MOTM

>
> MOTM 300 VCO vs. Moog 901B VCO:
> Note: There is a big difference in functionality between these two!  The
> Moog 901B has a wide range but isn't terribly linear.


The RA Moog tracking is 10 times *worse* than a '300.


 >Mine have recently
> been calibrated and do well over 5 octaves with the 8' octave range
> setting.  This doesn't hold true for the other octave range settings.

That's be cause he had truble finding good capacitors.

 > The
> 901B has no PWM, no Sync, and no linear FM. The output of the MOTM 300 is
> very hot, about twice the level of the 901B.  I'd love to do these same
> tests with some Moog 921 oscillators if I could find some!

That's probably true: the 921Bs I had were about 6V pk-pk.

>
> - Sawtooth Waves: No major difference.  The MOTM might be a tad
> brighter/buzzier but it was really hard to judge.  The mid harmonics might
> be coming out more.

That's the OP-275's fast slew rate. The MOTM has more harmonic content.

>  When mixed together, the beating between these two
> oscillators is *really* intense.  I had them beating about once every 10
> seconds but the sweep caused by the phase interaction was like a very wild
> PWM with a pronounced almost sawtooth modulation.  I could not get this
> kind of beating between like oscillators on the Moog or the MOTM.  There
is
> something really wild happening when combining these different oscillators
> running off different power supplies.


What you are hearing is the Moog not tracking with the '300. It's not the
power supplies.
This is just the difference in *relative* tracking with the Encore as the
"reference".


> - Sine Waves:  Very small difference.  The 901B sine had a few more
> harmonics in it making it sound slightly more nasal than the MOTM.  Both
> seemed to have a few extra harmonics so I might be picking up a tad bit of
> distortion elsewhere in the signal path (VCAs, mixer panels, etc.) but it
> was quite musical.

No argument here.

>
> - Triangle Waves: There was pronounced difference between these waveforms.
> The MOTM had a more "hollow" sound while the Moog seemed to have a
> "rounder" sound.  They are both recognizable as triangle when compared
with
> Saw and Pulse but there is a difference.  I dare say that I think I prefer
> the Moog triangle wave in this case because it sounds a bit "fatter" than
> the MOTM.

Again, the MOTM waveforms are closer to ideal. But again, this is
subjective.


>
> - Pulse Waves:  These are certainly different.  The Moog Pulse Width
> control needs to be set fully to the right to get close to a square wave.
> Even at that it doesn't sound as fully "square" as the MOTM VCO in the
> center of the dial.  There is a tad bit more buzz in the Moog VCO, leading
> me to believe it isn't quite square.  At the narrowest setting (fully left
> on the Moog and fully right on the MOTM), the sounds were very close but
> the Moog had just a bit more nasal quality to it.  The MOTM PW that is
> fully to the left is quite different from any of the Moog PW settings.
> Sweeping the PW on both sounds quite good although the Moog PW is
> equivalent to only the right half of the MOTM PW.  Both are quite good
> sounding!


I never understood Moog's "offset" with PW on the modular. Very strange.

Keep it coming Eric! (and Ben V. can compare as well).

Paul S.