I have a Catalinbread Dirty Little Secret that I want to try at 18 volts. I'm told they sound great that way. Rather than tie up two outputs from my PP2+, I was thinking of building a Road Rage to stick between a normal 9-volt supply and the DLS.
I see the 15-volt output from the Road Rage uses its own regulator. However, I want to run it at 18 volts, without the extra regulator. Is the 18-volt output from the charge pump sufficiently regulated that it will power a dirt box cleanly?
15V is still worth trying. I suspect 18V unregulated will be noisier, but not hugely so.