Would you prefer one PCB with 3 VCOs a la JH-5A, or 1 VCO per PCB with more features |
One PCB with Oscillator Driver and 3 VCO cores (like JH-5A - cheap!) |
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60% |
[ 62 ] |
1 PCB = 1 VCO (with many waveforms and inputs) |
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39% |
[ 41 ] |
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Total Votes : 103 |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sun Dec 07, 2008 12:09 pm Post subject:
Living VCOs |
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I got several requests for a VCO like I have in my JH-5, something that doesn't have the focus on precision but on character, with "linear detuning", and some of that early Moog and EMS character (without being a clone):
http://jhaible.heim.at/jh5/jh5.html
The main reason why I hesitated so long was as simple as it was embarrassing: I couln't find my design documents - I must have lost them in moving houses some years ago. The prospect was that'd I'd have to reverse-engineer my own prototype if I wanted to offer a PCB for this ...
But some days ago, I found my PSpice simulation files, which show the main parts of the VCO and VCO driver circuits in a form that must be very close to what I've actually built in the JH-5.
So, suddenly the possibility is there ...
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) Last edited by jhaible on Wed Dec 10, 2008 4:13 pm; edited 1 time in total |
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synthetic
Joined: Jun 02, 2007 Posts: 76 Location: Glendale, CA
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Posted: Sun Dec 07, 2008 12:45 pm Post subject:
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Yes, please. I've been searching for something like this. I'm in for two or three boards depending on cost. |
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vtl5c3
Joined: Sep 08, 2006 Posts: 425 Location: PDX
Audio files: 13
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Posted: Sun Dec 07, 2008 2:33 pm Post subject:
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I'm interested. Are we talking one VCO per board or more?
Romeo |
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Luka
Joined: Jun 29, 2007 Posts: 1003 Location: Melb.
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Sun Dec 07, 2008 4:02 pm Post subject:
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vtl5c3 wrote: | I'm interested. Are we talking one VCO per board or more?
Romeo |
At the moment, we're just talking about a possibility.
I don't have any specific plans yet.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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numbertalk
Joined: May 05, 2008 Posts: 992 Location: Austin, TX
Audio files: 5
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Posted: Sun Dec 07, 2008 6:09 pm Post subject:
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Sounds interesting. Definitely curious. |
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guitarfool
Joined: Feb 26, 2007 Posts: 160 Location: Maryland
Audio files: 8
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Posted: Sun Dec 07, 2008 8:40 pm Post subject:
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Wow - great news! I'd be up for doing several. I have been planning on doing the "linear detune SEM VCO mod" (from Roy Tate's website) on a couple of MOTM 310's (since they're basically the same topology), but this would be better |
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machine.cuisine
Joined: Jul 20, 2007 Posts: 61 Location: ks
Audio files: 4
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Posted: Sun Dec 07, 2008 10:11 pm Post subject:
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I can never turn down a VCO - especially a "living" one. You have my support. |
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johans121
Joined: Jun 19, 2007 Posts: 178 Location: Huntsville, AL (USA)
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Posted: Mon Dec 08, 2008 10:05 am Post subject:
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As long as I have money to blow, you'll continue to receive it _________________ Don't feed me Indian, you WILL regret it!
-Jim |
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aerogramma
Joined: Feb 27, 2008 Posts: 156 Location: Roma, Italy - London, UK
Audio files: 13
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Posted: Mon Dec 08, 2008 11:48 am Post subject:
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definetely interested
would be nice to hear also crude samples, without reverb
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fluxmonkey
Joined: Jun 24, 2005 Posts: 708 Location: cleve
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Posted: Tue Dec 09, 2008 10:43 am Post subject:
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as always, I'm in... put me down for 4. you're a hero.
bbob _________________ www.fluxmonkey.com |
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Scott Stites
Janitor
Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
Audio files: 96
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Posted: Tue Dec 09, 2008 10:54 am Post subject:
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I'd also like to hear crude samples, with reverb! _________________ My Site |
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
Audio files: 54
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Posted: Tue Dec 09, 2008 3:05 pm Post subject:
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aerogramma wrote: | would be nice to hear also crude samples, without reverb |
I've been asking for that for months, as well as for demos of the ARP VCO that is supposed to be "shrill".
Why do you suppose no one is willing to do this?
Ian |
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djthomaswhite
Joined: Nov 22, 2007 Posts: 140 Location: Orange, CA
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Posted: Tue Dec 09, 2008 11:59 pm Post subject:
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I'd like to build this as well. 3 in one rack with Vernier dials like on your JH-5 _________________ Thomas
www.naturalrhythmmusic.com/diy.html |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Wed Dec 10, 2008 4:02 am Post subject:
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Hi Jurgen
I have a design question concerning this constant Hz offset that I think is very interesting. I know the schematic you designed for the SEM VCO using an extra cap in series with the VCO timing capacitor.
