SPIDIF–AES/EBU interfacing.

[chrispenycate]

I basically live in a recording studio, and the console has basically AES/EBU digital inputs, and just a few (24) analogue, and one ADAT (8 tracks)

I've noticed that several of the keyboards I work with have SPDIF outputs (and sometimes inputs, too, but that's another problem; the AES/EBU receiver chips have clock converters on them, in the other direction it's word clock distribution). Now, I've checked, and the desk inputs will work with just an adaptor cable, at least for short distances, or a 75Ω- 110Ω transformer (that's an omega, for ohms, in case the site software turns it into a ?) but I'm an old style engineer who believes in balancing and levels for long runs.

If it were analogue, where once I would have put a balancing transformer, now I'd put an op amp circuit; I was wondering if a CMOS inverter chip would boost the level and give my antiphase drive, just needing a couple of resistors to match recommended levels and impedances. A little box, close to the keyboard rack, boosting the signal for the run to the machine room…

Has anyone tried anything like this?

[DorinD]

Maybe this could help: Interfacing AES3 & S/PDIF

[Zoran]

It is maybe better to use one diferential driver, then galvanic isolation chip (ADuM series)
and after that another dif to dif driver chip
.
or with just 2 chips first galvanic isolation + dif. driver + 2 x good power supplys + box
and You can have multiply output.
for the impedance matching use Pi or T networks not only resistors...
cheers