I recently decided I wanted to connect my Kemper via SPDIF to my Apollo twin so that I can have it in stereo without losing two of the analog preamps. I purchased the necessary cables, and a coax to opt converter.
The Apollo twin will not slave to the kemper no matter what I do - I've changed the sample rates, etc. I've changed the mode to "internal" on the kemper output page, etc.
However, if I leave the Apollo twin as master, I can get audio from the kemper. This audio is digitally distorted with crackles, etc. I found that if I put the Kemper sample rate at 88.2 or ABOVE, and turn the Sample Rate Conversion on my Apollo, I get a perfect and usable sound. However, there is a very slight latency - I measured it by recording both the digital in and the analog in at once. Unfortunately, this latency is just enough to make it unusable in this mode to me.
I've taken a look at the Kemper manual and there is a mention that in order to use the Kemper as a slave, there needs to be clock sent back into the Kemper via the SPDIF input. However, this is not possible with my audio interface. The Apollo twin has no way to send clock out in this manner.
So I'm wondering if anybody has any ideas of how I can get the SPDIF working with the Apollo without the latency? I think if I were able to use the Kemper as the master clock, it may help. Engaging the SRC on the Apollo may have something to do with the latency, but I'm not sure.
EDIT: As a note, my Apollo twin is set to 48kHz. I've tried switching it to 44.1 and it doesn't help.