My AP+PP finally arrived (all the way from a fellow headfier in Vietnam).
I listened to alot of music last night. IMO the AP+PP into input 1 is better than the USB32 or the other spdif inputs. The AP on any other input other than #1 equals the USB32 but of course in this scenario the AP is at a disadvantage. The AP on input 1 seems to sharpen the focus of everything. There are no real tonal differences between the AP and USB32, everything is just less fuzzy and warm with the AP.
I listened to a wide variety of music, many different genres with widely varying audio quality. With high quality/highly dynamic source recordings I heard very little difference between the AP and the USB32. So for those of us who only listen to highly dynamic recordings like Eva Cassidy and Chuck Brown's "The Other Side" http://www.dr.loudness-war.info/details.php?id=3559 or Muddy Waters' "Folk Singer" http://www.dr.loudness-war.info/details.php?id=20945 don't bother trying to do better than the USB32 unless you can hear the proposed replacement for free before deciding. I'm not quite sure why this is the case but great recordings can often make lesser equipment sound great and anyone who has been to a commercial audio show where exhibitors refuse to play anything other than awesomely recorded classical music probably already knew that. This may be what is going on with the USB32.
If you have had a chance to compare two different versions of the same album say the mediocre cd version of Wayne Shorter's "Speak No Evil (rvg edition)" and the highly dynamic HD Tracks version, the main thing you will hear is a difference in soundstage depth. I'm convinced that soundstage depth in recordings is dependent on that recording's dynamic range. The low volume details and cues are drowned out on low dynamic range recordings which make the music sound as if it is more forward or flatter while highly dynamic recordings provide depth and space. I am a Dr Database nut and so far my little observation has held up each time I compare different versions of recordings.
So difference wise, the rubber met the road when I listened to less dynamic and average to terribly recorded source material. Input 1 with the AP does wonders here and the differences are immediately apparent. The AP on input 1 has this awesome ability to somewhat draw out those low volume details and music cues that give stereo music the illusion of soundstage depth on very bad recordings. A comparison of the terribly mastered Adele's "21" http://www.dr.loudness-war.info/details.php?id=7674 which may be the worst recording I own. It was no contest, the AP offered a deeper listen and details are sharpened without becoming overbearing. "21" does not become great or even good but it is substantially better via input 1. Its not that the USB32 is less detailed its just that its warmer sound hurts its ability when it comes to soundstage depth on these types of recordings. The improvement is significant, the AP on input 1 is not adding any color it just seems to handle compressed music better.
The bummer here is that I am not sure if I am comparing the AP to the USB32 or if I am comparing the BNC input to the USB32. My cd player when used as a transport on input #1 is better than the USB32 but not as good as the AP. I have a old audio gd DI-V3 that I may try on the BNC input in order to compare it to the internal USB32. I suspect that I fried my DI-V3's firmware though so don't hold your breath waiting for that comparison.
Too bad there isn't a I2S version of the AP.
Edited by ciphercomplete - 11/24/13 at 8:52am