"Vibrating" a power supply?

[LinuxMan]

Hello...

Was just thinking about doing something that records and playbacks the
guitar signal (like the zvex lo-fi junky).

The vibrato feature sounded easy to implements. Just "shake" the power
supply I heard.

Now, I don't know how could one do that. I was thinking something in
these lines:

From Geofex, The technology of phase shifters and flangers

Where variable R = jfet.

Am I on the right track there?

For the other parts, just slap a compressor (Orange Squeezer) in front of
the recording path and a booster (Mosfet) at the end and that's it.

Or are there any simpler compressors avaliable?

Thanks
LM