There are a couple of ways. If you have a cdp or dac with a polarity switch, set it to 180. If the amplifier has a polarity switch, leave it at zero. Wire the speakers normally for each channel - amp black to speaker black, amp red to speaker red.
If the preamp is the only polarity inverter in the chain, then reverse the speaker wires for each channel. Left channel: amp red to speaker black; amp black to speaker red. Right channel: same thing (important!).
A good way to keep track is by adding and subtracting: add one for each piece that inverts and zero for each piece that doesn't. If the result is zero or even, wire the speakers normally. If the result is odd, reverse the speaker wires or flip ONE polarity switch to 180.
In all cases, the interconnects are normal - left/left right/right.
If the preamp is the only polarity inverter in the chain, then reverse the speaker wires for each channel. Left channel: amp red to speaker black; amp black to speaker red. Right channel: same thing (important!).
A good way to keep track is by adding and subtracting: add one for each piece that inverts and zero for each piece that doesn't. If the result is zero or even, wire the speakers normally. If the result is odd, reverse the speaker wires or flip ONE polarity switch to 180.
In all cases, the interconnects are normal - left/left right/right.