SMSL SU-6 crackling sound issue

[Nick_L]

Dear all,

sorry I am not sure if this is the right forum. So please apologize if I should find another forum/section.
A couple of days ago I identified a crackling sound issue with my SMSL SU-6 DAC which is a couple of months old only.

The issue comes and goes and it is very difficult to predict when it will happy. Switching from one input to the next is sometimes solving the problem - sometimes is does not. But I can clearly hear that it appears more and more often. I will contact Shenzenaudio and ask for a repair and I am just curious if this is a known issue. I attach an mp3 file for demonstration.

The file gives you example about the noise without any "load" on the DAC. When I play audio in parallel, it will stutter the music.

Thanks for your thoughts
Nick

 

[rentaclaus]

More infomation is needed.

First: How is the DAC attached ? USB, Tos-Link, Coaxial, ...
Second: what device is used for playing ? Computer, smartphone ...
Third: in case of Computer or Smartphone what OS ? Windows, Linux, MacOS, Android ...
Fourth: what files are played 16Bit PCM, 256 DSD .... ?

 

[Nick_L]

More infomation is needed.

First: How is the DAC attached ? USB, Tos-Link, Coaxial, ...
Second: what device is used for playing ? Computer, smartphone ...
Third: in case of Computer or Smartphone what OS ? Windows, Linux, MacOS, Android ...
Fourth: what files are played 16Bit PCM, 256 DSD .... ?

Hi rentaclaus,

I use in my primary setup a raspberry PI (#2) running piCorePlayer/Linux (#3) as a network streamer connected to the SMSL DAC via USB (#1) and feeding an integrated amplifier. This setup was working fine for two months. I also have these sound issues when I connect my old CD player via Coaxial.

Suddenly these issues showed up and I have the same issue using my alternative setup:

Latest Windows 11 PC (#2) using the SMSL DAC for outbound audio via USB. I used different cables of course for each setup.

So far I only played 16 Bit 44.1KHz and 48KHz PCM audio (#4). What is really difficult is the fact that the error takes some time - so it can be that you can play for 10min without any issues and then it starts crackling and cracking.

 

[rentaclaus]

Please check if the crackling is related to power savings.

An advice for linux can be found here, you need to adopt it to your raspberry.
https://www.audiosciencereview.com/.../how-to-disable-power-savings-in-linux.40511/

somewhere buried in audiosciencereview postings you can also find a detailed advice for windows.

As others report a change in crackling behaviour of raspberry too, this might be a issue after an update.

 

[xeizo]

Windows 11 has some serious power saving issues with USB audio, basically you have disable Power Management for each and every USB hub that appears in Device Manager if you want pristine audio without glitches. Raspberry Pi may have similar issues.

I guess USB audio as a whole was designed before power saving was a thing ....

 

[Nick_L]

Thanks for your ideas and suggestions. I personally don't think that this is related with the power settings on Linux/Windows. The raspberry pi (piCoreplayer) hasn't been updated in the last months and the issue is also there if I connect just a plain CD player. I believe the DAC is somehow damaged - something is broken - and I will send it back to Shenzenaudio.

I will keep you posted about the outcome.

Nick

 

[rentaclaus]

I've discovered the more hidden entry, how to disable powersavings in xmos-drivers for windows ...

see

XMOS driver settings for no cutoff/delay

I was contemplating on creating a "tutorial" of sorts for all XMOS drivers on devices that have a cutoff -- latency between the start of a sound and the dac "reacting" and actually playing said sound... So here it is: XMOS drivers use a control panel not unlike this: Usually the "Options"...

www.audiosciencereview.com

 

[rentaclaus]

the issue is also there if I connect just a plain CD player. I believe the DAC is somehow damaged - something is broken - and I will send it back to Shenzenaudio.

Could be a thermic problem with soldering. ... and I don't recommend to try by yourself to resolder the chip.
But yes seems like it is broken and best would be to exchange it.

 

[pufferfish]

I have exactly the same issue and it's not computer or speaker dependent.

 

[pufferfish]

What is especially puzzling is that it 30 seconds for the crackling to start if it has been off for a while. If your turn it on and off, it appears more quickly. My house is 60 degrees F now. Anyone have any ideas? I'm not sure it's that feasible to send it back.

 

[rentaclaus]

If your turn it on and off, it appears more quickly.

Sounds like a thermic problem... You can make a very simple test. Take a cold cooling-pack and place it on the device. If this exceeds the time until crackling apears, you can be shure it's a thermic problem and you should exchance the device.

