Inverting and or non inverting amp?

If you can't tell the difference in sound use a CD with vocals , to hear the difference. If you still can't your speakers aren't setup to image correctly. There are lots of threads on speaker setup to help you out. Also the bass will be kinda sucked out, though keep in mind it is a subtle difference.

Not that simple. Almost half of all vinyl and CDs have the absolute polarity inverted. So you really need a polarity inversion switch on one your components (mine is on the DAC). Some of the labels with reverse polarity are RCA, Mercury Living Presence, MCA, Capital, DG, London and some Sony. So a CD with vocals will not help unless you know the polarity of the CD itself.

Thanks guys for all of the responses. I have a test disc from my car audio days and I can now hear the difference with a track specifically used to judge relative polarity and phasing in and out.

Tbg...Tube gain stages invert polarity, but a "cathode follower" (unity gain) which is usually included to provide low output impedance, does not. So your rule should be to count the gain stages.

Yarvis...most test discs deal with "relative polarity" as you call it. This relates to the two channels being in phase with each other, and the out of phase condition is very easy to hear. Absolute polarity, where the two channels are in phase with each other but may both be inverted is much much harder to detect and sometimes impossible. Besides, as Elgordo says, who knows which way is correct?

That's not what elgordo said. Try an old Mercury or maybe a Nat King Cole on Capital and the difference is very apparent.