Encode audio in S/PDIF format

[Pavel_47]

Hello,

I'm looking for a simple solution to convert microphone audio to S/PDIF stream.

I wonder if there is a single device that accepts mic audio as input and outputs S/PDIF stream?

Thanks.

Pavel

 

[MaxwellsEq]

You need a microphone preamplifier followed by an Audio to Digital Converter (ADC) with S/PDIF or AES-EBU output. Lots of products in this domain are USB based, which I presume is extra electronics that you don't need.

 

[Pavel_47]

Thanks.
For the moment I see the setup as following:

• microphone preamplifier
• PCM1808 (the cheapest audio ADC from TI, 24-bit, 99-dB SNR, 96-kHz stereo ADC with single-ended inputs) that povides I2S stream
• some S/PDIF transceiver (e.g. DIX4192-Q1 from IT), that accepts I2S stream and convert it to S/PDIF

All "more integrated" solutions are welcome.

 

[raindance]

Behringer UCA202 or UCA222 with a separate mic preamp. This will give you optical out.

 

[jensgk]

A RME Babyface (any generation) operating in "Stand alone mode" will achieve that. They have built-in microphone preamp, and the quality is generally very good. The first generation can be found on Ebay.

 

[Pavel_47]

I'm talking more about IC solutions, not off-the-shelf products. I need digital audio to transmit over a custom media channel.
The digital audio (i.e. S/PDIF stream) have to be applied to a LED driver.

 

[Joachim Herbert]

I'm talking more about IC solutions, not off-the-shelf products.

Quite ambitious, given you start with zero knowledge.

 

[Pavel_47]

Quite ambitious, given you start with zero knowledge.

What makes you think I have zero knowledge ?
Did you find a particular detail in my question that shows that I have zero knowledge ?
Is it your usual participation in the forum to assess the knowledge of forum users or sometimes you provide an answer that counts?
Thanks.

 

[DVDdoug]

TI makes lots of audio related chips. It wasn't hard to find an ADC chip with S/PDIF.

I'm not sure if you'll find a single chip with a microphone input but an op-amp preamp is trivial compared to an ADC. And there's probably an advantage to isolating the low-level microphone signal from the digital. ...Digital noise can be a challenge if it leaks into the analog.

"Soundcard chips" are common but most regular soundcards have low-quality preamps and S/PDIF isn't that common. And soundcards have unbalanced mic inputs so they don't work properly with pro mics, and they don't work at all with phantom powered studio condenser mics.

I'm looking for a simple solution

I guess you know that the engineering and construction isn't going to be "simple", quick, or inexpensive, even if you end-up with a "simple" device.

 

[Pavel_47]

Yes, PCM2903CDB could be a solution although it has some unnecessary (for me) features like USB which raise the price to $8.5.
Thanks anyway.

 

[Berwhale]

I'm looking for a simple solution to convert microphone audio to S/PDIF stream.

Many members will interpret 'simple solution' as a single box consumer or pro device like the interfaces some have suggested. You should rephrase this to make it clear that you are seeking a single IC solution (not everyone is an EE here!).

...and welcome to ASR!

 

[Joachim Herbert]

What makes you think I have zero knowledge ?

Did not mean to offend you. Just would have thought that somebody who knows how to do it also knows what it takes. Stupid me.

 

[MaxwellsEq]

A good place to start may be here: Cirrus Logic ADCs

 

[Pavel_47]

A good place to start may be here: Cirrus Logic ADCs

Thanks. Well ... it's not easy to select the right device at Cirrus Logic. The selection table is not as well done as at TI or Analog Device.
These ADCs seem have I2S output which is not the same as S/PDIF stream.
There is CS8416, that provide S/PDIF interface, but as input. I haven't found any device that provides S/PDIF on both sides - input and output.

 

[Pavel_47]

Many members will interpret 'simple solution' as a single box consumer or pro device like the interfaces some have suggested. You should rephrase this to make it clear that you are seeking a single IC solution (not everyone is an EE here!).

...and welcome to ASR!

Ok, noted. Thanks.

 

[MaxwellsEq]

Thanks. Well ... it's not easy to select the right device at Cirrus Logic. The selection table is not as well done as at TI or Analog Device.
These ADCs seem have I2S output which is not the same as S/PDIF stream.
There is CS8416, that provide S/PDIF interface, but as input. I haven't found any device that provides S/PDIF on both sides - input and output.

I wonder if it's a consequence of the market for ADCs. They are either part of multichannel digitisation in studio work; or are part of "interfaces" - effectively boxed up soundcards, which need USB for computer control and recording. So there are some good, single box microphone to USB products. A real-time (non-USB) conversion to SPDIF is probably not a common standalone requirement.

 

[jensgk]

I'm talking more about IC solutions, not off-the-shelf products. I need digital audio to transmit over a custom media channel.
The digital audio (i.e. S/PDIF stream) have to be applied to a LED driver.

You should have made that clear. I am not sure you are in the right forum then. ASR is more about end user products, although there is some electronics discussions in few places.

 

[Berwhale]

You should have made that clear. I am not sure you are in the right forum then. ASR is more about end user products, although there is some electronics discussions in few places.

To be fair, there are plenty of members who are EE's or knowledgeable enthusiasts who can assist with this type of query.

 

[voodooless]

TI makes lots of audio related chips. It wasn't hard to find an ADC chip with S/PDIF.

I don’t think you can actually use the chip without USB. Everything goes though the USB controller:

 

[sarumbear]

I'm talking more about IC solutions, not off-the-shelf products. I need digital audio to transmit over a custom media channel.
The digital audio (i.e. S/PDIF stream) have to be applied to a LED driver.

https://www.ti.com/lit/ds/symlink/pcm3052a.pdf

https://www.nxp.com/docs/en/data-sheet/UDA1355H.pdf