[manman]

Just recently ran some mixes through P38 "Edward" regular blue face.

Few good impressions:

Pros:

1. adds slight sheen on upper-mids and glues mix a bit
2. fixes dynamics of mix in very uniform and controlled way
3. makes mixed louder without destroying quality etc
4. very clean sounding, but it does have some sort of opto-color

Cons:

1. input&output knob changes balance of L&R ( or cheap dented switches)
2. Different amount of compression changes L&R balance very annoying (has something to do to M/S)
3. if you sweep with sine-wave, you'll get random harmonic distortion at low levels which is probably destructive to mix

Conclusion: I think for mastering use it needs to be little higher quality build, knobs need to be detented and have no errors in L&R balance because it can seriously damage mix even by 1-2 db of inbalance

otherwise transformer input, opto -color is indeed interesting & sometimes useful for mastering