Hi guys.... I'm an electronics recycler that works for an IT company that has been implementing apple-based setups since the early 90's...
I built a largely analog studio myself and I'm fairly electronically inclined. I'm pretty sick of using my duet (it's insanely buggy, I have to do pr-ram resets constantly, maestro is the worst and shittiest piece of software to have, it's too light weight and people knock it off the table constantly, and the spaghetti breakout cable is super low quality and I have it re-soldered and cobbled together as it is) and want to take my Mac Pro 4,1 home and throw a nice GPU in it.
What I basically need is a 2+ input (I wouldn't hate more) balanced input interface with sweet ADC's and the ability to bypass preamps.. I feel like there MUST be some older options that were world class at the time, but are cheap as hell now...
I have a bunch of older computers that I've gotten up and running:
1. Mac IIfx, 32 mb ram, 250 gb HDD + ethernet card
2. iMac G4 1.25 Ghz
3. Mac Mini... forget the specs inside, but I think this is the most powerful G4 I have...
4. PowerBook G4 6,2 w/ 1.25 gb ram (I installed OS 9.2 on this and the GPU (GeForce 5200) didn't work too well
5. G4 Cube
And of course, I have the cheese-grater modern 4,1 that is relatively maxed out for audio purposes as it is.
I also have a comically maxed out windows 98 machine that I never use. I literally save this stuff from getting melted down at the yard all the time.
I'm not really sure where to start or what the best option or OS is for this purpose. I have absolutely no problem doing something wacky and I'm mostly doing this because I think it would be hilarious if it worked just as well as what I have, so the more "outdated" I can go the better as far as fun factor is concerned. We mostly use tape so it's not critical that the interface/setup is bug free, especially after dealing with the Duet in High Sierra for the past 3 years.
I just have no idea where to start when sifting through all the nubus and PCi hardware and how all the old software runs.