“I’m getting ready to add an Apogee PSX-100 to my Digi 001 system, which already has a PreSonus Digimax preamp (using the ADAT optical output) and a two channel Neve preamp connected to a pair of analog inputs on the 001. How should I connect all this stuff?”
This is the type of question your Sweetwater Sales Engineer will be able to help you through. In short, you are going to leave your Digimax connected to the 001 as is. You’ll run the Neve into your Apogee converter, and then use the S/PDIF output of that to feed the 001’s S/PDIF input. The 001 can listen to both its ADAT Light Pipe input and S/PDIF at the same time so all you need to do is figure out the clocks. It’s important that the three digital devices all be slaved to the same clock, otherwise you’re likely to have glitches, clicks, and pops in your audio. Fortunately your choice of gear has made this relatively easy to accomplish. We’ll use the Apogee as our master word clock source since it probably has the most stable clock in the setup. Simply run a word clock cable from the PSX-100 to the word clock input on the Digimax. Set the Digimax to slave its clock to the incoming word clock. Meanwhile set your Digi 001 to slave its clock to the digital audio coming in over the S/PDIF port (this is the audio coming from the PSX-100). This will ensure that all three devices get their clock from the Apogee and even though there are two different sources of digital audio they will be in sync. You should be able to leave your setup like this all the time, even when you are playing back and/or mixing material. The Apogee’s clock is good enough that it can make a noticeable difference in your sound all the time.