Correct Way to Invert Phase

Yogiboy is correct. Rewiring the preamp-to-amp cables such that + is connected to - and vice versa would connect the signals on the preamp’s + outputs (the RCA center pins) to the amp’s ground, which of course would not work too well :-)

If the preamp-to-amp connections were balanced (which I presume they are not, since you are using a CJ preamp) interchanging the connections to XLR pins 2 and 3 at one end of the cables would do the trick.

Also, if by any chance your speakers are not passive (e.g., if they incorporate powered woofers or are otherwise AC powered, or if the amp outputs are connected to powered subs), I would check with the speaker or sub manufacturer to be sure it is safe to connect the amp’s + outputs to the speaker or sub’s - inputs, which conceivably could be connected to ground via some low impedance within the speaker or sub.

Regards,
-- Al

Sounds a little obsessive-compulsive, but it would bother me too - probably enough to make a change.

Play Hendrix and try to fix the phase inversion.
That will make you crazy. Intentional phase inversion was one of his tools for mixing a recording.

Some recordings sound better one way. Some sound better the other. If you notice a big enough difference then you could try switching for every recording and write down which way sounds best, then switch every recording. Or plan your listening by grouping tracks that sound best in phase and playing them back to back. But I found this to be too hard. So what I do now, split the difference. Wire one speaker each way.

Incoming.....!