I have no experience with AES/EBU or S/PDIF technology.  In what application would I use these?

Basically, I'm trying to maximize my input into my VS-700.  I tried running the AXE FX II into the AES/EBU through an XLR cable; it worked, but the tone was very noisy and distorted.  

I have an 8-channel preamp in through the ADAT in addition to the 8 pre-amps on the VS-700.  I also have the auxiliary on the board.  Is 17 simultaneous channels the only option?

Thanks!

Hi Erypsus,

Since you're using 8 channels of ADAT you must be using either 44.1 or 48 kHz sampling frequency, this means that you should be able to access 2 more channels (1 stereo pair) via the 'Digital 1' input which physically utilises either the coaxial or AES/EBU input. These are mutually exclusive connections, so you need to chose either 'coaxial' or 'AES/EBU' in the interface editor software. 

These 2 + 8 ADAT, 8 analogue and 1 Aux give you 19 total ins at 44.1 or 48 kHz sampling.

Though I'm not absolutely certain, I could imagine that the high impedance of a regular XLR mic cable (which often have grounding resistors fitted at the XLR terminals) is causing the distortion you're hearing with your AXE FX. I'd recommend using dedicated AES-XLR cables rated at 110 ohms internal resistance, the standard for this technology. As I understand it, AES cables can be used for analogue signals but mic cables aren't suitable for transmitting AES digital signals, especially over any distances.

Good luck,

J 

Thanks so much, that was very helpful.  I'm pretty sure it's just the cable; I was trying just a few different standard microphone XLR cables.  I will order an AES XLR cable now!

Are you shure your clocking is ok?  Which unit is your master clock?  

I ask because what you describe look like something I've experienced with a unit not clocked properly.

The way it look is that your 8 channel preamp strip is your master clock and the VS-700r is slaved to it via ADAT (digital 2 selected somewhere in the I/O editor clock selector).  If that's the case, then your Axe fx (Nice! Want one!!) is not synced to anything and sound like s**t.

So if all the above is the case, you must send a clock signal to the Axe fx. Look like the only way is via spdif, so you can connect a spdif cable (a special RCA cable with a 75ohm load I think...) from the vs700r spdif out to the Axe spdif in. Then set the Axe to be slaved to the spdif clock signal.

If you do this, it will have to be all spdif I/O, from and to the Axe fx. But there's no sound difference between AES and spdif, unless you need more than 10 foot long then that's what AES is designed for.

If you need clearer explanations just ask, or sorry if something above don't apply to you!

V-Studio 700 system / Sonar X1d expanded / Cakewalk A500s / FX-8120 / 60GIG Sata3 ssd OS drive / 120 gig Samsung ssd project drive / 990-XA-UD3 MB / Firepro V4900 / 16gig ram / 500GB WD backup drive / Fruman HDR-6 + 2x HS-6 / S-patch plus / RME ADI-2 / Swissonic AD96 / Presonus Eureka / Joemeek VC6Q / Heil mics / Blue Sky Prodesk 2.1

This is a good point Dyonight.
Best to make sure all your digital modules have an appropriate and locked sync before spending money on new cables. I wouldn't want to suggest you spend money unless you know you need to.

Either way, it'd be great to hear how you get it sorted.

J

AES/EBU is digital, XLR is analog. What are you running into the AES/EBU?

Craig DuBuc

The term 'XLR' is a bit misleading since 'XLR' actually refers to the socket connectors terminating the cable not to the intended use of the cable. The cable can be optimised for an analogue or digital signal, the sockets will appear identical. Digital ins/outs may also use the s/pdif (Sony/Phillips) coaxial connection which is also commonly used for AES interconnects just to complicate things further.

Erypsus, did you manage to get your AXE FX working nicely?

Best,
J