What is I2S

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Well, it appear I have been living in the cave for the last few years and don't know a thing about I2S.

Reading a few DIY DAC post and I2S input is widely used. Did a quick search and I2S appear to be an output from sound card.

What I like to find out - Is it compatible with the digital output from my CD/DVD player? Can I connect them to the I2S input on the DAC, like the D-I 16 DAC in the "Building the ultimate NOS DAC using TDA1541A" post?

Thanks for your info,
Sam
 
Hi.
I2S stands for "Inter-IC Sound". It is an interface protocoll for digital audio, used INSIDE cd-players, dacs and the like. It is rarely available externally. There are some products, usually expensive, that have a I2S output or input, in the form of a multi-conductor pin or multiple optical interconnects.

So, it is likely that you will have to modify a CD-transport if you want to connect by I2S to a dac.

Hope this helps.
-Alexandre
 
Making the connection

Hi SamL,

If you would like to connect your CD player to the octal D-I DAC or the D-I 16 DAC, there is no problem. I am very aware of the fact, people must be able to connect standard equipment.

If you don't intend to mod your CD player, all you need is the SPDIF to differential I2S interface, that is going to be designed soon. Just hook it up to the coax or optical SPDIF output, and connect the differential I2S to the D-I 16 or octal D-I DAC. The SPDIF interface has a on-board shiftregister reclocker that reduces jitter and produces similar sound quality as a direct I2S interface, the digital audio interface will provide Philips output format.

If you like modding, you could use the single ended I2S to differential I2S module, basically a small buffer. Another option is to mount the D-I 16 core / octal D-I DAC core close to the transport, using the plain single ended I2S interface. In both cases the transport must be able to output the Philips format.

I used a differential I2S interface (one twisted wire pair for each of the 3 signals) to minimize interlink jitter and interference. In practice even a 3 meter long differential I2S interlink works fine, producing very low jitter.

I hope this will answer your question.

John
 
I2S, which was developed by Philips is defined as three signals:

SDATA - serial data
SCLK - serial clock - usually 64fs
L/RCLK - delineates left and right data to demux them.

Most I2S interfaces defined by companies, such as Empirical Audio add a fourth signal:

MCLK - Master clock, can be 256fs or 128 fs

These signals are essentially the interface to most modern D/A chips.

The first I believe to try to standardize I2S was Audio Alchemy, who offered both a transport and DAC with the interface. Later, the follow-on company Perpetual Technologies also put the interface on their P-1A and P-3A. They used the mini-DIN, which is a really unreliable connector.

Recently, Empirical Audio and Northstar design are offering I2S interfaces using the RJ-45 connector common for Ethernet networks. Northstar has a Transport and DAC with I2S. Empirical Audio has USB and Wi-Fi computer interfaces with I2S and adds them to inputs on equipment, including several DAC's and the DEQX.

Steve N.
Empirical Audio
Manufacturer
 
Hi,
I will like to connect my PC to a perpetual technologies DAC by using the I2S connection.
The output from the terralink converter is I2S in RJ-45 form. The input of PT3A is a 5-pin mini DIN.
Does anybody knows the the conversion from RJ-45 to PT 5-pin mini DIN?
 
Thanks glt,
That's useful information & does show that I2S isn't simply a plug & play technology!

I have a question about using a Sabre DAC which will accept MCLK from I2S OR will allow a local asynchronous clock to be used. In this second asynch. case does the quality of the clock in the transmitter have any sonic influence?

I know that people have reported differences, in using the Sabre, between different sources so can anybody explain what is happening?

Edit: I have I2S from a Musiland to Sabre DAC & wondered if I2S from HiFace (with lower jitter clocks) would make any difference in this case as the clock is being re-clocked?
 
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