i2S clock question

So, I’ve recently added a Denafrips Iris DDC to be able to feed my Musician Pegasus R2R DAC via its i2S input via its HDMI i2S input, and compared to feeding it directly from an SPDIF or USB input the positive results are significant and very apparent.  While I’m aware of the separate internal paths of the i2S connection versus other connections and despite many searches, I can’t find a definitive answer as to how the clocking works in the end.  I know the Iris re-clocks the data and sends it via a separate line within the HDMI connection to my DAC, but I can’t find a clear answer as to how the re-clocking of the DDC works in conjunction with my DAC. Does the re-clocking of the DDC override the re-clocking of my DAC with an i2S connection, or does it just feed my DAC a cleaner signal that allows my DAC to work better and more efficiently given its own re-clocking abilities?  Am I subject to the re-clocking of my DDC alone or is it a combo of my DAC and the DDC working together with an i2S connection?  Thanks for any thoughts and experience!


in my honest opinion, i2s is a superior protocol

hmm.. i think this is a question for the company. However, I believe the "clock" becomes more stable, therefore the signal; much like having a separate master clock on a CD player - that’s BNC, but CD player outputs also use i2s. Hardware almost always outperforms software. What you’ve added here is almost like me selecting CD input on jriver, jitter correction and 4x. This results in improved PRAT -pace rhythm and timing. --> is this the improvement?

In theory, they would be seperate units. In practice, they would be just one unit, optimized for better performance.The Femto TCXO and FPGA would be doing the heavy lifting...

@soix The Iris re-clocks the signal it receives from your source, reducing jitter and converting the source signal to I2s, AES, Coax etc. It does not slave your DAC.

The Iris can also be connected to a Terra or Aether clock to further reduce jitter.

However connecting a clock IME to your source would bring the greater benefit.

I forget your source component.

@lordmelton My source is an iFi Zen Stream that I quite like for the price.  So, from what you’re saying, my Musician Pegasus DAC clock is still working with the i2S connection?  That’s really what I’m trying to nail down here, and after doing a pretty thorough search I couldn’t find a straight answer to this fairly simple question.  Argh. 


In your test with the Iris added into the chain from your streamer to dac are you saying that the resulting signal sounded better over I2S than it did with SPDIF or USB when coming from the Iris? I would think that all outputs from the Iris would be equally as good with respect to the improvement in clocking.

@lordmelton is correct in stating that the clock in your Pegasus is still performing with the Iris connected. If you heard an improvement in signal quality it would lead me to believe that 1) the clock in the Iris does a better job than that of the Pegasus 2) it’s possibly the combination of both working together that has produced the difference. I’ve read threads on signal clocking where the owner used two Mutec reclocking units in a daisy chain prior to a dac and claimed there were large improvements in the audible result. 

I2s and Ethernet inputs on the better dacs are superior sounding compared to the other inputs, even if you include all the hacks/tweaks that people apply to some of those protocols.

I would take an fpga based dac over a pure hardware dac for many reasons and I have. I got new firmware every 6 months that improved the sq for free. I also got new firmware that doubled the dsd up sampling as well as implementing MQA, again for free.

I have friends that have dacs costing 5 digits that have to pay thousands to upgrade for MQA and these dacs can’t improve their sq so they become out of date.

@designsfx To be honest, I haven’t yet tried the SPDIF out from the Iris because I went right to the i2S connection.  I recently significantly upgraded my SPDIF digital cable so I’ll have to do a comparison and I’ll get back with my results.  My guess is that even using a $4, 6” Monoprice HDMI cable over i2S is gonna be a high hurdle for SPDIF to surpass even with a $660 SPDIF digital cable, but it’ll be interesting to see/hear. 

@soix Before you connected the Iris your DAC’s USB input and card most likely took over processing duties from your Zen.

However that is not possible with the Iris connected.

