Problem with DAC

[iReally]

I just got a Super Pro DAC707 and I can't get it to work. The signal path is:
iTunes --> MacBook optical out --> Super Pro --> cMoy --> Grados.

The optical out on my MacBook seems to be working fine, I have used it before and it worked. When I plug in the optical cable it cancels out the regular volume control, so I am sure the MacBook is recognizing the optical cable.

The cMoy is the jSeaber BassBoost edition available on eBay, it works great, I've never had any problems with it.

I don't know whats up. I'm pretty sure everything is set up right....

The output from the Super Pro is left and right RCA. I have a cable that is L/R RCA to a single 3.5mm that I am plugging into my cMoy.

Any suggestions will be most appreciated!!!

Thanks,

Ian

P.S. I'm thinking that the DAC is a dud... I just want to make sure everything is set up right and there are no compatibility issues that I'm over looking before I call and say the unit doesn't work.

[Herandu]

I don't own a MAC,so I don't know what the sound output settings are for the digital output. However, check to see if there is any mention made of PCM amongst any other format such midi, etc. The DAC needs a PCM formatted digital input stream in order to give out analogue audio.