Doepfer

> Can someone give me an example of an application that requires
> a perfect sine wave? Will a perfect sine do special things when
> used as an FM or AM source? I don't think there are too many
> people doing additive synthesis, but I can see how it would
> benefit from perfect sines.

In DX7-style FM synthesis perfect sine waves are important. I once 
used a softsynth, where second order parabolic functions were used as 
approximations for sine. The results were not satisfying, until the 
issue was fixed by using higher (up to 8th) order parabolic functions.

Maybe ring modulation and frequency shifting benefit from pure sine 
too.

My Cwejman VCO-6 and VCO-2RM make good sine waves by analog 
standards. They look perfect in my oscilloscope. However, one can 
hear, that VCO-6 has some "buzzy" higher harmonics present. It is not 
immediately noticable though. On the other hand, VCO-2RM draws 
attention to more pleasant lower harmonics. I would say VCO-6 is 
closer to perfect sine.
 
Z3000 sine certainly doesn't look perfect. If people like it, I would 
guess it is not too buzzy.

Skewed sine is is different from triangle or filtered saw and can 
sound like a vintage Theremin. It should get progressively more 
skewed (brighter) at lower frequencies though.