After 18 years using Windows I, for technical reasons,switched to Mac just in time for the update to Yosemite to totally obviate a three thousand dollar investent in music production. Now my studio is off line, silent aND useless. Starting to miss Windows...
Such situations are well known in the industry. I used to have an oscilloscope that ran on Windows 98; and I used an UV EEPROM programmer that ran under control of MS DOS. I suggest that you look into ways to reanimate your hardware. Pretty much every OS can be ran today, with their native drivers. If it takes a separate PC to operate your studio, a PC today is far cheaper than $3K of probably less than common music equipment.
What? Old software won’t work on Yosemite, or what?