Clicking/cracking noise with Pro V3 and DAC Board

DIY Products&Projects DIY Product Questions
1

Hello everyone,

I’m new in the arylic/Up2stream world as I was running a multiroom setup with raspberry pis, but LMS was complicated to run correctly, so I moved to a linkplay system :-).

I just installed a few different boards at home (amp v4, Pro v3, amp 2.1 and amp sub, a wiim mini too).

Regarding the amps, nothing to say, it works flawlessly.
Regarding the Pro V3 without any expansion boards, no issues too. But I wanted to get a better sound and installed DAC boards and an Spdif out board.
On the different Pro V3 equipped with the DAC Board and updated to the latest firmware (4.6.337862.29) , I get lots of cracks, clicks and other noises in my sound. It’s not volume related, and not source related (at least between Spotify, tune in etc). Clicks seems to be more present on the right channel.
It gives a “bad frequency sync” impression, like digital clicks and noises.

I had still one pro v3 not updated (still original firmware out of the box, 4.2.8020.12) and tried this one with the DAC board : far better results.
Pro V3 are powered by an USB power supply (5v 2A). Tried a different one, same result.
They are connecter by ethernet and I removed the wifi antenna.

On another Pro V3 equipped with the Spdif output board and a good external DAC, also updated with the latest firmware, I can also hear those clicks and cracks, but they are less audible. It’s more on some calm songs that you hear the “cracks” (something like a vynil effect, but on all the songs…).

Nothing like this on the Amp V4, and the jack output of the Pro V3 seems also OK.

Any idea if I’m doing something wrong somewhere or is it software/firmware related? Should I channge something with ACP in my setup?

Many thanks!

2

Hi @Brock,

Exactly which connecting cable do you use between the DAC panel and the main panel? It is essential to use the cable provided with the DAC because the other cable is less shielded.

3

Hi Zitev,

Thanks for your fast reaction. I’m using the cable provided with the DAC (the one with only 6 wires instead of seven on the cable coming with the Pro V3).
I saw on soundimport someone explaining we should remove the “unused” spdif wire from the i2s connector because it was a source of noise. I suppose it’s what arylic did by providing this new 6 wire cable. I don’t think it’s more shielded, but at least they remove an unused wire acting like an “noise antenna” :-).

I was also thinking about the cable, but…

4

Try wrapping the cable in aluminum foil.

5

I didn’t explain it in detail, but we kept thinking. Unfiltered cable can cause this type of interference…

6

I have noticed that some of my cables did this. I was able to switch to a cable from another device and it went away.

I hope you get it figured out.

7

Hi,

there may be various HW/SW reasons, but from far, my inputs:

If you use the I2S signals, MCLK, IIS_DATA, BCLK, LRCK, GND, I guess your cable is a flat multi-wire cable right? make sure to use the correct ground reference, i.e pay attention not to create additional ground loops, for example between the different boards power supplies and signal grounds, and if your are using a shield, do not connect both ends of the shielding. The shield should not carry power.

Shielding the whole may help, but this could also be tricky depending on where you connect the shield, and this also increases cross-talk between the wires inside the shield via capacitive coupling.
And most importantly, limit as much as possible the length of the I2S connection bus.

Then, my experience with linkplay A31 based boards (as for Arylic’s devices - the board with the antenna connector) shows that external DACs connected on the I2S bus have far better sound performance if they have their own clock. for ex a board with a dac sabre-es9023 and on-board clock, - which doesn’t exist on the Arylic DAC board, - is working perfectly for my different sets using their own DAC 75MHz Clock, without wiring the MCLK/BCLK from the Arylic board, IIS_DATA, LRCK, being direclty wired to the I2S contacts from the A31 board , as well as GND, VCC , in order to minimize the noise propagation.

The fact that you don’t have this problem with the amp and jack output comes from the fact that the dac/DSP on the Arylic board (MV BP1064) is the source for the MCLK /BCLK fixed clock reference for the Linkplay A31 board with extra short and dedicated signal path. So by design the signal flows are ‘easily’ synchronized. As for the ‘better’ performance using the SPDIF output, I guess it’s due to the fact that the SPDIF format uses a single signal composed of a complexe combination of clock reference, data, channel info, correction code and media information, which implies that the receiving end regenerates ‘clean’ data clocks and syncs, corrects for transmission errors. So if your SPDIF board is ‘clean’ the signal should be fairly good may be with some remaining few glitches though that would be masked with loud sounds, if impedance adaptation is not very good. (SPDIF has higher frequencies and bandwidth usage compared to I2s for the same audio bit rate).

Finally, I also noticed at some point, that there are some incompatibilities between SW versions, as the synchronization protocol between units used for multiroom has been changed to minimize the latency between the boards / channels. In this case you get huge sound dropouts between devices/channels.

Don’t know if this heps,
Cheers
Nobu.

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8

Hi to “all of you” :wink:

First of all, many thanks for your inputs regarding my issue. You got it all right!
I fixed my issues by wrapping the I2S cable with aluminium foil :sweat_smile: .

For the Pro V3 + Dac, I wrapped the whole cable with one piece of foil. No link to any ground or anything else, just a “shield” around the cable and this fixed the issue. The sound is now totally clean.

Regarding the Pro V3 + Spdif output board, wrapping the whole cable with aluminium foil just made it worse… Like if all the mess was stuck in the shield… So I tried to separate the 7 wires from each other and to wrap them in 7 pieces of aluminium foil, again, without linking it to any ground. This made the trick! It now works perfectly without any cracks, clicks, etc.

