SPDIF & ADAT workflow

[Nymphomation]

Hi, kind of two questions here - any help appreciated!
I'm considering upgrading my audio interface (Tascam US1641) and a lot I've looked at have ADAT and SPDIF connection. Infact, I think my Tascam has SPDIF connection.

My question is, how do I best utilise these connections?

My understanding of ADAT is that it needs to be hooked up to an ADAT interface, which has 8 ins/outs. And I'm guessing the quality of this interface is pretty important? No point in getting an high quality interface and then running ADAT to a low quality ADAT interface? Behringer do one for £150, I'm guessing it's not going to be anywhere near the Focusrite one. Am I on the right lines?

I really don't get SPDIF at all, I've googled it, tried to find out more. What kind of devices can you hook it up to, just CD/DVD players that have SPDIF? Or can I use RCA adapters and hook it up to my drum machine/synth's standard 1/4inch stereo outs? I think I've seen SPDIF converter boxes for about £50 - is this a way of doing it?

It seems such a waste to have these inputs and not know how to use them! Thanks in advance for any help

[normen]

They're both just digital interfaces, ADAT has 8 channels and S/P DIF has 2 channels. So yes, you'd have an ADAT interface that converts from analog inputs to ADAT and if you connect them to your soundcard you'd get the analog inputs as inputs to your "ADAT" inputs in the driver on the computer. The same is true for a S/P DIF device, be it a two-channel mic preamp or a CD player. The thing you have to account for is syncing though. Because all digital devices run on an sample rate clock (thats what the 44.100Hz you can set means) one of the devices has to sync itself to the other device. For an analog-digital converter that outputs ADAT you should sync your sound card to the analog converter, to minimize the jitter caused by the A/D conversion. S/P DIF largely manages to auto-sync itself, so you don't need to explicitly specify a master device (though behind the scenes ofc one of the devices will be the master).

[Nymphomation]

Thanks for the reply Normen. Do you use ADAT/ SPDIF, and if so what interfaces do you use?

So with SPDIF, if I want to utilise the inputs on my device, do I need some kind of special Digital to Analogue converter, specific to SPDIF? Would I potentially loose quality doing this? The only devices I've seen look like cheap plastic things (not to say they won't work..)

[normen]

I am using ADAT in various ways, to connect to a Behringer X32 Rack, using a SM Pro Audio PR8 analog-to-digital converter and in various ways at work, you can get a good line-to-adat converter from 150€ on (SM Pro Audio Q-ADAT) or spend 4000€ for a multichannel mic preamp.. http://www.thomann.de/gb/search_dir.htm ... at&bn=&gk=

S/P DIF is also just a digital interface and theres no loss in quality from the connection itself if its properly synced and your audio interface has a proper S/P DIF input that regenerates the audio clock.

[Nymphomation]

Thanks for the info Normen. I looked into the Behringer ADA8000, and it has surprising amazing reviews - fooling a lot of Gearslut users in a blind test VS an Aurora Lynx which costs 10x as much!

I get that there's no loss in quality from the SPDIF connection, but it would have to be converted using something like this http://www.thomann.de/gb/search_dir.htm ... IF&bn=&gk=

Was wondering if you have any experience converting analog to SPDIF, as that's what I'd want to do - take the analog signal from my drum machine/synth and convert it to SPDIF. If those boxes would do the trick, £32 for an extra two inputs seems like a good investment!

 

[normen]

Sure, most of these are fine, especially as they use line level on the analog side. Just be careful not to have too long cables with unbalanced connections (RCA, "mono" jacks) My personal experience with the ADA is that you need a lot of analog gain with mic inputs and that the S/N ratio becomes less than ideal with more gain. But thats the only thing you really need to care about with all of this. Despite the fact that some companies put great emphasis on the "quality of their A/D converters" the truth is that the A/D converters themselves that are on the market are all great and have way better performance than any analog part of the signal chain. As long as you have a good clock / reclocking inputs on your audio card (some cheap audio cards simply use the clock coming from the other device which can cause jitter) and good analog parts theres no problem.

[kloeckno]

I have a cheap $30 SPDIF-to-analog convertor, and so far it seems to work fine! I just got two RCA-to-1/4" convertors and now I have two more outputs for my soundcard for sending out my band's vocals on their own channels for gigs. I just use short cables going to DIs to minimize interference on the unbalanced cables.

Of course that's kind of the reverse of what you're asking, but the cheap D/A or A/D convertors are pretty good if that's all they're doing. You wouldn't want to use a really crappy preamp going into a cheap A/D for example.