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Analog CV(control voltage) standards?
Old 22nd February 2014
  #1
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Analog CV(control voltage) standards?

Hi,

does anybody know if there are any standards when it comes to control voltages (VC)?

1Volt/Octave seems to be some standard, although I read that some synths (eg Roland SH-1000/2000 are workiing with 1.2V/Oct).

On the Doepfer site I read that their interfaces go from 0 to 5V. Is this some kind of a standard? Somewhere else I read that control voltages go from -5V to 0V.
Old 22nd February 2014
  #2
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The most common CV standard these days is 5V as used by Doepfer, most eurorack modules, current Moog gear and lots of others. On a lot of vintage synths it was 10V.

With a 5V standard you can have ranges like -5V to 0V, or -2.5V to +2.5V (still a difference of 5V), or 0 to 5V, etc.

The v/oct is another standard also used most manufacturers today for pitch scaling. The Korg MS-20 is the only currently available synth I can think of that uses a different standard, namely Hz/v.
Old 22nd February 2014
  #3
for most stuff in 3U world (euro and blacet frac), 5U (MOTM, com/moog) :

standard for pitch control: 1V/Octave

standard for parameter control: 0 - 5V

standard for bipolar modulation sources like LFO: +/-5V *

standard for gates and triggers: it depends. most are 5V, some 8V, some new stuff like makenoise work with 10V.




*sometimes you can use things like a envelope or a VCS that are loopable, that output 10V, and bring them via offset to +/-5V lke classic LFO.
Old 22nd February 2014
  #4
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@clusterchord -- Do you know offhand which standards MosLab uses?

(Their new website keeps crashing my browser for some odd reason so I can't check myself)
Old 22nd February 2014
  #5
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And if I have an old Moog Prodigy that was modfied with CV by somebody? What voltage would you use? I have no information about the mod.
Old 22nd February 2014
  #6
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The important thing will really be which mod they did for the gate signal. If they did the v-trig mod, 0v will be off and 5v will be on. If they did the s-trig mod(typical on old Moogs), it will be 5v off and 0v on. The reverse, basically. Is the jack labelled? That may tell you. If not, you may just have to test it. If you stick a cable in(with no signal going to it - 0v) and the synth starts to drone, it's probably s-trig.

Pitch, I think, would probably be 1v/Oct. I would think a mod would be 1v/Oct, but it may be easily compensated for if it's 1.2v. It depends what you use for external control. The same goes for s-trig. Many have a setting to switch from v-trig(standard) to s-trig.

You can find the Moog service bulletin that has their recommended mods here. They may have followed this. Be sure to note your serial number as the mods will differ depending on this.
Old 22nd February 2014
  #7
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Label are just called Gate, Filter, VC. It's the early model. So I have to test it.
Old 22nd February 2014
  #8
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Well, the good thing is the mods are already done for you.

You may just be able to plug the one in of the cable to the Prodigy, leaving the other end unplugged. I think that would work. It'll still drone if it's s-trig. Fingers crossed it's v-trig. Not that it's a biggie if it isn't, though.
Old 22nd February 2014
  #9
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Quote:
Originally Posted by bebo View Post
Label are just called Gate, Filter, VC. It's the early model. So I have to test it.
One problem you may run into when trying to control vintage synths with modern MIDI>CV interfaces is not having enough juice to trigger the GATE. So whatever you get, make sure it can go above +5 for the GATE if necessary. As for the pitch CV, you should be fine though there could be some pitch tracking/calibration issues. The filter CV should be fine as well, although you may not get the full range with a max of +5V from the interface. There are ways to attenuate/boost voltage, though, with additional modules or utility boxes like the Moog CP-251.
Old 22nd February 2014
  #10
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Analog CV(control voltage) standards?-whisper.jpg



I know, I know....
Old 22nd February 2014
  #11
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haha, when you said this, I thought of this module:

STANDARDS

yes, there's standards, hahaha.

and synths that violate them in every way, sure, but most are fine.

yes some early synths were 1.2v/oct, eml and maybe some old rolands like others said. most rolands were the standard 1v/oct scheme though fortunately. Then there's korg/yamaha with the hz/v stuff.

also, early moog synths were 1v/oct but they start at F instead of C which is enough to mess up your day a little if you're not expecting it. At least the scaling will be OK.

