Ok, so this evening after work, I popped down to Tottenham Court Road and got myself a 6.5th Gen 160gb iPod Classic. The date on the box was 15th March 2010, so no doubt at all of its provenance.
I got home and installed it, and put a few tracks on it that I knew really well.
As I've aldready got a 6th Gen 120gb iPod Classic (that was bought in early 2009), , it was easy enough to place it next to the new iPod, set the volume to the same level, making sure there was no EQ on it and that the volume limit level in settings was set to maximum. Then using my Audio Technica ATH-CK10 iems through the headphone out port, I did an A/B test.
Yep, the new Classic definitely sounds different, and in a good way. I'm rubbish at describing what I hear - at least in the kind of audiophile terms banded around on sites like this - but I know what I like and I tell you what, I like the sound signature of the new Classic more than the previous version. It's richer, warmer, creamier and more luxuriant in every sense - the bass and drums sound heavier and more resonant, vocals seem more real and human, the slightly hard edges of the 6th gen seem more rounded without losing detail, and the soundstage seems more 3 dimensional.
Don't get me wrong, we're not talking seismic continental plates shifting here, more a degree of deepening and enriching of the whole musical landscape in a way that renders it more enjoyable, more emotional, more 'silly grin on face' than it was before. Truth be told, it rendered the whole experiment of moving between the players a bit of a struggle, given that I just wanted to sit there and soak up this lovely sounding noise.
I dig it baby. Yeah. Makes me glad I forked out the cash now - I needed the extra hard disk space anyway, but this takes the sting completely out of the bite my credit card's just received. Good stuff.
Your mileage may vary, of course, but it does seem at least a few of us are driving the same vehicle.
Oh, and I've just tried the line out, via my Headsix amp, and it doesnt seem to be any different than the 120gb Classic in SQ, but thats only from a cursory listen. Perhaps, as the OP suggested, only the HP has seen a noticeable change? Interesting.