I2S connection inferior to XLR?

I am listening to Jays Audio CDT2 transport connected to DS Sr. DAC.

Surprisingly, XLR connection sounds noticeably better than I2S, the latter lacks high frequency extension. The cables are the same (AQ Carbon). And I hear no difference between XLR and RCA connections (although the RCA cable is different).

What can be going wrong in my I2S chain?

interesting. it may be SPL. XLR’s can add a few extra dB’s to the party.
try downloading a dB reader, and compare between the interconnects.
it may be possible you are picking up on ‘louder’ sound…?

It maybe that one transmitter package is better than the other. It could be a variable with your system. That is why manufacturers offer multiple options to send and receive. Sometimes one just works better in a particular situation.

I would not worry about it too much, and let your ears enjoy.

Do you mean that the transport’s I2S output is not particularly well engineered — compared to XLR or RCA?

I assume that Sr.’s I2S input is good enough …

No, I am confident that the SPLs don’t differ much. I change between inputs “on the fly” and they are equally loud.

By “XLR” you mean “AES/EBU” right? XLR has a difference impedance standard and is meant for analog use. AES/EBU cable is intended for digital.

Note that less than perceivable differences in volume can affect which source is preferred.

I’d check with another I2S cable. This one is cheap enough to try and is well regarded:


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The hdmi cable is likely not to blame — a cheap cable sounds exactly the same as AQ.

It may be that the aes/ebu input/output connections are providing better galvanic isolation between your components than your I2S connections.

Does subpar galvanic isolation particularly affect high frequencies?

Yes, not as well engineered or possibly not as well executed.

XLR connections are only 6dB hotter in the anolog domain. The same does not apply to a digital AES/EBU connection using an XLR connection in the digital domain.

If this is the case, I would be looking to replace the AQ cables. It very well could be a cable-centric cause, and a different make/model may be the solution. The lending library at The Cable Company is a great way to test drive a cable without committing to buy.

Most importantly, system synergy does not always align with our expectations. The impedance rating on each of these connections is different. And while i2S is generally the best means to connect a source component to the DS DAC, it’s certainly not an absolute.

While your observation that the AES/EBU and Coax outputs sound better than the i2S output in your particular system (cabling included) may be a surprise and even incongruous with others’ experiences, it does not necessarily amount to a problem - just an interesting difference.

Use what sounds best, regardless of the connection type.


you are a genius JeffofArabica. the 'ol smoke em if you got em proverb. :man_student:

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From a Ric Schultz modified Oppo 203 to a DS Sr, I run two connections, a PAD Neptune coax/iFi spdif iPurifier Wwith an LPS, and a PAD HDMI cable from an Oppomod HDMI/I2S card (I prefer the copper PAD to the old silver PSA I2S-12 cable). The difference between the two is so small as to typically be undectable (tho I can’t easily compare DSD files). Both sound very good. So I guess it just depends, like Jeff suggested.

@highstream what LPS do you use with your SPDIF iPurifier?

Right now, a Core Audio Technology Kora that I had been previously using on my desktop system to power a JCAT USB card. Core Audio is now defunct and the Kora was its next to last model, which I was able on someone else’s trade-in not long before they went belly up. Fortunately, it is 5V, which the iFi takes. I have a Paul Hynes SR4 on order, scheduled to be part of late April’s production. If it works out as expected, I’ll be selling the Kora inexpensively.

Actually I think i might be able to offer a possible techincal explanation. Check on the front panel of your DAC to make sure that pre-emphasis is not on. In the dsj this shows as an E on the display. Not sure what the senior displays but i know it will show something if it’s on. If it is showing that the i2s signal has pre-emphasis then you need to consult with the manufacturer about how to switch this off. I found that i2s was vastly superior to the other inputs on my dsj so I’d do a quick check on this.

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Hmmm … that is an intriguing possibility …

But I don’t see an “E” on the display or anything else that would look like preemphasis to me.

Moderator, can you let us know please how is preemphasis indicated on DS Sr.?


See the second dot down on the left

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