preamp inverts polarity


I have a DeHavilland Ultraverve 3 preamp that inverts polarity.
my problem is my speaker cables, the negative cable is designed for negative terminal connection as is the positive cable is designed for positive terminal connection, so reversing the speaker cables defeats the design of the speaker cables.

what am I to do ?
mboldda1
Of course it’s only fair to point out that phase coherence is a different animal than Absolute Polarity.
Since Geoff reported my post because "blah blah blah" hurt his feeling, I'll repeat my point. Phase coherence was an 80's fad that made bold promises and generally didn't deliver. It doesn't seem to be as important as it's been sold to be. 
Huh? Why would I report your posts, Costco? They are often the high point of my day. My substitute for the funny papers, if you will. 
@mboldda1 

Just insert a dedicated stereo signal phase inverter between your preamp and power amp if switching the leads on your speaker cables fails to restore the polarity.