There's no section for this, but . . .

it falls under "Operation" so I'll post it here. I have a later model 212-75 with the Phasor built in. The "Phasor" knob is a depth control and the "Rate" knob is a speed control to put this in terms seen on most phase pedals these days. However, the part I don't get is the Rate knob can be pulled out for "Manual Control". What exactly does that do?
Take care,
Smitty

The Rate control position normally sets the speed at which the phasing filters are swept. By pulling out the Rate knob, you disable the automatic sweep and the control now allows you to define any point within the sweep manually and LEAVE it there.
Since the tonality of the audio signal is different at every point in the sweep, you can find a static point in the sweep that gives you a tone you like.
This is a little like using a Wah-Wah as a tone control by finding a "sweet spot" and leaving it there.
The effect will change in intensity with adjustments of the Phasor (depth) control. In the manual mode you can use the Phasor circuits in a way similar to that of a specialized audio filter.