SynthModules

> Quality? Let's look at signal-to-noise. According to the 
Synthsizers.com
> FAQ, the dotcom VCA has "a signal to noise ratio of 82db (CD 
quality is
> around 96db)." The MOTM-190 has a dynamic range of "better 
than 100dB."
> That's a very big difference.

It might be useful to note that signal to noise ratio is different 
than the noise floor. The noise floor is the actual hiss (thermal 
noise).

Signal to noise ratio is the ratio between the test sine signal 
peak and the next lowest signal peak. This is usually the second 
harmonic distortion. A second harmonic distortion of -82 dB is 
approx. a THD of 0.005% or as good as virtually all audiophile 
hi-fi gear.

Analog to digital converters have a noise floor fixed by the math 
of 6 dB per bit (hence 96 dB for 16 bit).

Based on my measurements at Wiard, the noise floor of a TL074 
is about equal to the self noise of a 24 bit converter. An LM837 is 
about -15 dB below the same 24 bit converter. But the signal to 
noise ratio is -60 dB or so because the THD is 0.02% (second 
harmonic at -60 dB). This is plenty good enough for prime time!

The major source of hiss noise will come from the A to D inputs 
of the digital compositing system you use, rather than the analog 
equipment.