Quote:
Originally Posted by bebo View Post
And if I have an old Moog Prodigy that was modfied with CV by somebody? What voltage would you use? I have no information about the mod.
I actually had an early prodigy and modded it for CV myself. That F instead of C thing I just mentioned? Yeah, it's that. That's almost definitely going to be an issue. Used to drive me nuts at first, but my kenton unit I had at the time could set an offset, it was just somewhat annoying if you wanted to use it with another synth since I was constantly having to change the settings around. You will definitely want a CV/Gate converter that supports offsetting by X amount of semitones, so you can correct for that. It will be 1/v oct otherwise though. I can't recall the gate setup, but honestly, you can build gate to s-trig cables with just a single capacitor and a resistor, it's a piece of cake to convert gates most of the time, the CV is the part you need to worry about more than anything, otherwise it will just be out of tune or playing the wrong notes.
Old 23rd February 2014
  #12
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Quote:
Originally Posted by Xero View Post
also, early moog synths were 1v/oct but they start at F instead of C which is enough to mess up your day a little if you're not expecting it.
That's interesting about problems with the Moog beginning on F. My Promars also begins on F and I never had any problems using my Kenton MIDI>CV interface. I did have to tweak the v/oct setting a bit, but otherwise no major offsets were necessary. I wonder what makes the Moog behave differently.

I did have problems, though, using my early revision Dark Time with the Promars. It could only output a +5V GATE and the Promars needs about +8V. The newer Dark Times now have a jumper inside the unit you can switch around for a +12V GATE.
Old 23rd February 2014
  #13
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Xero, have you seen this on other Moogs? I haven't, not that I've seen close to them all. My Source and Rogue don't. Maybe that it didn't have CV or the mods? Or maybe it's just earlier Moogs?

Also, it sounds like you've passed the Prodigy on. Any complaints or just a personal taste issue? There's one locally taunting me. No CV but I can handle the mods. I'm sure as hell not buying an 80$ kit from Kenton when I can do it myself for >$10. Geez, was it that expensive when you got it?

Mad respect and I hope I don't sound too critical. Just curious.
Old 23rd February 2014
  #14
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Quote:
Originally Posted by bil_g View Post
Xero, have you seen this on other Moogs? I haven't, not that I've seen close to them all. My Source and Rogue don't. Maybe that it didn't have CV or the mods? Or maybe it's just earlier Moogs?

Also, it sounds like you've passed the Prodigy on. Any complaints or just a personal taste issue? There's one locally taunting me. No CV but I can handle the mods. I'm sure as hell not buying an 80$ kit from Kenton when I can do it myself for >$10. Geez, was it that expensive when you got it?

Mad respect and I hope I don't sound too critical. Just curious.
This was on a early prodigy that didn't come with factory cv/gate inputs, so it's likely the circuitry inside wasn't ever really intended to interface with other things. I'm pretty confident in saying it's only on earlier moogs though. I believe model d's also have this same issue. Source and rogue came later.

I traded the prodigy for a modified yamaha cs-30 w/sequencer trigger input and some cash. I had sold my cs-10 which I loved because I planned on using the money for a cs-30, which together with the trade of a prodigy got me the cs-30 I wanted. I don't know, I just never really liked the prodigy cause I wanted a model d and I felt like it was a cheap substitute. I did kind of like the crazy osc sync stuff it could do, but, it just didn't get much use in the end, I found myself going back to other synths instead of it. I also sold my sh-2 for the same reason, it's often lauded here as an "awesome 70s bass minimoog substitute" or something, but to me it just was boring, the filter was boring, etc, the only thing I liked it for was those warbly 70s sounding leads but even at that it wasn't that great. I'd take my sh-101 over that any day. This is all opinion of course, I know plenty of people who still say the sh-2 is awesome, but for me, it just wasn't there. I like synths with more character.

