Connecting the Kemper digitally to a soundcard

BjornNilsson · December 2, 2019 at 10:42 PM

The Kemper has a digital spdif output and my soundcard (UAD apollo twin) has optical inputs.

Is there a simple cable adapter I could use or do I need some sort of box to connect them?

digbob · December 2, 2019 at 11:21 PM

there are converters from optical to rca spdif available

look at amazon or similar for this

its the same protocol

BjornNilsson · December 2, 2019 at 11:49 PM

So I’d need a box like this:

LiNKFOR Bi-Directional Toslink to Coaxial Converter 192 kHz Optical SPDIF Toslink to Coaxial Toslink and Coaxial to Optical SPDIF Toslink Coaxial Converter Switcher with Optical Coaxial Cables https://www.amazon.co.uk/dp/B07ZNR4N9F/…i_nsz5Db0HKTSCM

I was hoping there might just be a cable adapter.

lightbox · December 3, 2019 at 12:58 AM

Yes, that's the kind of converters you need.

I had good results with this particular model:

https://www.thomann.de/gb/lindy_audio…dif_digital.htm

Be aware that you need 2 units if you plan to do digital reamping.

Regarding "just a cable adapter":

This doesn't exist because a cable in itself can't convert from an optical signal to electrical signal and vice versa.

tommyguitar · December 3, 2019 at 1:31 AM

Just FYI you will get equal sound with the awesome preamps and converters in your Apollo. Also, you will get less latency monitoring direct in Console than with SPDIF.

musicmad · December 3, 2019 at 8:04 AM

Quote from lightbox

Yes, that's the kind of converters you need.

I had good results with this particular model:

https://www.thomann.de/gb/lindy_audio…dif_digital.htm

Be aware that you need 2 units if you plan to do digital reamping.

Regarding "just a cable adapter":

This doesn't exist because a cable in itself can't convert from an optical signal to electrical signal and vice versa.

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Good post. OP keep in mind that the Twin doesn't have spdif output so you must reamp in the analog domain.

lightbox · December 3, 2019 at 8:23 AM

Quote from musicmad

keep in mind that the Twin doesn't have spdif input

Haha, true. Weird devices they are. Digital OUTput it doesn't have. I wouldn't even be surprised if someone told me that the UAD's ADAT input can't be switched to S/PDIF mode.

musicmad · December 3, 2019 at 4:28 PM

Ah sorry yes. Output.

BjornNilsson · December 3, 2019 at 11:38 PM

Quote from lightbox

Yes, that's the kind of converters you need.

I had good results with this particular model:

https://www.thomann.de/gb/lindy_audio…dif_digital.htm

Be aware that you need 2 units if you plan to do digital reamping.

Regarding "just a cable adapter":

This doesn't exist because a cable in itself can't convert from an optical signal to electrical signal and vice versa.

Display More

thanks for the link!
Would a cheap one not do the trick?

Is there really more latency going in digitally? If it’s a lot more it wouldn’t make sense for me to go that route then.

The only reason I’m planning to use the optical ins is that I can keep my analog ins free for microphones when recording acoustic guitars and vocals.

GearJocke · December 3, 2019 at 11:50 PM

I don't get any less latency using spdif.

lightbox · December 4, 2019 at 12:06 AM

Quote from BjornNilsson

Would a cheap one not do the trick?

It should work as well, just haven't tried this particular model

Quote from BjornNilsson

Is there really more latency going in digitally?

Sadly there is no easy answer to this, apart from the difference not being much.

It basically depends on many factors ... a few factors being:

1. Does your interface support "Direct Monitoring" (for analog and digital inputs) and do you use it?

2. If the answer to #1 is yes, what latency does the DA conversion in your interface for direct monitoring introduce?

3. Does the optical/coax converter introduce any amount of latency?

4. If you don't use direct monitoring but prefer to monitor through your DAW, how does the audio interface handle the conversion from S/PDIF audio stream to USB audio? Is there any latency introduced?

It's pretty much impossible to exactly tell what the result is unless we try with exactly the same setup you'll be using. It can differ with other setups/gear.

I wouldn't worry too much about this, it should be well below any perceivable difference, probably a couple of samples more or less.

BjornNilsson · December 4, 2019 at 1:03 AM

In that case I’m not that bothered. As long as it’s not notable and loads.

Stupid question:

Usually on digital signals you can send more than 2 channels. I’m guessing with the Kemper being a SPDIF Output I can only send stereo, right?
Would be awesome if I could send both the dry stereo and the effects stereo seperate through the digital outs.

lightbox · December 4, 2019 at 1:05 AM

Yes, correct. It's just a basic S/PDIF In/Out (2 channels). For ADAT (up to 8 channels) it would have been optical I/O.

BjornNilsson · December 5, 2019 at 1:26 AM

There’s an idea for the next version of the Kemper

dickjonesify · December 8, 2019 at 3:48 AM

Lots of good info here.

For those of you who haven’t used the UA interfaces: Their conversion and monitoring is crazy low latency and absolutely stellar.

For cheap interfaces, I’d say going S/PDIF is beneficial for my our sound quality. From my experience with UA, I’d say don’t bother. Analog is A-ok

ipran · December 8, 2019 at 3:30 PM

But UAD Appolo preamp is so good , you will missed that if you using spdif with coaxial converter