As i said earlier the Iris is not a clock, it’s a re-clocker, so it re-clocks the incoming USB signal from the Zen and passes that cleaner signal to the DAC.

I2s will generally sound better because it’s far less prone to jitter than other digital connections. RJ45 will probably sound better than HDMI.

Please remember this is USB being converting to I2s so although it’ll sound good it’s never going to sound as good as native I2s direct from a source component, streamer, CD/SACD etc.

With that said, it would be interesting to know what type of sound signature the Iris adds (or not) to the input signal.

@designsfx That should be easy to ascertain by using just the USB with and then without the Iris. Apples for apples.

"So, I’ve recently added a Denafrips"

This is a genuine, sincere, and honest question I pose because English is not my first or even second language and I struggle with it challenged by not having much exposure to native speakers of English, which is a very difficult language I can say because I speak a few at least in part.

I have over the last few years encountered increasingly the beginning of sentences in English with the word "So." Is that important and please explain what "so" means in this context.

Thank you for helping me with my English.

@soix  and all,

I’m so glad a clock question came up, because I’ve been a bit confused.  So, I have a Denifrips Pontus ll. If I add an Iris reclocker, I’m assuming it will sound better, but let’s say I buy a Venus ll DAC or a Terminator ll,  will the Iris improve the sound as well? Or will the better DAC have a better clock and so need a better reclocker to make a difference?

@curiousjim Yes, but it’s not just the reclocking but also the ability to take advantage of your DAC’s superior i2S input with an HDMI cable, so it’s really like two benefits in one.  On my Musician Pegasus DAC, which has a strong resemblance to the Pontus ll as they come from the same factory, the improvement with the Iris was not small. 


I’m thinking the next time a used one comes up, I’m gonna snatch it up. Might even buck up for one of those Audioquest HDMI cables. They have a couple that are less than $100. I know that RCA to USB made a big difference and l’m definitely interested to hear what i2s does.

Oh, what power cord are you using with the Iris?


I would advise you take a quick scan of the posts at audiophile style regarding clocking the Iris and Terminator. I faintly remember a thread running there that concluded the Terminator’s clock was at a higher level and basically saw no improvement when paired with the Iris. Not for sure- but it costs nothing to check.

@curiousjim et al-

I seem to have mistaken the reference to the Iris in my previous post- the thread mentions a device called a “Gaia”. Either way the subject of the discussion “jitter/noise” testing is interesting. I believe this thread was created by the same person who made the popular MQA Myth video seen on You Tube.

Jitter/Noise Testing

@curiousjim So,I think the Musician Pisces and Leo provide greater value than the Denafrips Iris or Hermes.  I bought a used Iris for what would be the same price for a new Pisces. Also, I’m not convinced paying up for an HDMI cable is worth it for i2S.  Length may be as important as quality, and I’m using this cheap Monoprice 6” HDMI cable and am getting excellent results. At some point I might upgrade to a DH Labs HDMI cable, but I’m in no rush given what I’m hearing, and I’ve heard several others state they don’t get big improvements by upgrading their HDMI cable for i2S.  Just my $0.02 FWIW.  I’m currently using the stock power cord with the Iris, but when I upgrade I’ll use the Cullen Crossover PC.  Hope this helps.




I know nothing about Musician or Cullen, so I guess it’s homework time.😁

Thanks fo the information.

@curiousjim Look at Musician as more affordable Denafrips.  They come from the same factory and share more than a few internal components and design parameters.  Denafrips likely wins on resale value if that’s important.  Cullen was recently bought by Wyred 4 Sound, but as far as I know he’s still involved with producing his high-value cables. Other good and high-value cable companies to check out are Audio Envy and Zavfino.  I now buy cables used whenever I can because they’re easy/cheap to ship and the discount is usually 50%+ versus buying new.  I recently bought an awesome used Acoustic Zen MC2 SPDIF digital cable for $200 that would cost $660 new.  What???  Best of luck.