Anyhow, I ended up building a 5u modular which is definitely very "moog" inspired, including a moog ladder filter clone I built myself, so that has me a little tied over on the moog lust for now, but I still want a model D at some point. It's just getting hard to justify purchases anymore since I've not even used my equipment in longer than I'd like to admit, and I've got enough of it to make many people here jealous, none the less when it's sitting around doing nothing. It's not something I'm proud of I just haven't been very inspired lately. Been almost hoping I might find someone local to team up with at some point, but who the heck knows...my other side projects with electronics have also kind of distracted me a bit, I'm still building a yusynth dual gate width/delay module I etched my own pcb's for, but I've been lazy with that project as well...

now that i have the modular, I only really keep monosynths that have oodles of character, and the prodigy didn't have the mojo in my book. My EDP Wasp? I'll never part with that. My Sh-101? Never! my whiteface Odyssey? oh hell no that's not going anywhere, well, unless I got a 2600 maybe! but the prodigy just never stood out as much for me...the model d lust was just too great to justify keeping a synth I didn't really truly want to begin with.

And fwiw I did pay for the overpriced kenton kit, mostly cause I was somewhat new with electronics/upgrades at the time and wasn't as confident as I am now. If I recall, it had some circuitry shrink-wrapped inline with the one wire, to convert v-trig to s-trig, and all the instructions were pretty easy to follow, with photos and all that. So that's one perk of the kenton kit: it's good for n00bs, lol.

Quote:
Originally Posted by maisonvague View Post
That's interesting about problems with the Moog beginning on F. My Promars also begins on F and I never had any problems using my Kenton MIDI>CV interface. I did have to tweak the v/oct setting a bit, but otherwise no major offsets were necessary. I wonder what makes the Moog behave differently.

I did have problems, though, using my early revision Dark Time with the Promars. It could only output a +5V GATE and the Promars needs about +8V. The newer Dark Times now have a jumper inside the unit you can switch around for a +12V GATE.
It's not so much that there's a problem using it with the kenton, it's more so that it's annoying to go from using the prodigy to another synth that's not C as F with the kenton interface, and constantly having to re-adjust the settings, and/or select a different saved "preset" setting on the kenton unit. It's just tedious, that's all. It's not hard or impossible by any means. It's slightly more annoying than having to switch from v/oct to hz/v, since you have to remember the correct offset. If the prodigy was the only synth you ever used it with, I'm sure it'd be fine, but I had enough synths to max out the kenton pro-2000 at the time, which I later sold since my cirklon has even more cv/gate i/o.

For the gate voltage not enough issue, in that particular case, you could try the 'ol stick a battery inline with the gate signal trick. You could probably use a small 3.6v lithium cell inline to bump the voltage from 5v to 8v, no problem, since the 3.6v won't be enough to trigger it by itself otherwise....
Old 23rd February 2014
  #15
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Yeah, earlier Moogs. Thanks for the detailed response. I'm in the same place, just not feeling it right now. Too bad I don't live anywhere near you. We could combine our mehs into one super-meh. Yeah, trying to fix some broken synths to get me motivated.

I'd trade my CS-15 and 10 for 30 and don't get me started on the SH-101. Got one for free and traded it for $25 towards a drum machine, I think. It was the late 80's. Still. It doesn't hurt as bad as the Matrix-12 I found in a friends shop for $500 in 91, though. He listed it as broken because the midi out jack had broken loose. I remember I had $181 dollars to my name. Ugh.

Totally understand about the kenton kit. A couple of years ago, I'd have done the same. I bought the kits for the Rogue and CS-10 filter quite a few years ago.

