phaser w/ transformers IDEA???!?

[doug deeper]

does anyone know if this has been done? (using transformers for the phase spliter sections)
any idea of the benefits/drawbacks?
just an idea!   

[Sir H C]

Schaller Rotosound did it.

[doug deeper]

ahhhh,
i figured it had been done, do you have one of these? (or used one)
if so, how does it sound? hmmmmm?

[Bore-inger]

ssounds splitey but the fyrst answers wrong

[doug deeper]

ssounds splitey but the fyrst answers wrong

wha?

[Sir H C]

I would assume that he means that it is listed as more of a leslie effect than a phaser per se?  They used transformers where the secondary winding would change the inductance by running a modulated current (IIRC).  Never had one, always outbid on the bay...

[R.G.]

Transformers have been used as phase splitters before, of course. I don't know whether they've been used in phasers.

The essence of a phaser is a phase splitter driving two paths, a fixed shift path (resistor) and a variable shift path (R-C); all that followed by an adder to combine the two paths. These stages can be seen separately in the Univibe, where the first transistor of each phase stage pair is an adder, the second transistor is a phase splitter.

The classical opamp phaser uses an opamp's differential input to fake the phase splitter by subtracting the fixed path from the variable path. The output can then just drive both fixed and variable paths with the same signal.

A transformer phase splitter needs a driver for each transformer. Economy in design would make the driver be the same as the adder. You could do this with a darlington device as both a high impedance adder and a transformer driver.

However, this is replacing half of a $0.50 opamp with a $3.00 transformer if you can use the cheapy Xicon transformers at Mouser.

[doug deeper]

yeah the price is a bit different, but i just scored a lot of small transformers for 30 cents each!

[R.G.]

You're in the groove! Go for it.

[doug deeper]

any predictions on what the sound differences will be?