If say the VCO has a classical servo OPAmp exponential current converter, could it be that by simply adding an offfset voltage on the lin FM input of the servo circuit (the inverting input of the OPA) one could get the same effect or is there an obvious difference with what you proposed ?
Thanks in advance
Yves _________________ Yves |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Wed Dec 10, 2008 4:45 am Post subject:
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yusson wrote: | Hi Jurgen
I have a design question concerning this constant Hz offset that I think is very interesting. I know the schematic you designed for the SEM VCO using an extra cap in series with the VCO timing capacitor.
If say the VCO has a classical servo OPAmp exponential current converter, could it be that by simply adding an offfset voltage on the lin FM input of the servo circuit (the inverting input of the OPA) one could get the same effect or is there an obvious difference with what you proposed ?
Thanks in advance
Yves |
Yes, there's a difference.
(And the new implementation isn't like that SEM modification either.)
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Wed Dec 10, 2008 4:54 am Post subject:
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jhaible wrote: | Yes, there's a difference.
(And the new implementation isn't like that SEM modification either.)
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I am even more intrigued !
Can you tell us what is the benefit of your design compared to what I was referring to in my previous message ? I am definitely interested...
: _________________ Yves |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Wed Dec 10, 2008 5:02 am Post subject:
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yusson wrote: | jhaible wrote: | Yes, there's a difference.
(And the new implementation isn't like that SEM modification either.)
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I am even more intrigued !
Can you tell us what is the benefit of your design compared to what I was referring to in my previous message ? I am definitely interested...
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I don't think that a voltage offset in the servo loop causes what I mean with linear detuning. (I think it causes linear FM.)
I should have found a better word for what I mean, many years ago, I know.
"Linear" refers to the behaviour of Linear (V/Hz) VCOs, not to linear FM in exponential VCOs.
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Wed Dec 10, 2008 5:29 am Post subject:
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Quote: | "Linear" refers to the behaviour of Linear (V/Hz) VCOs, not to linear FM in exponential VCOs. |
Hi again Jurgen,
Pardon my ignorance but checking the MS20 VCO which operates as a linear V/Hz VCO, the keyboard CV and V/Hz input is directed to that very point (inverting input of IC3) ? I'd conclude that using a voltage offset would create a constant Hz offset, wouldn't I ? Do I misunderstand something ?
[EDIT] Ok I think I get the difference, the V/OCT input somehow modifies the range of offset from the linear modulation, the modulation stays linear but its extents is modified by the V/OCT input. And say if I increase from 1V on the V/OCT input this will double the range of the linear modulation... Thus a constant offset on the linear input will not result in a constant frequency offset if I apply 1V on the V/OCT input. Am I right ?
[/EDIT] _________________ Yves Last edited by yusynth on Wed Dec 10, 2008 5:59 am; edited 2 times in total |
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yusynth
Joined: Nov 24, 2005 Posts: 1314 Location: France
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Posted: Wed Dec 10, 2008 5:56 am Post subject:
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OK I ruled out the linear FM input.
The only other solution I foresee is to have a second current source/sink to feed the timing cap. This second source (or sink) being linearly controlled by an offset voltage. Thus the time cap receives the sum of the currents from the expo converter and from the linear current source.
Is it something like that ?
Yves _________________ Yves |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Wed Dec 10, 2008 6:36 am Post subject:
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yusson wrote: | OK I ruled out the linear FM input.
The only other solution I foresee is to have a second current source/sink to feed the timing cap. This second source (or sink) being linearly controlled by an offset voltage. Thus the time cap receives the sum of the currents from the expo converter and from the linear current source.
Is it something like that ?
Yves |
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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Electronicant
Joined: Feb 23, 2006 Posts: 81 Location: North
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Posted: Wed Dec 10, 2008 10:11 am Post subject:
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I´m in for 2-3 of these. |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Wed Dec 10, 2008 2:26 pm Post subject:
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johans121 wrote: | As long as I have money to blow, you'll continue to receive it |
i'm in the same boat |
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TekniK
Joined: Aug 10, 2008 Posts: 1059
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Posted: Wed Dec 10, 2008 2:36 pm Post subject:
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There is a probable possibility probably that i will buy several from u Juergen |
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jhaible
Joined: May 25, 2007 Posts: 2014 Location: Germany
Audio files: 24
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Posted: Wed Dec 10, 2008 2:44 pm Post subject:
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vtl5c3 wrote: | I'm interested. Are we talking one VCO per board or more?
Romeo |
That's a good question.
Depends on how many waveforms you need.
In the JH-5, there's only saw and pulse (with PWM) and one Oscillator Driver controlling 3 VCO cores. This can be very compact. Maybe (maybe!) 3 VCOs on a single 27 Euro PCB.
If you want full fledged VCOs with all waveforms and all kind of modulation inputs, it's probably one VCO per board.
Is there a way to add a poll on a thread that's already in use?
JH. _________________ "I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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