Qutest USB Clicks & Pops

I am using an Allo USBridge sig with a DigiOne Sig on top into a Chord Qutest, and I am using Ropieee XL as the endpoint software running in the USBridge. I am also using HQPlayer for upsampling. I have the endpoint set up so I have a choice of either SPDIF Coax or USB into the Qutest (its nice to be able to compare the outputs). The USB input goes to 768khz but I get the occasional white noise (seems to be a known bug with the USB input on the Qutest), so I have put a limit of 705khz in HQP for the USB – this doesn’t matter much as most of my material is 44.1 based. For the coax, the upscaling looks like is limited to 192khz.

I am finding when I use the USB input on the Qutest I get clicks, pops and glitches – more often than not they sound like clicks on an LP record. These are not present when I use the SPDIF coax. I would like to use the USB more as I am finding the upsampling to max frequency does have sound benefits, but the clicks and pops are annoying. Any ideas on causes or fixes for this?

One possible thing I am considering is one of those SRC-DX devices, so I can get max upsampling and use the BNC coax inputs. I have heard good things about this on here and elsewhere but any other experiences would be gratefully received – especially if anyone hears clicks and pops through it. I suspect not, but I would be happy to hear actual experience rather than my own guess.

Thanks for any suggestions

It looks like you’ve achieved what many think it’s the ultimate goal of a digital stack: to emulate vinyl. :wink:

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Have you tried reducing the USB Upsampling to say 192 and trying that?
If ok then slowly increase the Upsampling until you hit the clicks and pops again.

I did not have much luck with a Qutest , 384 was the limit from an Ultrarendu before I got similar noise artifacts.
Even though the qutest is supposed to be good for 768.

On HQPLAYER, what filters are you using?

Are you using HQP embedded or Desktop?

Yes, and the clicks get worse when I play my digital files at 45RPM

Interesting, thanks. I tried 192 for a few hours today and didn’t hear any clicks but I was working at the same time so I can’t be definite. I went up to 384 and I did hear a few clicks. Worth experimenting more with I think.

However I do want to go to max res of 705/768 because that’s when the first stage of upscaling inside the dac is switched off - I think it does make things sound better.

All sorts of filters - the clicks are common to all I have tried. HQP embedded.

Please advise the spec’s on the computer you are using for the HQplayer embedded.

I did some more tests and found the following:

  • Clicks and pops occur on USB input of Qutest at all levels of upsampling I tried (most of them) using HQP. No clicks and pops heard via SPDIF.

  • This one is the big discovery: Clicks and pops DO NOT occur on USB input of Qutest at the max level of upsampling (768khz) using Roon native upsampling.

  • Using HQP and upsampling to 768khz into USB input of Qutest I quickly get white noise in 1 speaker.

  • I have played 768khz upsampled material via Roon upsampling all day into the USB input of the Qutest and had no problems - no white noise, no clicks or pops

  • I wondered on my roon core / HQP machine (Intel j4205 wtih 8GB ram) was overloaded so I looked at top to find the CPU usage:

    • in HQP Clicks were happening a lot on HQP with poly-sinc-long-lp. Upsampling to 705khz - here CPU load was 42%. This is 42% of 1 core and the CPU has 4 cores. Load varies with other filters (higher and lower than this) but clicks and pops occur sooner or later in all the ones I remember trying.

    • Roon upsampling to 768khz does not cause clicks. CPU load = 29-30%

  • HQP takes 5GIB (~60%) of memory. Roon takes 15%

  • All tests above were PCM - PCM

I think this is now a question for HQP forum so I am moving the question over there. Thanks for the replies so far. I am glad there is not a hardware problem and it is interesting to see the difference software can make!

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