Parasound says no drivers are necessary for Mac OS platforms. The Halo’s instructions say it’s just plug and play.
So a few things to mention:
1. I don’t know anything about DACs. Totally clueless, so I really do appreciate everyone’s insights and help.
2. I’m playing iTunes from my Mac. Most songs have an output sample size of 16 bit and a sample rate of 44.1kHz
3. When I plug my headphones directly to my Mac, the Mac says it’s playing the songs at 16 bit/44.1kHz, matching the music’s size/rate.
4. When I plug a portable FiiO DAC/headphone amp into the Mac’s USB, the FiiO’s screen says 24 bit/96kHz, though the Mac automatically says the FiiO is playing something slightly different: 32 bit/96kHz.
5. The Parasound has no screen, so when I plug it in, I don’t know what it’s doing. I do know that when I select among the Mac’s dropdown menu of formats, there’s now a bunch of choices: 44.1K all the way to 705.6kHz (each with 16, 24, 32 bit choices). When I choose the higher rates, like 705.6 or 384, I get the fizz). When I choose the lower rates, like 44.1 all the way to 96kHZ, I get less fizz, usually none.
6. The Parasound’s spec sheet says it supports DAC sampling rates "up to 384 kHz / 32-bit PCM.
7. When I say the Parasound doesn’t lock, what I really mean is that it doesn’t automatically pick a sample rate to accommodate the Mac (the way the FiiO does). When I first connected the Mac to the Parasound, I got tons of fizz. Now that I’ve followed Erik’s great advice about adjusting the Mac’s output rate, I get much less fizz. But when I do pick a good (i.e., non-fizzy) output rate, the Mac definitely stays on that rate.
So my two questions:
A. Should I expect the Parasound’s DAC to automatically find the ideal rate from the Mac? Or should it just allow me to choose (either wisely or poorly) like it’s currently doing? (I’ll exchange this Halo unit if I need to, but I won’t if I don’t.)
B. Assuming that I’m just supposed to choose the ideal output rate, what is that ideal rate? Should I set the output rate to match the iTunes songs’ rate of 16/44.1?
Many thanks to you guys. I’m new to this forum, and I already feel indebted to it.