So the issue is indeed the really bad “shielding” of the I2S cable… Nothing to do with a firmware version or other digital issue… It’s a shame for such a great product, to be stuck with a bad piece of cable… But the fix with some aluminium made it for a few cents!

Let’s play with the multiroom now :wink:
Thanks for your help!

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9

Well done! just for reference, in case of the use of a SPDIF interface, you just need the SPDIF signal + signal Ground (+ VCC & Power ground if not externally provided).
Having the I2S signals also in the same shield will lead to creating noise on the SPDIF signal from the different clocks and I2S signals, hence reducing a lot the S/N ratio. It seems from what you describe that the SPDIF board has indeed poor noise immunity.
SO yes I agree, Arylic shoud provide a cable for SPDIF only ( shielded with 75 Ohm impedance) and one for the I2s connection only.
Anyhow, nice to see that your set-up are working according to your expectations! ENJOY!
Nobu

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10

Great job, thanks for sharing the experience , I’ve picked it as a solution, it would help others who are headache with the same issue. The cable we put inside the box is actually not shielded at all… will discuss to improve it.

11

I’m facing a similar problem with the Pro V3 board, using the SPDIF as input board. I read all the advice above, so I tried to shield the SPDIF signal cable with aluminim, use a shielded cable, tried to connect the shield to the ground, but still I get a lot of cracking noise in the signal. I also tried different ways to bring 3,5 or 5V to the board, thinking this might be the problem.
I notice that the SPDIF board is the only board which is designed to be grounded when screwed to the casing, whereas all other boards (the main Pro V3 and the external DAC) are not grounded (or did I miss something here?). I have a feeling that the grounding is part of the problem, because if I test the SPDIF board without grounding it works better (but still with some cracking noises). But also the distance between the Pro V3 and the SPDIF board is quite large in my case, approx 20 cm.
Did anyone encounter the same problem and can give me some advise how I could solve the problem?
Thanks in advance !

12

Hi. I’m not sure I understand correctly what you are trying to achieve. When you say ‘SPDIF as input board’ do you mean you are using the Arylic ‘SPDIF in board’ as expansion board in order to get the signal from a digital source via SPDIF to be played through the Pro V3? In this case this is different from the previous topic discussed here.

Considering I’m guessing right, the ‘SPDIF in board’ is just a simple interface without any signal processing. The only reason why a DC is needed is for the optical input device/module. My question is then what is the kind of SPDIF source you are using and what kind of SPDIF link do you use? Coaxial or Optical (toslink)?

1- If you are using the coaxial input, you don’t need any power, as my understanding is that the signal is directly fed to the BP1064 chip on the Pro V3. What matters is the signal ground, and input impedance (75ohm). Be careful to use a 75ohm coaxial cable (like a video one) not a regular RCA audio cable, as the SPDIF signal is a complex quite high frequency signal, and the transmission needs to be adapted in terms of impedance to make is ‘decodable’ by the Pro V3 interface. A bad impedance adaptation ‘blurs’ the signal, if you want, making it difficult to use for the digital chip.

2- If you are using the toslink,- which is the best option to avoid ground noise PB, hence cracks - then make sure that the optical cable is not too long and of fair quality, as in this case, the purity and power of the laser signal has to be kept. The benefit of this type of link is that the optical receiving module ‘reshapes’ the signal into a more square digital compatible signal at its output.

Another important factor is the digital sample rate and frequency of your source. Beware, the toslink is limited to 16bits 176.4khz (44.1 X4). But more generally, the native sample rate of the DSP is 44.1kHz/16 bit so oversampling will not help, and the higher the sample rate, the more sensitive to noise will be the set up.

Finally, avoid long wiring between the board and the ProV3. The longer it is the more noise sensitive it will make the whole.

Hope this helps
Cheers N.

13

Dear Nobu,
Thanks for your reply with insight and advise related to the problem.
As a matter of fact, I’m using the SPDIF in expension board sold by Arylic for the Pro V3, which comprises a coax and an optical connector. In my case I’m using the optical (toslink) connector, that’s why I need to feed the board with 3,3 V.
I would also have thought that the signal from the SPDIF board to the Pro V3 have enough amplitude to not generate cracking noises.
Now both the SPDIF board and the Pro V3 use the little Ph2mm connectors, which are not designed for shielded cables. What kind of cable would you recommend to use to connect the SPDIF board to the Pro V3? In my current design, I cannot reduce the length of 20 cm between the SPDIF board and the Pro V3 unfortunately.
What about grounding? The SPDIF board is designed to be grounded to the casing. I tried to ground it or to not ground it using plastic screws and washers. There are less cracking noises when not grounded, but still doesn’t entirely solve the problem.
Have you any advise on the grounding of the Arylic components (Pro V3 and SPDIF input board) so as to avoid ground loops and enhance signal quality?

14

Dear all,
I finally solved the problem by using a shielded cable between the external SPDIF board and the Pro V3, and connecting the shield on the Gnd pin on the SPDIF board and on the Pro V3 board.
I also decided not to connect the ground of the external SPDIF board with the metal casing, because this introduced some noise. So I used a plastic washer and plastic screw to fix the board on the back panel of my casing.
Hope that helps some of you out there :slight_smile:

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