External HD Changing the quality of the sound?

I too use iTunes. But the Mac version is better integrated with the OS from what I understand than the PC version and it is a great way to organize album meta data and playlist. I just organize them once and it works for my music servers and iOS/iPod devices as well.

To use memory play, try BitPerfect from the AppStore. It's a very simple, very easy to use plug in to iTunes. It bypasses iTunes' playback engine and sounds very good.

It's IMHO a close second to Audirvana Plus (which is still affordable) and A+ provides the option to play DSD files as well, if supported by the DAC (it will convert DSD to PCM otherwise). If you only have primarily RBCD or HR PCM, BitPerfect will work just as well.

PureMusic and Amarra IMHO are much pricier and not worth the added moolah.

so BitPerfect auto-select the memory cash?

cache* sorry

Yeap. BitPerfect (click on the little logo on the top right of the menu bar. Select Preferences. You can adjust the size of the cache obviously limited by the RAM installed but RAM is cheap these days. Our old 2011 iMac already had 4x4GB RAM

Doggiehowser - I am just doing some pre-lim exploration of computer audio...and, in another thread, noted your enthusiasm for a set up that sounds somewhat like mine. Hope you can provide additional insight and guidance here about use of Bitperfect.

If I purchase Bitperfect do I need to install it on my external hard drive where my iTunes music library (and iTunes) resides or will it work properly with iTunes (which is operating from the external hard drive) if BitPerfect is simply downloaded to the MacBook Air hard drive? Hope that is not too ignorant a question.

System is: iTunes & Apple Lossless Files on SeaGate 1TB ext. H/D>>MB Air>> USB out>>M/F V-Link>>M/F DAC>>Pre-amp.

Thanks in advance for your help.