The Cyndustries List

My results.

I used the preferred ZO setting for accuracy per the manual. I did not
adjust the ZO 1V/oct tracking trimmer.  It is at the factory setting.

Range switch: Lowest setting
Bias switch:  High
Tuning Knob in middle of range

Encore Expressionist used as the voltage source.  Both VCOs patched to
1V/oct jacks.  Measured frequency on sine out.  No other cables plugged in,
all modulation controls at minimum.  Both VCOs in the same cabinet running
from the same power supply.

I set the VCO tuning as accurately as I could to 120 Hz at the 2 volt input.
This is the reference frequency.

MOTM VCO calibrated by me recently.

Measurements with Extech Multimaster 560 5/6 digit DMM.  Voltage accuracy is
rated at +/- 0.03%.  Frequency accuracy is rated at +/- 0.008%.

ZO data

Desired Voltage	Input Voltage	Desired Frequency	Actual Frequency
Error (Hertz)	Error (percent)
-1	-1.0007	15	14.812	-0.188	-1.25%
0	-0.0034	30	30.16		0.160		0.53%
1	0.9940	60	60.308	0.308		0.51%
2	1.9915	120	119.99	-0.010	-0.01%
3	2.9887	240	238.16	-1.840	-0.77%
4	3.9862	480	472.2		-7.800	-1.63%
5	4.9837	960	934.25	-25.750	-2.68%
6	5.9820	1,920	1841.7	-78.300	-4.08%

MOTM-300 data

Desired Voltage	Input Voltage	Desired Frequency	Actual Frequency
Error (Hertz)	Error (percent)
-1	-1.0007	15	14.965	-0.035	-0.23%
0	-0.0034	30	29.958	-0.042	-0.14%
1	0.9940	60	59.954	-0.046	-0.08%
2	1.9915	120	119.96	-0.040	-0.03%
3	2.9887	240	239.89	-0.110	-0.05%
4	3.9862	480	479.68	-0.320	-0.07%
5	4.9837	960	958.23	-1.770	-0.18%
6	5.9820	1,920	1912.1	-7.900	-0.41%

For comparison, Synthesizers.com VCO data from their web site, not measured
by me, uses 128 Hz as based frequency.

Desired Frequency	Actual Frequency	Error Hertz	Error
Percent
32		32.07		-0.07		-0.22%
64		64.16		-0.16		-0.25%
128		128.2		-0.20		-0.16%
256		256.2		-0.20		-0.08%
512		511.9		0.10		0.02%
1,024		1023.2	0.80		0.08%
2,048		2046		2.00		0.10%
4,096		4094		2.00		0.05%
8,192		8236		-44.00	-0.54%
16,384	16778		-394.00	-2.40%

I hope the ASCII tables don't become too jarbled.

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 Richard
> Brewster
> Sent: Sunday, February 26, 2006 6:27 PM
> To: The_Cyndustries_List@yahoogroups.com
> Subject: Re: [The_Cyndustries_List] ZO 1V/Octave calibration
> 
> Thanks, Cynthia.  I found the trimpot easily.
> 
> I ended up with a setting close to the original factory setting. But I
> was not able to fix a problem of the ZO tracking sharp in the lower
> octaves of the high range. I started down this calibration road because
> I noticed that the ZO and the MOTM-300 being used as the FM source in
> the starter ZO patch were not tracking each other well.  The beats were
> quite noticable.  I spent a couple of hours taking measurements, after
> setting the 1V/oct trimpot.  Here's what I found.
> 
> I measured with a digital voltmeter and a digital frequency counter.
> For comparison I performed the same tests on the MOTM-300 VCO.  The
> results were all obtained by the same method and instruments, using the
> same power supply.  I created a 1V source by a mixer with bias (my own
> mixer-comparator) and measured for 1V at the 1V/oct input jack.  For
> each reading I dialed up a frequency, applied 1 volt and recorded the
> new frequency, which ideally is double for the next octave.  For the ZO
> I did this in all four combinations of High/Low Bias and High/Mid
> range.  I only measured what I could dial up that started in the audio
> range. Each number pair below represents the HZ value before and after,
> so 30/60 means 30HZ/60HZ.
> 
> Low Bias/Mid Range
> 30/60 - right on
> 60/119.8
> 
> Low Bias/High Range
> 30/66
> 60/123.2
> 120/241.5
> 240/480 - right on
> 480/957
> 
> High Bias/Low Range
> 30/60.2
> 60/120 - right on
> 120/239.7
> 240/478.4
> 
> High Bias/High Range
> 30/66
> 60/124
> 120/243
> 240/482
> 480/960 - right on
> 960/1916
> 1920/3825
> 
> MOTM-300
> 30/60 - right on
> 60/120 - right on
> 120/240 - right on
> 240/480 - right on
> 480/960 - right on
> 960/1918
> 1920/3834
> 
> The ZO tracking isn't bad, but it isn't great either.  The ZO starts out
> on the low end tracking more than one octave per volt (sharp), passes
> the sweet spot and starts going flat gradually.  By contrast the
> MOTM-300 tracks perfectly over about six octaves and then also start
> going a little flat.  Now this flatness on the high end may be by
> design, due to psycho-acoustic effects, I seem to recall. I'm not a
> music VCO expert. But sharpness on the low end isn't good.
> 
> For my ZO the tracking is accurate over at best about three octaves.
> The lower octaves track better in the low range and the higher octaves
> track better in the high range.  This was a useful finding.  Of course I
> tested only my own ZO, so I can't say whether this is the general
> character of a ZO or not.  Still, I would be interested to hear from
> other ZO owners whether they are able to replicate my findings.
> 
> -Richard Brewster
> 
> http://www.pugix.com
> 
> 
> 
> 
> 
> 
> 
> Cynthia Webster wrote:
> 
> >Hi Richard!
> >
> >First, please be quite certain that it is the ZO and not rather
> >that another oscillator (or keyboard) in your system being slightly
> off...
> >
> >The Zeroscillator 1volt/octave trimmer is located on the top
> >board where the power plugs in.   If you locate the logo
> >saying Cynthia CYN109-C and rotate the ZO so that this logo is
> >reading right side up, then the trimmer is the first one to the left,
> >(right after the Tempco).  It is a multi-turm trimmer laying flat.
> >
> >The other two trimmers next to it are for shaping the sine wave.
> >
> >We also have a precision Volt to the Octave Calibration Gadget
> >in the works as a new product which should help tune-up all of
> >the oscillators and keyboards in any system.
> >
> >We're planning a revision to the manual soon to include more
> >infoon the power connector, and the trimmers etc, but we've been
> >way busy building Zeroscillators night & day instead!
> >
> >Best Wishes!
> >
> >
> >Cynthia
> >
> >http://www.cyndustries.com/
> >
> >
> >Richard Brewster wrote:
> >
> >
> >
> >>I've discovered my ZO is a little bit off on the 1V/Oct tracking.  It is
> >>more apparent at lower frequencies.  It would be handy if the manual
> >>pointed out the location of the 1V/Oct trimpot.  I haven't tried looking
> >>for it yet, but I will.
> >>
> >>-Richard Brewster
> >>
> >>http://www.pugix.com
> >>
> >>
> >>
> 
> 
> 
> 
> 
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