[sdiy] "Living VCOs" PCB in 2009 ?

[Ken Elhardt]

This was several years ago and spanned the The-Gas-Station and
Analogue Heaven lists.  It started out with people claiming the Moog
VCO was real magical and nothing else on earth sounded anything like
it.  You know, the usual B.S. that fills these lists.  After getting
actual Moog wav files from a couple of different people it turned out
there was nothing special about it at all.  It's waveforms looked and
sounded like others, it had LESS jitter than other oscillators, and
drift could be easily programmed, and all kinds of other VCO's were
tested and compared too and files were put online to put to rest some
of the ridiculous things people said about them.  I posted cycle to
cycle jitter measurements too.  Most of those files are no longer
online except the very last one I posted which compared that supposed
super magical Moog 901 VCO with a miserable digital waveform generated
in Cool Edit Pro and there is virtually no audible difference.  The
wav file below alternates between the Moog and a digital waveform a
few times over the length of the file.  Jitter measurements comparing
the Moog and a modern Technosaurus VCO are after my text and it can be
seen that the Moog has about 3 times less.

http://home.att.net/~elhardt2/Sawtooths.wav

Now if somebody is designing a new unstable VCO, that's fine, if
that's what is meant by "living".  If I want unstable, I use my
Doepfers.  But nobody should be claiming that the Moog VCO is somehow
different/better than other VCO's.  There just isn't anything there to
back that up.

One of the many hypothetical potential products that I'd like to come
out with is called the Acoustic Oscillator and produces "alive" and
constantly changing waveforms the same way acoustic instruments do.
Prototyping the thing up in Reaktor has been on my list for a couple
of years now.

------
Moog Modular 901 VCO 65Hz, 40 cycles measured.
Cycle to cycle jitter in microseconds.

+1.4  -0.7  -0.7  0.0  +2.1  -0.7  -0.7  0.0
+0.7  +0.7  0.0  +2.8  -2.1  -0.7  +1.4  0.0
0.0  0.0  0.0  -0.7  0.0  +0.7  -0.7  +0.7
0.0  -1.4  +1.4  +7.0  -1.4  0.0  0.0  -1.4
+0.7  0.0  +0.7  0.0  0.0  0.0  -0.7


Technosaurus Selector VCO 65Hz, 20 cycles measured.
Cycle to cycle jitter in microseconds.

-2.1  +3.5  -4.9  +3.5  -2.1  -3.5  +2.1  +0.7
0.0  +1.4  -2.1  -2.1  +3.5  +2.8  -6.3  +4.2
+1.4  -2.1  -2.1
------

On Tue, Dec 9, 2008 at 8:41 AM, Antti Huovilainen <ajhuovil at cc.hut.fi> wrote:
> On Tue, 9 Dec 2008, Ian Fritz wrote:
>
>> Ken did a superb, thorough study of this.  It's really depressing that
>> nobody seems to believe his results.
>
> I seem to have missed this. Can someone post a url to the results? (Which of
> course include detailed explanations of the tests, right? (*))
>
> Antti
>
> "No boom today. Boom tomorrow. There's always a boom tomorrow"
>  -- Lt. Cmdr. Ivanova
>
> *: Any study which only says "Here are the results, but we're not telling
> you exactly how we got them" is largely useless.
>