Analog Summing; problems with recording back into Pro Tools. Clocking issue?

[jimbojimbo]

Hi guys,

I've just started doing some analog summing and have been experiencing problems when bouncing the summed audio back into Pro Tools.
The session is running absolutely fine but when I record it back into PT and listen back to that track, there are clicks and pops all over the place!

Here is my setup:

Mac Pro, Pro Tools 11.
Apogee Ensemble running it's 8 analog outs, then from the ADAT output, I'm running it into an RME Fireface 400, which is converting that out to it's 6 analog outputs.
It all runs into an Audient Sumo and records back into Pro Tools into the Apogee Ensemble.

Any thoughts?

Could it be a clocking issue? I'm clocking via ADAT.

Any thoughts would be super helpful!

Cheers,
James