Hello redxpanda,
Welcome to AAC.
We generally like for our new posters to stay with low voltages. 680VDC is a dangerous voltage level. It doesn't take much current to kill a person at that voltage.
What are you doing with this power source?
What is the power source itself? Did you build it? Do you have a schematic of it?
Thanks for the warning, I know that it doesn't take much to kill a person at high voltages. The power source is a driver for cold cathodes, and I wanted to replace it with leds instead of the cathodes, thats why I need the 20-24mA. I did not build it and I don't have a schematic of it sorry.
Well I already have this power source and it is sound reactive and I don't want to go through the trouble to make one the same but with lower volts and higher amps. I just want to get more mA out of this power source.
That would require a complete re-engineering of the existing supply, as the components would not be rated for 3x-4x the design current at that voltage.
Does the sound source supply power to the CFL inverter? If so, you may be able to simply remove the inverter and, by use of some current limiting resistors for your LEDs, use the sound source directly.
IF, and again this is a big IF, the CFL inverter is being driven by the audio signal, you should be able to to use what is now the input to the CFL inverter to drive your LEDs. Do you have a scope? Can you verify that the input to the inverter is indeed audio or audio riding on top of a DC level?