The Cyndustries List

I should have been clearer.  I used the middle setting for Range, which must
be your MEDIUM.  I did not use the LFO range.

John Loffink
The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com
The Wavemakers Synthesizer Web Site
http://www.wavemakers-synth.com


> -----Original Message-----
> From: The_Cyndustries_List@yahoogroups.com
> [mailto:The_Cyndustries_List@yahoogroups.com] On Behalf Of tuninghead
> Sent: Tuesday, February 28, 2006 12:11 PM
> To: The_Cyndustries_List@yahoogroups.com
> Subject: [The_Cyndustries_List] Re: ZO 1V/Octave calibration
> 
> Hi there John and other trackers,
> 
> John L., we repeated your measurements, but this time we used the
> appropriate range setting for low audio which is the MEDIUM range
> setting.  You are stretching the LFO range into boy's choir territory.
>  For the same frequency range you used, we measured our octave ratios at:
> 
> volts   ratio
> -1
> 0     2.009
> 1     2.003
> 2     2.007
> 3     1.996
> 4     1.999
> 5     1.989
> 6     1.981
> 
> This shows 6 great octaves and a usable 7th.  Now, why aren't there 10
> good octaves?
> 
> The topology of the Zeroscillator core is unlike any conventional VCO
> sawtooth or triangle core.  The current that runs the core is the
> result of arithmetic computations that are all performed in analog --
> most critically, a multiplication.  This multiplication (which I have
> covered in a previous post) does not exist in conventional VCOs and
> because of its very prescence, is a small source of error.  The
> multiplier used for this task is the finest one available in the free
> world, period.  Additionally, issues of dynamic range loom large in
> the design trade-offs that must be made to bring you the absolutely
> outrageous amount of modulation this oscillator offers.  Techniques to
> maximize accuracy are covered in the Zeroscillator manual.
> 
> We have 15V of power supply to work with (Euro versions have 12V).
> Everything has to happen within that space.  Improved accuracy can
> always be traded for modulation range.  The HIGH BIAS position
> provides 1V of bias and the LOW BIAS position provides about 0.2, if
> I'm remembering correctly.  This means in HIGH BIAS we can attain
> about 1000% modulation before the multiplier will be taxed for
> accuracy (at about 10V).  In LOW BIAS we get about 5000%.  Considering
> that 100% is the most you can ever get from a conventional VCO (and
> most designs restrict the range to far below that), this is pretty
> darn exciting.  The BIAS switch is not there to change frequency
> range.  It's there because of accuracy tradeoffs.   To get improved
> accuracy you could pump 5V into the LINEAR FM input to give the
> multiplier more to work with.  The accuracy will get better at the
> expense of the modulation range being reduced to about 200% which may
> still be enough for the sound you are looking for.
> 
> To answer another question, yes, a precision voltage reference is used
> for all critical internal voltages.  The power supply rejection was
> tested and found to be superior to the Modcan oscillator.  John Ross
> is responsible for adding to the design, the most comprehensive power
> supply cleansing I have ever seen on an EM module.  We could have just
> regulated down to +/-12V, but that too would have cost us range.
> 
> There have been other attempts at thru-zero, analog VCOs in the past.
>  None of them turned into products because although they did the FM
> thing, none of them tracked well enough to be accepted.  I found the
> ZO's tracking to be quite adequate to make any sound I desired along
> with a Modcan VCO as a modulator.  Personally, as a user, I have no
> complaints with the ZO's performance, and as an engineer, I have held
> nothing back about the ZO's operation and design tradeoffs.  We are
> doing something in analog that has been traditionally believed to be
> the sole property of digital and I believe we have pulled it off well.
> 
> In choosing an oscillator, one always compares features and specs, but
> comparing the ZO to a traditional oscillator is like comparing apples
> and oranges.  They're both fruits, but if you need citrus, an apple
> isn't going to cut it.  You can be about the measuring or about the
> music.  The Zeroscillator offers sounds that are unobtainable from any
> other commercially available analog module in the solar system.  It's
> up to each individual musician to decide what is important.  The units
> are flying off the shelves and the feedback we are getting from users
> ranges from sheer delight to ecstatic euphoria.
> 
> --Mark Barton
> 
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