit. That schematic is a part of the ASM-1 and looks like it was taken from the MS-02 Antilog Amp, although adapted for 15V. From what I can tell there´s a diode missing. Compare both.

Re: V/Oct to Hz/V converters?

Posted: Fri Sep 25, 2009 6:53 pm
by Mooger5
pflosi wrote: for ms20 + tb303 / acidlab bassline 2
BTW, did you use the trigger converter (v-trig to s-trig)?
And in this page http://www.geocities.com/SunsetStrip/Pi ... inout.html it says the ms20 can be patched to accept v/oct. There´s something similar at the Doepfer site.

Re: V/Oct to Hz/V converters?

Posted: Sat Sep 26, 2009 3:59 pm
by pflosi
the ms 20 can actually convert v-trigger to s-trigger (through the ESP), though it's only a trigger and no gate (no sustain) but that's alright for sequencing. yes, we also built one just to see if it was difficult - no problem at all.

and yes, both the ms20 and the ms10 can accept v/oct - the cv in for the osc (that can be adjusted, not the one that deactivates the keyboard) is exponential. but, that requires a lot of tuning and scaling. works fine in the studio, but no way doing that in live situations, so i tried to build the converter (in fact my roommate tried). by the way, motu volta works just fine with that input!

i'll check out the second schematic you posted, thanks. i think we couldnt do it because we used another transistor than the one mentioned in the schematic...

Re: V/Oct to Hz/V converters?

Posted: Sat Sep 26, 2009 11:20 pm
by DeFex
what a bout a pitch to MIDI converter http://www.synthdiy.com/show/?id=2373
and then a midi to voltage converter which is more common. and you could control other synths with the pitch to midi and use the midi to voltage converter if you wanted to control the synth from a different sequencer.

Re: V/Oct to Hz/V converters?

Posted: Sun Sep 27, 2009 12:42 am
by Mooger5
DeFex wrote:what a bout a pitch to MIDI converter http://www.synthdiy.com/show/?id=2373
and then a midi to voltage converter which is more common. and you could control other synths with the pitch to midi and use the midi to voltage converter if you wanted to control the synth from a different sequencer.
Interesting idea, just not for the set-up I´m planning :) I use one of the MC-202 sequence channels for the built-in synth and the other to send out cv/gate to the external synth. Both sequences/channels are independent, so the MC will play, say, the bass part while the ext. will play the leadline.
With this set-up I want to strictly use CV, but I´ll eventually get a MIDImplant for Hz/V.

Re: V/Oct to Hz/V converters?

Posted: Sun Sep 27, 2009 12:46 am
by pflosi
the ms20 has about the nicest pitch to voltage converter around :) and that is hz/v. you can actually take a softsynth with sine to control it, for example. looking at it this way, i have to say that the ms20 has midi built in ;)

Re: V/Oct to Hz/V converters?

Posted: Sun Sep 27, 2009 1:09 am
by Mooger5
pflosi wrote:the ms 20 can actually convert v-trigger to s-trigger (through the ESP), though it's only a trigger and no gate (no sustain) but that's alright for sequencing. yes, we also built one just to see if it was difficult - no problem at all.

and yes, both the ms20 and the ms10 can accept v/oct - the cv in for the osc (that can be adjusted, not the one that deactivates the keyboard) is exponential. but, that requires a lot of tuning and scaling. works fine in the studio, but no way doing that in live situations, so i tried to build the converter (in fact my roommate tried). by the way, motu volta works just fine with that input!

i'll check out the second schematic you posted, thanks. i think we couldnt do it because we used another transistor than the one mentioned in the schematic...
I see. Live situations are an entirely different game.
I´m not interested in the Volta. IDK why, maybe it´s too modern :lol:
What integrated transistor pair did you try? From what I have read elsewhere the LM394 is typical in these applications. Maybe it could be a direct replacement, and is easier to source than the MAT01. The author of the schematic you provided says you can substitute with a couple of commonly available 2N3904. But you´ll have to find a pair that matches.
I didn´t search the components used in the Korg, yet. Still looking for alternatives.

Re: V/Oct to Hz/V converters?

Posted: Thu Jan 05, 2017 1:30 am
by Jabberwalky
Curious if any ended up building that circuit successfully. So 2x 2n3904 would work?

I'm trying to mod my maxikorg with CV/GATE and it works on Hz/V, so I figured I could just build this board x2 and put it inside the maxi.

Any thoughts or stories about this?

Re: V/Oct to Hz/V converters?

Posted: Thu Jan 05, 2017 3:35 pm
by Mooger5
I never got the CS30 so I lost interest in building this. But it´s a common part found on any V/Oct VCO. Pretty much all VCOs are linear at the core so they all need a converter if exponential control is required.

But I had a look at the 800DV schematics and it works on +20V/-10V. I´ve never dealt with asymmetrical power supplies before...

2x 2n3904 would work, but they´d have to be matched for better linear response. A CA3046 would be a better bet. It´s five matched NPNs in one package. A single chip would probably be enough for processing Upper and Lower individually or both athe same time. Better ask Adamstan for advice.

The circuits posted above are for modular duties; they expect several CV sources at the same time and one even has two linear mod inputs. Parts of those sections could be eliminated off the circuit, simplifying the schematic.

Re: V/Oct to Hz/V converters?

Posted: Thu Jan 12, 2017 2:00 am
by Jabberwalky
Thanks for the incite Mooger! The assymetrical power supply is strange. I guess in 1975 there were very few rules. I'll see what I can do.