tnt audio review of i2s pci express interface

[2channelaudio]

No point debating whats better whats worse.
Proof is in the SQ.
Not a cheap try..... unfortunately. especially if you are purchasing in $aud...

Maybe a pci bitcoin riser cable could help get the PCI card closer to your dac......
Not sure this is ideal either.?!
Or simply use a 0.3-0.5m good quality hdmi cable.

FYI...
I have measured many Kordz hdmi cables with a $7k quantum data tester.
The pro range have 0 bit errors to 15meters.
The PRS range have again 0 bit errors to 18meters.
Their excellent cables... Maybe this qualifies a short hdmi cable as suitable for I2s transmission.. ?

I think if you keep terminations hdmi, and use a reputable cable manufacturer results should be ok.
But in the land of audio it could go either way... lol

Interesting product.

[jkeny]

Yea but I think we are well beyond data loss or bit errors affecting SQ, right?

[DaveF]

Yea but I think we are well beyond data loss or bit errors affecting SQ, right?

Absolutely. Unless we're trying out up some DIY job that has cables soldered in etc then it would be worth checking the I2S signals on a scope at the RX end to check skews etc. Very easy to do.

I dont know why the concern here over cable length for I2S. Termination is more important given the non standards here. HDMI or Firewire is an already made solution on that front.

[wademcinnis]

This is not the first instance of this idea.

Dave Davenport and PSAudio have offered I2S adaptors for quite awhile using HDMI cables.

Dave's was easily used with a JULI@ sound card and PSAudio's was intended for use between their transport and DAC.

Length of cable is not much of a problem with these implementations because they are amplifying the signal before sending it down the cable. Nonetheless, even with this Davenport recommended no more than 2 meters of HDMI cable.

I thought it was well established that the length of cable is very important with raw I2S. Of course, you can do anything you want as long as you are willing to accept the compromises. Termination becomes important with any type of signal the longer the cable. AS dim as the raw I2S signal is I have never before heard of a termination specification that will negate this.

Would be interesting to hear how this device compares to WaveIO. The question is whether it is best to use USB to send the information to a card near the DAC (WaveIO) which then uses a very short cable to connect to the DAC or to convert within the computer, amplify the signal and use an HDMI cable to send this amplified I2S to the DAC?

I have tried both and tend to think the WaveIO approach is better.

[shoom]

Hi All

My first post but I thought I’d take the plunge with this thread as it’s something that interests me quite a bit.

Ok I agree that sending I2S down a cable which is longer than a few CM is asking for trouble but that’s not to say that the idea with a few mods is a nonstarter.

It just needs a little more thought than put in by the manufacturer IMHO.

I’ve been using a pair of these

http://www.twistedpearaudio.com/digital/teleporter.aspx

To send the I2S signal from my WAVEIO to Buffalo DAC for quite some time now and it works a treat in my set up.

The I2S signal is converted to LVDS (low voltage differential signal) by the first Teleporter and then back to I2S at the DAC by the second. It seems like a good way of circumventing I2S’s limited transmission distance. I have my WAVEIO on a short USB cable and then 10M of LAN CAT5 connecting to the DAC.

So possible? Yes but not without converting to a signal more amenable to transmission over distance.

So this board as is seems a little flawed but with a little more work it could be much better.

Just a thought.

Just warming up for a new Audio PC build and I2S is on the list.

[Crom]

Interesting post shroom and welcome!

I bought a second hand pair of the transporters for exactly this purpose a while back but haven't got around to trying them out. Rather than using them 'within the dac', I was planning to do the following:

windows pc > transporter 1 > network cable > transporter 2 > i2s input on Twisted pear buffalo.

I'm currently using a waveio and my primary motivation was to try the DSD file format that waveio doesn't do (until the long-awaited daughter board arrives, anyway). Secondary motivation was to take usb out of the chain. I hadn't spent enough time researching how to get a i2s signal from the PC to convert using the transporter. Also, i started to use Ian's FIFO re-clocker on diyaudio.com which also doesn't work with dsd content. So, I kind of borked myself before I'd even started but I'll get around to it one day!

[shoom]

Hi Crom

And thanks for the welcome.

It seems like you are heading in the same direction as me in trying to eliminate the USB connection and pipe I2S straight from the PC.

No reason for that not to work with the Teleporters with a sound card that has an I2S OP header.

My current set up is

Audio PC>short USB to WAVEIO>Teleporter>CAT5>Teleporter inside DAC case>Buffalo/Legato.

Its sounding pretty good this end and a dedicated PC card with receiver for the DAC end could have been a more fruitful approach from the pink faun producer.

IMHO the I2S thing is good sounding but ultimately a little limited by the short transmission distances and a little long in the tooth technology wise. I can’t just help thinking that there must be a better way of getting music from PC to DAC.

Maybe someone is working on that as we speak.

Let’s hope so

ATB.

[nige2000]

did i read somewhere that the pink faun pci e i2s actually converts pcie to usb to i2s?
think it was peter from xxhighend
if that would be the case its just an expensive usb card and i2s converter

are we stuck with usb to i2s ? is there a pcie direct to i2s chip?

keep thinking that a all in one box with pc and dac in it could be the best compromise
keep thee wires short and protected

shoom let us know if you find a good/better way to get i2s out of the pc rather than going through usb

[Crom]

quite an interesting read:http://www.raleighaudio.com/I2S%20Interface%20v3.1.pdf

and we're not the first ones here, nice thought about ripping the dac chip off a soundcard though!!

http://groupdiy.com/index.php?topic=51957.0

[shoom]

Hi Nige2000

Yes interesting subject and finding the right I2S work around is the challenge.

‘’pink faun pci e i2s actually converts pcie to usb to i2s?’’

Yes makes very little sense IMHO and has no real advantage other than eliminating the USB lead but some key PSU problems to overcome.

I was thinking more along the lines of taking I2S straight from the sound card into a Teleporter on short leads. The Teleporter then converts to LVDS which is much more amenable to distance transmission. Then back to I2S at the DAC. Now I’ve tried USB straight into the WAVEIO, straight into my Buffalo and compared to using the Teleporters.

To my ears I can’t hear any difference in SQ (Not saying that they don’t exist but just I can’t hear them) and the jitter figures seem pretty respectable and in many cases lower than most USB/SPDIF converter chips.

A better way.

Well I’m just in the process of starting a new Audio PC build so I may try to work that in.

But

I’m a little bit of a technophobe (read slow) and from a pre computer at school generation so I’ll be looking for a few hints when that comes around. I’m having a look at the Audio PC Build thread ATM and its dead good but I may just start a similar one for dummies like myself just to encourage a few more participants to build something nice.

We’ll chew over that some more once I’m ready to make a start as it could make for an interesting side project.

I’ll start looking for a suitable donor card.

Hi Crom

Interesting links and as you say nothing new under the sun but IMHO the sound card method does throw up a few other issues to address.

Maybe the most important being (yes the old chestnut) getting a good power supply to it which may be a little more tricky but not impossible.

BTW my WAVEIO has its own dedicated PSU so no Vbus connection which made a nice difference in my set up and to my ears.

BTW

It’s nice to have such conversations without being stomped down for daring to suggest that the above considerations matter.

ATB