From an analog purist perspective, you leave tracks on analog to the last possible step to avoid processing in the digital realm. When we speak of processing we are primarily concerned with digital conversion – from a higher to lower bit depth and/or rate, and visa versa. For example, transferring from analog to 24/96 and then converting that digitally to 16/44 for CD is less desirable than going right from analog to 16/44.
A lot of other things commonly happen in the digital realm as well, such as the disparity between input, internal processing, and output rates, which just adds another conversion step or two. The truncation and dithering schemes, depending on your particular device, leave a lot to be desired.
Plug-ins, emulators, digital compression (God forbid) and such add another layer of potential corruption to the original audio that you took so much care to record in analog. These tools are convenient – part of the draw of digital, but can be destructive to the original analog sound.
Supplementing analog with digital, whether with ADAT, Pro Tools, or whatever, is a great use of digital. But here, the two are synced and stay in their respective formats for the duration.
I’ve used synchronization in recording since pre-MIDI (1984), first with Proprietary Roland sync on their synths and drum machines and later with MIDI. This was the original Hybrid studio – analog tracks with virtual sequencer tracks. You can do the same thing with digital recording, either slaving the DAW (or what have you) to the analog machine or visa versa, if the analog machine can slave to sync.
I would rather slave a comparatively inexpensive Alesis XT or something with its relatively inexpensive SVHS tape to my analog machine, than fumble with a second analog machine. If it came to that though I would just upgrade to an analog deck with more tracks. But I don’t have to do either, since I have more virtual tracks on my sequencer than I can use, plus separate drum machines that slave to that. And those virtual tracks go directly to my half-track master, first generation. It doesn’t get any cleaner than that.
~Tim