You can by using a custom cable to combine both high power 9vdc outlets into a single 18vdc outlet.

It’ll work with the PP2+ if you have the right cable.

I meant PP2+ (Pedal power supply 2+)

No.

Yeah, you need a voltage doubling cable. Just make sure you get the polarity correct. Voodoo Labs makes normal and reverse polarity doubler cables: http://www.voodoolab.com/cables.htm

Check your POG’s wall-wart. There should be a diagram showing the polarity:

Normal Polarity:

Reverse Polarity (center positive):

Make sure you have outputs 1 + 2 switched to 9v and not 12v and try it. If the POG does not function correctly, then there is too little current, and you should try outputs4 and 5, both on their default 9v modes. (outputs 1-4 and 7-8 give 100ma each, outputs 5 and 6 give 250ma each at 9v when set to the default 9v setting)

I did a quick google and I think that 200ma at 18v should be fine.