If something was added, a switch or a relay for example, to short the output to ground at start up one would be protected. A long time ago I tried out the original foreplay with a solid state amp. Being ingnorant I was doing quick AB swaps between preamps. The solid state amp didn't mind but I did blow speaker fuses and didn't know why at the time:)Given that the new foreplay has dual secondaries I don't understand why they decided to parallel them, use a voltage doubler to create a raw 300VDC B+, and then CR filter it down to a OD3 150vdc regulated supply. Seems to me having more voltage to work with would be a plus....especially when direct coupling....heck maybe even a bi-polar supply for a big tail resistor in the CF.
Russ