It's not really a thing designed to add second order harmonic. It's a pot that balances the VAS. When the VAS is out of balance one way or the other it produces negative or positive phase second harmonic distortion. P3 in the F5 does the exact same thing, except with the F5 you're putting DC on the outputs when you turn it so you need to adjust it along with P1 and P2.
That kind of adjustment makes a big difference. After having experimented with it quite a bit, I think Pass is dead right on his theories about distortion. If you want deep, enveloping, layered imaging, you want some negative phase 2nd order distortion.
That kind of adjustment makes a big difference. After having experimented with it quite a bit, I think Pass is dead right on his theories about distortion. If you want deep, enveloping, layered imaging, you want some negative phase 2nd order distortion.