I'm thinking of passing on the Prodigy. I mean, I have a Source. Is it gonna be that different? Sure it has knobs, but I gotta agree with you. It's gotta have some different character than what I've already got. Otherwise, it's just an "investment" purchase, at best, and will probably just sit around after the initial glow wears off.

Thanks.
Old 23rd February 2014
  #16
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Quote:
Originally Posted by bil_g View Post
Yeah, earlier Moogs. Thanks for the detailed response. I'm in the same place, just not feeling it right now. Too bad I don't live anywhere near you. We could combine our mehs into one super-meh. Yeah, trying to fix some broken synths to get me motivated.

I'd trade my CS-15 and 10 for 30 and don't get me started on the SH-101. Got one for free and traded it for $25 towards a drum machine, I think. It was the late 80's. Still. It doesn't hurt as bad as the Matrix-12 I found in a friends shop for $500 in 91, though. He listed it as broken because the midi out jack had broken loose. I remember I had $181 dollars to my name. Ugh.
Yeah, it's worth it IMO, it can almost act like two separate synths entirely if you want it to, though the layout of the cs-30 can be a challenge to get used to, but it sounds so crazy, with the built in sequencer and all it's crazy routings its almost as powerful as many semi-modular synths, but actually taking full advantage of all that is the challenge, another synth I could probably use to spend a lot more time with.


lol, another reason i'm not buying many synths right now is that i didn't stop til it was well into the negatives. I've justified many good deals that way, but also some not so great deals, now it's like how much interest do I end up paying versus any "deal" i might have saved money on hah. I've usually done OK but I've almost come to a complete halt on gear purchases as of late. I still really want a cs-80 badly, after a lot of searching and consideration it's really the only one I'm missing that I really care about, there's a few oberheims and a memorymoog would be nice, but, I've got enough other polys to cover similar territory, cs-80 is almost a league of it's own....it's almost absurd to me to even want such a ridiculous synth but I'm committed at this point to owning and maintaining one at some point, but it's not going to be any time soon.

Quote:
Originally Posted by bil_g View Post
Totally understand about the kenton kit. A couple of years ago, I'd have done the same. I bought the kits for the Rogue and CS-10 filter quite a few years ago.

I'm thinking of passing on the Prodigy. I mean, I have a Source. Is it gonna be that different? Sure it has knobs, but I gotta agree with you. It's gotta have some different character than what I've already got. Otherwise, it's just an "investment" purchase, at best, and will probably just sit around after the initial glow wears off.

Thanks.
honestly, if you have a source already, then definitely don't even bother with the prodigy, everything i've read says the source is probably the best sounding moog monosynth next to the minimoog, but I couldn't speak to that. I'm trying to trade/sell my prophet 5 rev3.3 for a model d, though i'm considering some other ideas too, but we'll see what happens.
Old 23rd February 2014
  #17
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Quote:
Originally Posted by Xero View Post
I also sold my sh-2 for the same reason, it's often lauded here as an "awesome 70s bass minimoog substitute" or something, but to me it just was boring, the filter was boring, etc, the only thing I liked it for was those warbly 70s sounding leads but even at that it wasn't that great.
I would be one of those lauding the SH-2. I love that thing! Yes, it's simple... and yes, the filter is a bit weak -- especially as you increase resonance -- but it's got a great tone that pleases my ears. It's a bit like the taste of a favorite wine or beer -- it just suits me. I also like the fact that the SUB OSC is divided down from OSC1: it makes three OSC bass/lead patches sound more solid and less phasey.

