SPDIF seems to be one of the biggest sources of problems (at least the amount of posts search returned using spdif in this forum...)
But I didn't find answer to my problem though.
I have connected a guitar pre-amp using SPDIf. Scope is set to slave and cable is a quality one.
When I play guitar the sound is distorted regardless of output level set in preamp.
distorted sound from spdif input
I had a similar experience with tripleBoard/Luna/Pulsar and a dbx386 stereo tube mic preamp with SPDIF outputs.
The dbx originally worked fine with tripleBoard. Then I upgraded to Luna and the 386 SPDIF didn't work. Then I upgraded to Pulsar and it started working again. Then I upgraded to SFP and it stopped working again.
The 386 worked at 24 bit but not 16 bit output. I finally gave up on the whole thing.
There is something very strange about the SPDIF implementation on Luna/Pulsar. If you figure out a solution, let us know.
The dbx originally worked fine with tripleBoard. Then I upgraded to Luna and the 386 SPDIF didn't work. Then I upgraded to Pulsar and it started working again. Then I upgraded to SFP and it stopped working again.
The 386 worked at 24 bit but not 16 bit output. I finally gave up on the whole thing.
There is something very strange about the SPDIF implementation on Luna/Pulsar. If you figure out a solution, let us know.