Adding transformer isolation to a stereo panning pedal

[rollo greb]

Hi, I am trying to build a pedal that will allow me to pan between two amps, like this schematic:



However, I would like to add transformer isolation to prevent hum and I've just started doing some reading to understand this. I came across a couple schematics from geofex:

http://www.geofex.com/FX_images/spltr2.gif
http://geofex.com/FX_images/humfree2.gif

I would like to use the same mouser transformer since it is cheap and I can get it from small bear with the rest of the parts I need. As the panner schematic I have already has buffered outputs, would it be reasonable to just add the transformers into the signal path? Would the buffer be enough to drive the transformer? Thanks for any help, I'm kind of figuring this out as I go.

[R.G.]

It'll probably be fine. Notice that if you use a single 9V power supply, you must DC-isolate the transformer with capacitors as in the first link. The second link uses a bipolar supply to ensure zero DC across the transformer, which is a necessity.

[rollo greb]

Ah yes thanks, I didn't notice that. I'll probably just use coupling capacitors then to avoid requiring -9V.

If I were to use a bipolar supply with my panning schematic, I'm guessing I could just change the Vref points to ground, and the ground points to -9V (with the exception of the pulldown resistors)? This would give more headroom?