Quote:
For the gate voltage not enough issue, in that particular case, you could try the 'ol stick a battery inline with the gate signal trick. You could probably use a small 3.6v lithium cell inline to bump the voltage from 5v to 8v, no problem, since the 3.6v won't be enough to trigger it by itself otherwise....
Thanks, but I decided to go the cheaper route and just buy another Dark Time.
Old 4th March 2014
  #18
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I'm confused regarding the 1V/Octave standard. With a range of 5V, the most you can get is 60 notes. How would one go about accessing notes in the 60+ range? Does the 1V/octave scheme extend up to 6, 7, 8, 9, 10V?
Old 4th March 2014
  #19
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Quote:
Originally Posted by sequency View Post
I'm confused regarding the 1V/Octave standard. With a range of 5V, the most you can get is 60 notes. How would one go about accessing notes in the 60+ range? Does the 1V/octave scheme extend up to 6, 7, 8, 9, 10V?
The short answer, yes.

The long answer:
Back in the day, many analog synths couldn't scale that well to begin with so having much more notes than that wasn't very practical without major tuning issues at either end of the range. Now-a-days, there's definitely oscillators that can scale a lot better over a larger range, and many can take 10v range in some form or another.

However, even today getting scaling proper over much more than 5-6 octaves is somewhat uncommon, and usually not that necessary. Most people are not playing their modular and/or monosynths with an 88-key controlller, and many of those instruments (monosynths in particular) usually had quite small keybeds to begin with. Most analog polysynths had 61 keys max....a few had 72.

Most oscillators can be adjusted up or down, either via octave selectors or frequency knob, so you have a wider actual range, but only can play a sub-sections of it at a time. So you're basically still playing over that 0-5v range, but you're starting at a different point, perhaps adding a voltage offset of some kind.

I have the jupiter 8 service manual handy and a quick peek shows them talking about this very thing - the synth has a 96 note range total, but 61 only keys, so with the octave/frequency selector you're selecting 61 notes within that 96 note range, and it states the range is from 0v to 9v, with the octave switches likely just adding some voltage offset to make that range from say, 4-9v, or 0-5v, or somewhere in between. That said, I suspect many other polysynths have a similar arrangement.

Also, some (most?) oscillators will take negative voltage as well. In that case you'd be able to go above or below the selected range with a -5v/+5v 10v range. I use this trick on my SSL VCO to get super slow LFO's out of it. You can actually feed it negative voltage and go below what the knob on the front lets you select!
Old 4th March 2014
  #20
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What Xero said ...but I have to say this is one of those places where Silent Way/ES hardware can push past that. I can normally get 8-9 solid octaves out of the SEMs(old and new), Moogs, and SCI. They usually go from -2v to 8v. The top octave or two can be sketchy. No offset needed, though. I can even get 7+ octaves out of a CS-15. I could've grabbed another octave or two but, with the CS, I actually "programmed" the voltage for each key over those 7+ octaves - took about 1 1/2hrs. I figured that was plenty and, like Xero mentioned, not many need 88 keys. Sure, since my controller has only 61 keys, I have to use it's octave buttons but it's not offsetting the voltage, just the midi. IOW, I don't have to touch the synth.
Old 5th March 2014
  #21
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Quote:
Originally Posted by Xero View Post
The short answer, yes.

The long answer:
Back in the day, many analog synths couldn't scale that well to begin with so having much more notes than that wasn't very practical without major tuning issues at either end of the range. Now-a-days, there's definitely oscillators that can scale a lot better over a larger range, and many can take 10v range in some form or another.

However, even today getting scaling proper over much more than 5-6 octaves is somewhat uncommon, and usually not that necessary. Most people are not playing their modular and/or monosynths with an 88-key controlller, and many of those instruments (monosynths in particular) usually had quite small keybeds to begin with. Most analog polysynths had 61 keys max....a few had 72.

Most oscillators can be adjusted up or down, either via octave selectors or frequency knob, so you have a wider actual range, but only can play a sub-sections of it at a time. So you're basically still playing over that 0-5v range, but you're starting at a different point, perhaps adding a voltage offset of some kind.

