@big_greg "Don’t know about your unit, but my LS100 MW preamp had the phase inverted by design. Reverse polarity on speaker cables as suggested."
I have the same preamp and was never told this.
Aside from the LS100 I also have the KWA100SE, the speaker posts clearly indicate with red and black the connections not sure why the KWA150SE would be any different. Both units were purchased in 2011