eml synthesizers

::: converting 1.2 volt/octave to 1 volt/octave :::

Hello, i was noticing some discussion about changing the EML 101 to 1v/octave...

is it possible to do this on the EML200 as well?

is it really just a resistor change? maybe a substitute for the 22k Swing resistor value?

or does the Center value need to change as well?

that would be a sweet mod!

Thanks!

Nick Z

I know the difference i just had heard hz/v mentioned for them. A guy playing his with a MS-20 etc.

On 2011-07-19 12:15 PM, "Nick Zampiello" <newallianceeast@...> wrote:

 

The 200 and 101 oscillators are a non-standard 1.20v/oct

hz/volt is more of a japan convention: korg, Yamaha, etc...

i can get mine to tune to other 1v/oct gear but its prone to drift as the controls are so course.

i was hoping to get a mod enacted with a fine tune VR so one of the swing inputs was always 1v/oct and could be calibrated as things settle and drift...

PS:

from WIKI:

http://en.wikipedia.org/wiki/CV/Gate#CV

CV

While the concept of CV (Control Voltage) was fairly standard on analog synths, the implementation was not. For pitch control via CV, there are two prominent implementations:

• Volts per octave. This standard was popularized by (if not created by) Bob Moog in the 1960s; it was widely adopted for control interfacing.One volt represents one octave, so the pitch produced by a voltage of 3 V would be one octave lower than that produced by a voltage of 4 V. Notable followers of this standard include Roland, Moog, Sequential Circuits, Oberheim and ARP.

• Hertz per volt. This method (used by most but not all Korg and Yamaha synths) represented an octave of pitch by doubling voltage, so the pitch represented by 2 V would be one octave lower than that represented by 4 V, and one higher than that represented by 1 V.

The following example table demonstrates some notes and their corresponding voltage levels in both implementations (this example uses 1 V/octave and 55 Hz/V):

z


 

NEW ALLIANCE EAST!!!!


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http://www.myspace.com/newallianceaudio

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From: Prosper Prodaniuk <prosperp@...>
To: emlsynth@yahoogroups.com
Sent: Tue, July 19, 2011 2:54:33 PM
Subject: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave

 

Maybe in this someone can answer whether or not the 200 (and 100) are HZ/V as opposed to V/OCT a...

> The 200 and 101 oscillators are a non-standard 1.20v/oct

Are you sure about the 200? The schematic I've seen looks
like a V/Hz oscillator. Or was there a later version of the 200
(201?)

Steve

From: emlsynth@yahoogroups.com [mailto:emlsynth@yahoogroups.com] On Behalf Of sprgroups@...
Sent: Wednesday, July 20, 2011 3:45 PM
To: emlsynth@yahoogroups.com
Subject: Re: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave

 

> The 200 and 101 oscillators are a non-standard 1.20v/oct

Are you sure about the 200? The schematic I've seen looks
like a V/Hz oscillator. Or was there a later version of the 200
(201?)

Steve

yeah the EML200's oscillators are hz/v.

--- On Thu, 7/21/11, Nick Zampiello <newallianceeast@...> wrote:

From: Nick Zampiello <newallianceeast@...>
Subject: Re: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave
To: emlsynth@yahoogroups.com
Date: Thursday, July 21, 2011, 8:48 AM

So, i knew something was confusing and i looked into my old emails...

dave wilson of NESM had explained it to me before and i just remembered it backwards:

"The Museum is doing well. The VCOs on the 200 are Hz/Volt, not Oct/Volt, so they can be made to

track your Korg MS-20 or your Yamaha CS-40M, but not an ARP or Moog synthesizer. The EML 101

has an output called "CM2" (Control Mode 2) that is a Hz/Volt output that can drive the 200's VCOs.

Older EML 101s have a CM3, same thing but high note priority for duophonic; More recent 101s have

a Sequencer input jack instead."

z

 

NEW ALLIANCE EAST!!!!


--------------------------------------

http://www.newallianceeast.com

http://www.newallianceaudio.com

http://www.myspace.com/newallianceaudio

http://www.c4rt.com

www.myspace.com/thecampaignforrealtime

From: George Mattson <axisair@...>
To: emlsynth@yahoogroups.com
Sent: Wed, July 20, 2011 8:40:28 PM
Subject: RE: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave

 

The 200 is basically just a bare integrator IC with a UJT, cap and diode network in the feedback loop. The center frequency and both swings are all summed together after their input resistors into the ame op amp input as the feedback network. The diode and UJT act as choppers to produce the sawtooth output from the integrator.

 

The output of the op amp goes to the 470 ohm output impedance resistor and capacitively coupled to the two outputs, which are hardwired to each other.

 

There's no current control, differentiation or exponential amplifier. So, it doesn't look like it was designed with any sort of scaling capacity in mind. 

From: emlsynth@yahoogroups.com [mailto:emlsynth@yahoogroups.com] On Behalf Of sprgroups@...
Sent: Wednesday, July 20, 2011 3:45 PM
To: emlsynth@yahoogroups.com
Subject: Re: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave

 

> The 200 and 101 oscillators are a non-standard 1.20v/oct

Are you sure about the 200? The schematic I've seen looks
like a V/Hz oscillator. Or was there a later version of the 200
(201?)