I have the jupiter 8 service manual handy and a quick peek shows them talking about this very thing - the synth has a 96 note range total, but 61 only keys, so with the octave/frequency selector you're selecting 61 notes within that 96 note range, and it states the range is from 0v to 9v, with the octave switches likely just adding some voltage offset to make that range from say, 4-9v, or 0-5v, or somewhere in between. That said, I suspect many other polysynths have a similar arrangement.

Also, some (most?) oscillators will take negative voltage as well. In that case you'd be able to go above or below the selected range with a -5v/+5v 10v range. I use this trick on my SSL VCO to get super slow LFO's out of it. You can actually feed it negative voltage and go below what the knob on the front lets you select!
That makes sense that there wouldn't really be a need to go more than 60 keys since most monosynth keyboards are limited. But, wouldn't an external control voltage be independent from the 60 note limitations? It sounds like application of the voltage range and how it relates to the sound that is generated by the oscillator varies wildly. Is that why you mention that you can control what the range is on your synth? Is that how most synths handle the lack of a standard?

Say, for example, if you want note C4, it could be 0V, 5V, 10V right? And whatever synth you are using will be able to adjust accordingly? So if you give the synth 5V, and you want 5V to be note C4, then you change the scale. But, if whatever is sending the CV is on a different scale and it is sending 10V, then you adjust the synth again to give it C4. Is that right?

Or is the adjustment usually made on the device that is sending the CV?
Or do devices that use different voltage scales just not work together and you just kind of forget about putting two devices together that have different voltage scales?

With such a wide range of possible voltages, I guess synths are built to withstand weird and different voltage being plugged into the CD jack? I mean, I don't think anyone is going to be applying really high voltages, but seems like they would be engineered to accomodate something like -15V to +15V?

I googled the Jupiter 8 manual. Am I correct in understanding that you cannot control the oscillators with external devices?

Forgive me for all the questions, I unfortunately don't own any synths so I lack real world experience with oscillators and I've only recently started learning about how it all works. Needless to say its all extremely fascinating.
I should really just get a synth and find out.
Old 5th March 2014
  #22
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The 5V standard does not mean a system is limited to ranges of only +/-5 volts. The Doepfer A-100 system e.g. has a range of -12v to +12v. Pitch CV commonly has a wider range in order to accommodate the range of possible pitches. If C3 is 0v a range of -3v to +7v would cover the entire range of pitches set by the MIDI standard (i.e. 10v). Also, even when using a 5v standard most designers allow for higher voltages just to be safe. For example, sending a device a +12v GATE instead of a +5v GATE should not short the device. But still, it's something to take care about when mixing modules and CVs because you don't always know what a device can handle unless that info is published -- and even then you can get lost in the moment and overload something by sending it too much CV -- especially when using things like CV mixers and stackable cables.
Old 5th March 2014
  #23
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Quote:
Originally Posted by sequency View Post
That makes sense that there wouldn't really be a need to go more than 60 keys since most monosynth keyboards are limited. But, wouldn't an external control voltage be independent from the 60 note limitations? It sounds like application of the voltage range and how it relates to the sound that is generated by the oscillator varies wildly. Is that why you mention that you can control what the range is on your synth? Is that how most synths handle the lack of a standard?
Sure, if you had a midi to cv converter or something, it could certainly do a larger range than 60 notes. There's no guarantee the synth will actually scale well over such a large range though, chances are early analogs (say, early arps and early moogs and such) will struggle a bit with scaling a large range correctly.

I wouldn't really say it's "lack of a standard." It's actually a pretty standard thing for synths to have a wider note range than the amount of keys. The synths just have an octave or frequency selector, they're essentially just adding voltage to whatever range the keyboard supports: so if your keyboard supports a 0-5v range, and you flip the octave switch up to +1, it might now be a 1-6v range instead, and if you flip it up +2, it might be a 2-7v range instead. You could still potentially get the full range from external control on a variety of those settings, if you're applying both positive and negative voltage....

