VC Phaser using the LM13600

[jorgen.bergfors at idg.se]

>Hello,
>The phase versus frequency function for a typical single RC all-pass
>filter is given by

> phase(degrees) = -2*arctan(2*pi*f*RC) for a lagging type filter and

>phase(degrees)= -180-2*arctan(2*pi*f*RC) for a leading type filter.

Well, I suppose my question should have been: Which of the commercial phasers use lagging and which use leading filters? Can the Hammond scanning vibrato be considered leading or lagging?

I suppose my phaser (and the Small Stone) would be of the leading type, as the frequency shift gets lower at higher frequencies (if f=0 then phase is -180 degrees). But if you look at the oscilloscope, the signal moves left when the phase shift is increased. Because the oscilloscope trace moves from left to right, it must mean the signal is delayed and therefore lagging! Right?

/Jorgen