 

[MRC01]

At the risk of turning this into an SMSL SU-6 problems thread, my SU-6 which has been reliable for just over a year, just developed a problem. I was listening yesterday and it didn't sound quite right. Too subtle to pin down, so I measured it. It has developed THD at -55 to -60 dB, all 2nd harmonic. It used to measure clean (THD below 90 dB which is what my sound card measures in loopback mode). I measured the sound card again in loopback, sure enough, it's still clean. But when I put the SU-6 into the circuit and measure its outputs, I get elevated 2H between -55 and -60 dB. Pictures worth 100 words, so...

Sound card in loopback mode:

Now measuring SU-6 output:

Over the past year I've always used my sound card SPDIF coax output to the SU-6 and it used to measure clean. Just for fun I tested it using USB output from PC to SU-6, same results as above. I also put the JDS Atom amp in the loopback, measures clean. It's definitely an SU-6 problem.

So something failed in the SU-6. As 2nd harmonic can be caused by asymmetry between the + and - sides of the waveform, I'm guessing it might be a bad capacitor, or something in the I->V conversion from the DAC chip output. Whatever the problem is, I've emailed SMSL. FYI, the SMSL website says their email contact is "[email protected]". We'll see if their support is better than their durability / longevity.

 

[AnalogSteph]

So something failed in the SU-6. As 2nd harmonic can be caused by asymmetry between the + and - sides of the waveform, I'm guessing it might be a bad capacitor, or something in the I->V conversion from the DAC chip output.

I'm thinking something more along the lines of a bad solder joint, e.g. on some opamp's V+. Though as flat as H2(f) is, the problem could also be directly in the signal path. These are the kinds of small problems that bring down a complex system. 10 second fix after 1 hour of troubleshooting.

If you feel brave enough to take a look inside, see whether you can't subject the board to the classic screwdriver handle tap test in suspect areas and rerun the measurement to see whether anything has changed. Not sure how much a magnifying glass would reveal... maybe some good macro shots would help some of us assess general soldering quality. It's not necessarily easy to spot with this lead-free stuff.

 

[MRC01]

Sadly, it says 1 year warranty and it's just over 1 year old. I'll wait to see if they do a courtesy warranty replacement. If not, then I'll open it up and take a look. I've done some DIY stuff before and built my own gear, so if it's something simple I can probably fix it myself.

 

[MRC01]

A quick peek inside shows it's hard to fully disassemble, especially around the power supply & switch and the output jacks. And it looks like tiny SMD components which I'm too ham-fisted to deal with.

I have gotten in touch with SMSL but English isn't their 1st language so it's a simple 1 line email each day. Imagine the frustration level of playing 20 questions by mail. Yet worth it, if it leads to a good outcome.

I like this SU-6 so I hope they replace it for me even though it's a few days out of warranty. That would be great. But I'm not holding my breath, as I can see from reviews on Amazon that they have more than their fair share of failures with poor warranty support. In that case it's a $170 lesson in buying American for quality and relatively local responsive support.

 

[MRC01]

... I will contact Shenzenaudio and ask for a repair ...

Public service announcement: the SMSL support email is "[email protected]".

 

[MRC01]

I'm thinking something more along the lines of a bad solder joint, e.g. on some opamp's V+. Though as flat as H2(f) is, the problem could also be directly in the signal path. These are the kinds of small problems that bring down a complex system. 10 second fix after 1 hour of troubleshooting.

If you feel brave enough to take a look inside, see whether you can't subject the board to the classic screwdriver handle tap test in suspect areas and rerun the measurement to see whether anything has changed. Not sure how much a magnifying glass would reveal... maybe some good macro shots would help some of us assess general soldering quality. It's not necessarily easy to spot with this lead-free stuff.

To get the board out I had to desolder the power connections. The board looks clean, nothing obvious that I can see, inspecting it with my magnifying headset. Any particular areas I should look at closely? SMSL factory support is non-existent (they'll email you but they won't actually do anything), so if I can't fix this it's going into the trash.

 

[IAtaman]

Is it the same with the optical in?

 

[rentaclaus]

have a look at this thread, seems like SU9 has the same problem, there's also a solution (ways beyond my capabilities ..)

SMSL SU9-n issue

About one year ago I bought the SU9-n based on Amir's review. I wanted a good quality DAC that had impeccable measurements and the SU9-n ticked all the boxes. The lack of MQA is not an issue. I I do have a TIDAL subscription but I'm ok with CD quality only. After enjoying the DAC for about one...

www.audiosciencereview.com

 

[MRC01]

Yep, the distortion is always there at the same level regardless of input: optical, coax, or USB.