Denafrips Pontus II Clicks Or Static?


There have been some who have reported clicks or static occasionally with their Denafrips Pontus II DAC units.  And there is a test measurement review of the Pontus II 12th on the golden sound website talking about the following:

"When DACs oversample, they can sometimes encounter a situation where the reconstructed/interpolated waveform goes above 0dBfs (the maximum possible digital value)."

"The Pontus 2 is susceptible to intersample overs, and unfortunately, in a particularly bad way."

"The Pontus 2 does not clip, but instead when a sample value reaches above the maximum, it ‘wraps around’ to the minimum negative value, causing a huge sudden transient which will be very audible and may appear as crackling/popping."

Has anyone with a Pontus II encountered this anomaly when playing CDs?  If so, can you elaborate about that?  I am aware that the Pontus II can be firmware upgraded, so if this is an occasional issue, it could be eliminated with an upgrade.

 

 

fastcat95

@whipsaw - I am making some assumptions here on the exact implementation of Denafrips' designs, since they have never really published a detailed description.

As I understand it, the input data is clocked into the FIFO using the source device's clock (embedded in the SPDIF signal), and clocked out of the FIFO using the DAC's internal clock.

If the clocks are different enough in frequency, eventually the FIFO will overflow (if the source device's clock is faster) or underflow (if the source clock is slower). So, yes, CISCO's explanation is basically correct.

I'm not an expert on modern DAC implementation, but I believe that many DACs (particularly lower priced DACs) use a phase-locked loop to adjust the DAC's clock frequency to match the source clock. They may also use a FIFO so the PLL can be slow responding to minimize jitter. But a PLL will still not be as stable and jitter free as a fixed crystal oscillator (particularly an temperature controlled oscillator).

I suspect the reason that the problem was less common (or non-existent) with the Terminator and T+ is that the clock used in these DACs is higher quality (more accurate) than the clocks used in the lower priced models, and these DACs probably also tend to be used with higher quality sources (which have more accurate clocks). I have not heard that the FIFO implementation is any different, although it's possible that larger FIFOs were used. 

I also suspect that many higher end DACs use a similar approach to Denafrips and just did a better job with the FIFO management (perhaps using the same approach that Denafrips is now using). 

Thanks @jaytor – I appreciate your technical insights. I tend to believe that it was likely a (Denafrips) clock issue, but whatever the exact cause, I hope that the latest firmware has resolved the issue for owners of the affected DACs. 

 

I had the same issues about a year ago, Alvin had me do a firmware upgrade, that resoled the issues for 90% of the time, a month ago I did the new firmware upgrade, sound was good more detail, started checking left and right plus polarity, when I would Roon and play back was DSD left and right where backwards, through pcm play back it would be just the opposite and phase was off. Alvin replied that I had to change the phase through some programing he gave me, did and I thought problem was resolved, not , I had to go through 8 steps to get the correct I2s config, that also was effectting left and right ch.After all that now the small clicks and static are back. Just sent Alvin an email, had to share.

I have had this issue, but isn't frequent enough in nature to be a problem. At least to me anyway. The noise I get from my Pontus ll is a extremely soft low level pop, which happens maybe twice during a 3 hour listening session. While I would appreciate dead silence, it isn't that offensive to bother me. Pops, clicks, and snaps from vinyl are FAR more annoying than this.

@All

i just finished this entire thread and boy my head hurts.  The only reason I landed on this was after listening to Audio Science’s Amir explain the jitter, Dac clock vs source clock, pll and how that works and noticed he had not tested the Pontus ii, so I went a googling.

i purchased a Pontus ii 12th Anv. Which arrived today and is sitting boxed in my basement.  Now I’m afraid to open it 🙄.  Seriously, it’s replacing and old Burson DA 160 which I’ve loved over the years, but it seems to be choking on the new Eversolo A8.  Anyway, I am coupling it to an Audiophonics HPA Purifi D class and will report back should I hear any of those pesky pops.