Quote:
Originally Posted by sequency View Post
Say, for example, if you want note C4, it could be 0V, 5V, 10V right? And whatever synth you are using will be able to adjust accordingly? So if you give the synth 5V, and you want 5V to be note C4, then you change the scale. But, if whatever is sending the CV is on a different scale and it is sending 10V, then you adjust the synth again to give it C4. Is that right?
Well, depending on how the frequency/octave is set, C4 could be any number of voltages, so yeah, that's basically true.

Quote:
Originally Posted by sequency View Post
Or is the adjustment usually made on the device that is sending the CV?
Or do devices that use different voltage scales just not work together and you just kind of forget about putting two devices together that have different voltage scales?
It can be made on that end too, though I generally only do that to correct for calibration issues. Honestly, sometimes you have to just experiment to get things right. Not all synths will react the same way. And yes, devices on different voltage scales won't work together: IE: Yamaha and Korg synths that use HZ/V will not work well with 1v/oct synths at all. However, generally if it's 1v/oct it's going to be fine, perhaps having to tweak the frequency on one end or the other to get it just right.

However, not all synths just have a perfect +/- 1v octave selector thing - some synths, like say an arp odyssey, you literally need to have a tuner or something to even get the frequency set correctly, even on it's own keyboard...it's all manual, just a slider. It does have a "octave switch" in addition to that, that lets you go +/- 1 octave without having to fiddle with the frequency sliders, but anything outside of that octave switch, you're going back to the frequency slider.

And on top of that - sometimes external control won't be exactly the same as the synth's keyboard's CV. So, you might find that C4 is fine on the odyssey's keyboard, but c4 from your midi to cv converter might be off, then you'll have to adjust the frequency of the odyssey and/or use your midi->cv device's calibration to correct for it. Again, you sometimes have to experiment to get this stuff right. You can often make slight adjustments like that in a variety of different ways.

Quote:
Originally Posted by sequency View Post
With such a wide range of possible voltages, I guess synths are built to withstand weird and different voltage being plugged into the CD jack? I mean, I don't think anyone is going to be applying really high voltages, but seems like they would be engineered to accomodate something like -15V to +15V?

I googled the Jupiter 8 manual. Am I correct in understanding that you cannot control the oscillators with external devices?

Forgive me for all the questions, I unfortunately don't own any synths so I lack real world experience with oscillators and I've only recently started learning about how it all works. Needless to say its all extremely fascinating.
I should really just get a synth and find out.

Jupiter 8 does have cv/gate input actually - but it only controls one voice. I was mostly referring to it's internal circuitry. Mine's got encore midi so I don't even bother with cv on it half the time...

Most modular synths will have over-voltage protection of some sort. I wouldn't really worry about it too much. Honestly, I wouldn't really even be worrying about any of this at all unless you actually have multiple synths that you're trying to interface together. And yes, you really should just get a synth and find out. Preferably one that's 1v/oct (so not a korg or yamaha...even though ms-20 seems like a nice semi-modular choice, the hz/v scheme is non-standard) If you really want to learn fast, don't even bother with monosynths, just get a modular or at least a semi-modular, you will figure it out. Half of this stuff probably won't even matter to you very much at first - it's unlikely you'll run into any weird scaling issues or anything if you're starting out with a current-ish modular synth setup or what not...
Old 5th March 2014
  #24
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Quote:
Originally Posted by Xero View Post
For the gate voltage not enough issue, in that particular case, you could try the 'ol stick a battery inline with the gate signal trick. You could probably use a small 3.6v lithium cell inline to bump the voltage from 5v to 8v, no problem, since the 3.6v won't be enough to trigger it by itself otherwise....
Hi everyone,

I've been running into this same problem myself recently. I'd love to sequence some of my older synths (ARP Odyssey, SH5) that need more than 5V to trigger the gate from my SH101 (love that sequencer), which only puts out 5V for gate.
Could you point me to somewhere where this battery trick is explained in detail (I'm not very well versed in electronics) or does anyone know of another way to convert 5V gate into 7.5 or 10V?

