I'm a composition student at Cal State Northridge and I'm just getting involved in starting to record my compositions, so I have some questions.
But, I am an experienced audiophile with way the hell too much *Playback* equipment. Also I worked for a while as a programmer and have a degree in electrical engineering. So I know a lot about the technical aspects of digital, formats, some stuff about analog, etc.
I want to have a mobile laptop-based recording setup. I already have an M-Audio Fast Track Pro. It's not high-enough quality for me as an A/D, but it has a S/PDIF input, so I could get another higher quality portable A/D unit with S/PDIF output and send it to my laptop via the M-Audio.
I'm interested in the Apogee Mini-Me, for one.
As far as getting this stuff to work, I think I have the technical know-how, but I have some questions about jitter and digital performance.
First let me say that I have had good success with my playback equipment by using a battery for low-power circuits (such as the DAC) rather than power from the wall. Battery power is much cleaner. I also use a set of parallel capacitors to provide for instantaneous current delivery on transients.
So I want to do something similar with my portable setup.
For the M-Audio Fast Track Pro, I have already tested it like this: I cut the red line in the USB cable to cut the dirty power from the computer, and power it from its 9V input instead (using a 9V battery, or I can also use a 9V linear regulated supply). It works fine.
To consider the Apogee Mini-Me, it can run from a range of inputs from something like 7V to 16V. I already have this nice 12V SLA battery (with the capacitors) so I can use that to power the Mini-Me.
The only connection between the Mini-Me and the Fast Track Pro will be a digital coax (RCA) cable.
Okay, so my question is: is the jitter behavior primary determined by the accuracy of the clock in the Mini-Me? In other words, does the (rather cheap) Fast Track Pro have no influence on the jitter that affects the A/D process, and does it merely have to transcribe the bits?