SDR clocking issues

[gerax]

Hi all

searching the internet in the desperate hope of finding some answers to the issue I’m having with my trusty SDR...

Here’s the thing: I use the SDR as a backup recorder in my live recording rig. Primary recorder is a MacBook Pro/Apogee Ensemble Thunderbolt interface.
Now, I use the 8 mic pres on the Apogee and an external Focusrite preamp (ISA 428) with AD converter card.
I feed the Mackie the Apogee mic pres and the FF pre via ADAT to both recorders so that I can have the same exact signal on both.

This is where the fun begins: I tried every possible clocking setup, including ADAT A, ADAT B, WC and Internal but as soon as I connect the second ADAT equipped preamp I get clocking issues in the form of spikes on the Mackie (the Apogee works fine and I can have all 16 channels in Pro Tools) and no signal.

I tried to use the Apogee as a master clock and feed word clock to both the FF preamp and the Mackie, I tried to use the FF as master clock but no luck.

Reading on the scarce infos I’ve been able to find on the internet I learnt the SDR always had clocking issues.
I know I’m making up a pretty involved setup as I’m sending digital streams to two recorders from multiple preamps, and that I could use analog outputs from the FF preamp but…you know…I cannot stand it whan things that should work aren’t working the way I want them.

Has anybod managed to successfully feed 16/24 tracks via ADAT to the SDR? If so, what clocking setup did you use. Do you think a dedicated WC generator could fix this?

Thanx

L.

[doktor1360]

Do you think a dedicated WC generator could fix this?

Don't take this as the Bottom Line, but from what you're describing it sounds about right. Good quality coax cables properly terminated & quality 'T' connector(s) would help reduce if not eliminate any possibility coax noize/interference. Once you've got that 'heartbeat' solid in your setup, only the audio configuration and physical connects remain. At face value anyways...

Hope this was helpful in some sorta way...

However, you knew it was coming so here it is :
[Standard Mgmt Disclaimer] - "Your Actual Mileage May Vary..."

Peace