Steve

As far as I know there are two issues at play for HZ/V/Oct.

1 - The octave scaling everyone talks about. Technically you can calibrate one octave between the 101 and another V/Oct synth. You can luxury of getting say, a low C and a high C to be 'in tune'.

2 - Each note within that octave has to scale logarithmically, and this is actually the root of the problem. It's a separate conversion altogether. A V/Oct synth scales up in a linear fashion. A HZ/V/Oct synth scales up in a non-linear fashion, logarithmically, so the octave tuning has no bearing on what happens with all these notes in between. The 101 exponentially scales as you move up from one note to another so it will always be way out of tune until it reaches your calibrated 1.2V, then it's way off forevermore past your calibrated octave.

Hi Guys

I posted photos in 2007 of the schematics (http://groups.yahoo.com/group/emlsynth/photos/album/524942379/pic/list ) which I received from Dale Blake to make a VP-1 Voltage Processor back in 1985, I've one in my 101 and 500 and worked fine with my ROLAND MPU 101 MIDI to CV CONVERTER, ARP sequencer and Octave Cat allowing the EMLs to track the 1V octaves with no problems.

Robert

--- In emlsynth@yahoogroups.com, Nick Zampiello <newallianceeast@...> wrote:
>
> i never had any luck trying to get the EML to track to any hz/volt synth...
>
> it just can't scale that far beyond 1.2 v/oct...
>
> the way the controls are on mine it's almost impossible to keep it in tune
> scaled to 1v/oct with both osc in tune...
>
> maybe he was using the pitch tracker on the MS20 to make it chase the EML osc...
> the 'swing' on the ms20 pitch tracker can co from 0-2x or so i believe....
> maybe he tricked it into being in tune in a smaller range...
>
> hmmmmm.....
>
>
> z
>
> NEW ALLIANCE EAST!!!!
>
>
> --------------------------------------
>
> http://www.newallianceeast.com
>
> http://www.newallianceaudio.com
>
> http://www.myspace.com/newallianceaudio
>
> http://www.c4rt.com
>
> www.myspace.com/thecampaignforrealtime
>
>
>
>
> ________________________________
> From: Prosper Prodaniuk <prosperp@...>
> To: emlsynth@yahoogroups.com
> Sent: Tue, July 19, 2011 3:17:51 PM
> Subject: Re: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave
>
>
> I know the difference i just had heard hz/v mentioned for them. A guy playing
> his with a MS-20 etc.
> On 2011-07-19 12:15 PM, "Nick Zampiello" <newallianceeast@...> wrote:
> >
> >
> >
> >The 200 and 101 oscillators are a non-standard 1.20v/oct
> >
> >hz/volt is more of a japan convention: korg, Yamaha, etc...
> >
> >i can get mine to tune to other 1v/oct gear but its prone to drift as the
> >controls are so course.
> >
> >i was hoping to get a mod enacted with a fine tune VR so one of the swing inputs
> >was always 1v/oct and could be calibrated as things settle and drift...
> >
> >PS:
> >
> >from WIKI:
> >
> >http://en.wikipedia.org/wiki/CV/Gate#CV
> >
> >CV
> >While the concept of CV (Control Voltage) was fairly standard on analog synths,
> >the implementation was not. For pitch control via CV, there are two prominent
> >implementations:
> > * Volts per octave. This standard was popularized by (if not created by) Bob
> >Moog in the 1960s; it was widely adopted for control interfacing.One volt
> >represents one octave, so the pitch produced by a voltage of 3 V would be one
> >octave lower than that produced by a voltage of 4 V. Notable followers of this
> >standard include Roland, Moog, Sequential Circuits, Oberheim and ARP.
> > * Hertz per volt. This method (used by most but not all Korg and Yamaha synths)
> >represented an octave of pitch by doubling voltage, so the pitch represented by
> >2 V would be one octave lower than that represented by 4 V, and one higher than
> >that represented by 1 V.
> >The following example table demonstrates some notes and their corresponding
> >voltage levels in both implementations (this example uses 1 V/octave and
> >55 Hz/V):
> >z
> >
> >
> > NEW ALLIANCE EAST!!!!
> >
> >
> >--------------------------------------
> >
> >http://www.newallianceeast.com
> >
> >http://www.newallianceaudio.com
> >
> >http://www.myspace.com/newallianceaudio
> >
> >http://www.c4rt.com
> >
> >www.myspace.com/thecampaignforrealtime
> >
> >
> >
> >
> >
> ________________________________
> From: Prosper Prodaniuk <prosperp@...>
> >To: emlsynth@yahoogroups.com
> >Sent: Tue, July 19, 2011 2:54:33 PM
> >Subject: [emlsynth] Re: converting 1.2 volt/octave to 1 volt/octave
> >
> >
> >
> >
> >Maybe in this someone can answer whether or not the 200 (and 100) are HZ/V as
> >opposed to V/OCT a...
>