Yes I have.
I send a full scale 0db (full blast line level) steady tone to one when my digital audio workstation in in record mode so as to alert the clients via an "ON AIR" light that they had better straighten up and play right.
Anyway, I had to mod mine to make it respond to such a feeble signal as a 0db line level input. That is no where near the 6 - 9 volts the power flash is calibrated to respond to.
Here is the schematic:
http://www.nysaes.cornell.edu/cc/staff/pool/homeauto/pf284.htmlWhat I did was remove the 33k resistor you see there.
While this allowed me to drive it with line level audio, it was unstable and a 100k resistor across the screw terminals terminated the drive enough to make it stable.
For whatever reason however, I cannot get a new PSC01 style powerflash to work with this mod, but the old PF284 (brown ones) work great this way.
A problem you will have is that every time there is a quiet section of audio such as even the space between speech phrases, the power flash will go off. And that will be the end of that.
You might be able to store the audio in a big capacitor and drive the PF with that output, thereby holding up the voltage for oh, 10 minutes or so. But that would require pre buffering the drive to the cap so that it doesn't drop your desired audible audio to filtered nothingness.
Any like 1000uf cap from Rat Shack might be something to start with.
Best o' luck.
:Ron