RCA Out To AES/EBU In To DAC

Wrong pinout. You need a RCA to AES/EBU digital cable.

I appreciate the previous posts. Specificallly, the DAC is the EMM Labs DAC 6, and the digital source is the Squeezebox 3. I could not find any discussion in the EMM Labs manual about this issue. The EMM Labs does have a BNC input connector, but as far as I could determine, this is used for feding an external clock signal to the DAC. Can anyone enlighten me further concerning the DAC 6?
Thanks,
Dennis

AES/EBU works at 110 ohms, S/PDIF works at 75 ohms. The impedance mismatch will still allow a signal to get through, but it is not optimized. There are format converters boxes that will properly do the conversion.

Get yourself a Monarchy Audio DIP (believe it stands for "Digital Interface Processor", there have been a few versions, they aren't very expensive new or used). This small, well-made box will take your S/PDIF and convert it to AES/EBU, while also providing electrical isolation between the source and DAC (just in case the spurious noise is caused by something else), as well as performing jitter-reduction. (Place the DIP away from other, line-level components to the extent that you can, particularly phono preamps.)

Yes, get the Monarchy DIP, not only does it solve your connection problem, but also reduces jitter... quite noticable improvement. You can find them used here on Audiogon ranging from $100-200 depending on type.