Inverting and or non inverting amp?

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.

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