I built a second Phase 45 the other day and stumbled on a mod you might want to try. Layout and schematic at Tonepad.
If you put a capacitor from the wiper of the speed pot to the opposite side of the 3M9 resistor that goes to the speed pot (i.e. to where the 3M9 resistor joins the 3 470k resistors) it changes the shape of the LFO to something resembling a square wave.
I experimented with capacitors from as high as 10 uF to as low as 0.002 uF and ended up using a spdt centre-off switch to choose between 1 uF, 0.005 uF and no cap. Bigger caps give a more severe effect.
It's more effective at medium to fast speeds.
FWIW I also added switchable phase caps, a vibrato switch, and a 20k trimpot in place of the 10k dry mixing resistor to dial in the most intense phase sound I could get.
Some of those sound like cool ideas- I'll have to implement one or 2 to the one I just finished.
Thanks!
Audioguy