Thanks!
Kulder
Old 5th March 2014
  #25
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There are probably modules out there that can convert 5V gate to something higher, but you can also do it easily with a comparator IC, op-amp, or a couple transistors.

I always wondered about CV pitch "standards". v/oct makes sense, but what is the starting point? What voltage is supposed to be middle C, for example? What note/pitch should you get if you supply a +3V pitch CV? I think that's where different synths/manufacturers vary widely.

I have to wonder, when someone designs a MIDI-CV converter, how they decide what their starting point on the scale is, or what voltage gets spit out when it receives a middle-C note-on message.
Old 5th March 2014
  #26
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Xero's Avatar
Quote:
Originally Posted by Kulder View Post
Hi everyone,

I've been running into this same problem myself recently. I'd love to sequence some of my older synths (ARP Odyssey, SH5) that need more than 5V to trigger the gate from my SH101 (love that sequencer), which only puts out 5V for gate.
Could you point me to somewhere where this battery trick is explained in detail (I'm not very well versed in electronics) or does anyone know of another way to convert 5V gate into 7.5 or 10V?

Thanks!
Kulder
There's really not much to it. You literally splice the battery into the positive side of the cable, which is the tip of the 1/4" connector. You'd want the positive side of the battery going towards the synth, and the negative side towards the sequencer. Of course, once the cable is made, that's just a simple matter of reversing the cable if you got it backwards.

You could easily modify a 5v gate into whatever you want with a modular synth, there's plenty of modules which can add voltage offsets and whatnot.
Old 5th March 2014
  #27
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Xero's Avatar
Quote:
Originally Posted by kpatz View Post
There are probably modules out there that can convert 5V gate to something higher, but you can also do it easily with a comparator IC, op-amp, or a couple transistors.

I always wondered about CV pitch "standards". v/oct makes sense, but what is the starting point? What voltage is supposed to be middle C, for example? What note/pitch should you get if you supply a +3V pitch CV? I think that's where different synths/manufacturers vary widely.
Generally, most 1v/oct synths are 0v=C, which means 1v=C, 2v=C , and you guessed it, 3v=C too! The only exceptions I know of are early moogs and I think someone mentioned the promars...they have 0v=F instead. However, this is pretty rare, and it doesn't vary as widely as you'd suggest. Of course, middle C itself could be at 1v, 2v, 3v, etc, depending on your octave setting on the synth, but it's never going to just going to be like 2.3v or some random value like that, well, unless your synth is horribly out of tune.
Old 5th March 2014
  #28
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maisonvague's Avatar
 

Quote:
Originally Posted by Xero View Post
Generally, most 1v/oct synths are 0v=C, which means 1v=C, 2v=C , and you guessed it, 3v=C too! The only exceptions I know of are early moogs and I think someone mentioned the promars...they have 0v=F instead.
I mentioned the Promars earlier as having a keyboard which begins with F, but C is still 0v, 1v, 2v, etc meaning no offset is necessary when using a standard MIDI>CV interface.
Old 5th March 2014
  #29
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Xero's Avatar
Quote:
Originally Posted by maisonvague View Post
I mentioned the Promars earlier as having a keyboard which begins with F, but C is still 0v, 1v, 2v, etc meaning no offset is necessary when using a standard MIDI>CV interface.
Oh...that's not the same thing then! Yeah, on the old moogs, 0v is actually F.
Old 28th July 2015
  #30
Most commonly standard is: -15V -12V 0V +5V +12V +15V as power supply voltages.

Triggers and gates are usually TTL level (+5V) for easy interfacing with oldskool microcontrollers and logic chips.

All analog modulation signals should be symmetrically usable.
Range depends from module to module clipping levels and drop out voltages are diffrent from circuit to cirquit.

This means from -10 to +10 volt would be realistic
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