Today’s tip is based on a question we hear frequently: "Someone told me that I could run an AES format digital signal into a S/PDIF input, and vice versa; it will work just fine. Is this true?"
The answer? "Probably, maybe, sometimes" (…no wishy-washy answers from those decisive guys at inSync!)
As formats AES/EBU and S/PDIF are very closely related, although there are very slight differences in the digital information sent. In many cases it is possible to run one into the other with good results – it really depends on the two devices you are connecting. Some devices, like Kurzweil samplers, actually allow you to switch which format is carried on their digital connections, which solves the problem.
The two formats are a bit different electrically though. S/PDIF is high impedance and unbalanced, while AES is a low impedance balanced format. This means that AES will survive long runs much better (up to 100 meters) and will have less problems with RF interference. The levels the two operate at are also different, which might cause distortion problems when running one type into the other.
Our advice? Your best bet is to run AES into AES, and S/PDIF into S/PDIF. If you must interconnect them, use an appropriate format converter. But in a pinch, you can try running one into the other for a quick transfer…