Did you try with a different USB-cable?
I remember having similar crackle-problem with Holo Red - Spring 3 combination, but this happened only with i2s connection (tested with two different high quality HDMi cables). In my comparison, USB connection had better sound quality and I never had any problems with it, so that’s what I used.
fixing your settings mismatch, might help:
Thanks.
I will check the USB connection, I found the fit of my USB cable and the USB socket of the Cyan 2 a bit loose. Will use the one which came with the DAC.
I will also change the settings as suggested above and report back.
Use big connector USB 3 cable
For best mechanical connection
Thanks, haven’t seen that it is an USB 3 cable.
Holo Audio packed an USB 2 cable to the Cyan 2…
Holo included that kind of USB interface, for this cable
Even though the interface runs at USB 2.0 , its a nicer mechanical connection
Ok, thanks.
Maybe the previous owner changed the cable? Will ask him.
No they included stock USB 2.0 cable (even tho they provide USB 3.0 input connector on the DAC itself).
Let’s see if this solve the problem. I doubt it a bit because the crackle always appears just before the start of a new song when resolution is different from the previous song. Why should this happen this way because of a bad connection?
I dont think it is the cable, someone else suggested it.
I thought at the time I would suggest a better mechanical connector, just for general use, since you said current was loose 
I just re-tested alternating sample rates and no issues.
Could be a faulty unit?
Anyway you said you had more testing to do, let’s wait till then
I also have stock HQP settings, normal buffer. No need to increase buffer
Hm, yep let’s wait and see/hear. 
Previous owner did not hear any crackle with this unit (do not uses HQP).
What else I could test?
May be using Roon and RAAT protocol without HQP and see what is going on there…
Yes do that. Try Tidal/Qobuz deskop apps direct to Cyan 2. Eliminate networked audio completely.
Make a queue of alternating sample rates
Lots of things still to try before panic
…or standalone HQPlayer, without Roon… So that you have less things in the chain…
For the new USB cable I have to wait until tomorrow.
So I unplugged the Cyan 2 (because I wanted to know the serial number) and put back everything together as before.
I switched from NAA to RAAT and no crackle, so USB connection do not seem to be the problem.
I updated ropieee XL and switched back to NAA and crackle is back, in PCM and DSD, so is it HQP then?
How about NAA OS?
That is probably a good idea. Have not used NAA OS before so this might need to wait a bit. I am also busy preparing for my trip to Norway at the end of the week.
Even try direct USB connection to your HQPlayer server
No networked audio as I suggested yesterday
Probably is ropieee that is the issue
I could do that for testing but not as a permanent solution. Roon Server/HQPServer is in different room as my headphone listening station.
So NAA OS is my next step.
I think set-up of NAA OS on a RPi4 was just shortly discussed/explained, but I cannot find it (but found the images. This should be the right one “naa-500-raspberrypi4-holored.7z”). So a link to instructions would be great and I can stop bothering this thread.
Thx
You can extract the .img file from the 7-Zip archive. And then write it to a microSD using some disk image writing tool, such as Rufus or balenaEtcher. Then you just boot it up - and that’s it.
Going to a EVGA NU card, what do the Integrator and Conversion options do. Currently, mine are FIR2 and XFi.
