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Soncoz LA-QXD1 Balanced DAC Review

MechEngVic

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yes, two good shielded cables
Were your cables coax cables? If so maybe try regular unshielded RCA's. Your problem IMO must be caused by an electric fluctuation, so a change in resistance of the cables might change the effect of the fluctuation. How about ferrite rings on the power and coax cables?
 

sundbp

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Same problem when the dac is plug on a power bank ! :O

Hi. I am seeing something similar - not coax related, for me it's USB input from my desktop computer. But the same kind of thing. In my home office I have a bunch of electrical equipment, and also a running machine. As I hit start on the running machine and the belt motor starts running the Soncoz DAC becomes unresponsive over USB, and I see this kind of thing in the logs if I try to use it:
Code:
Nov 22 22:01:14 desktop kernel: usb 5-2: USB disconnect, device number 115
Turning off the belt motor and I see:
Code:
Nov 22 22:01:17 desktop kernel: usb 5-2: new high-speed USB device number 116 using xhci_hcd
Nov 22 22:01:17 desktop kernel: usb 5-2: New USB device found, idVendor=152a, idProduct=8826, bcdDevice= 5.01
Nov 22 22:01:17 desktop kernel: usb 5-2: New USB device strings: Mfr=1, Product=3, SerialNumber=0
Nov 22 22:01:17 desktop kernel: usb 5-2: Product: LA-QXD1
Nov 22 22:01:17 desktop kernel: usb 5-2: Manufacturer: SONCOZ
The running machine and the Soncoz are plugged into different sockets, but the sockets are likely on the same mains loop.

Next I tried powering it from a 5V/2.1A 17000 mAh battery. Same effect, the moment the motor starts it disconnects from USB, and when I stop the motor it reconnects.

No other electrical equipment in the room (or on the floor) has any issues whatsoever. I only worked this out as I tried to play some music while going for a run and the 2nd time the music cut out as I started running I got a bit suspicious..

Given the battery test it looks very much like something on the Soncoz side isn't shielded the way it should be so the electromagnetic effect of turning on my running machine is enough to trip it up?

(If I run washing machines, dish washers and similar that are located in different parts of the house (further away, walls, etc) there is no impact.)

I guess next step I could try a different USB cable, but from the thread above that seems unlikely to fruitful. More likely to work is a Faraday shield of some sort :)

What do you say @Ben1987 - anything that comes to mind in terms of EM impact?

Thanks for an otherwise great product!

EDIT: Tried different USB cable, as expected that's not the culprit in itself. I don't have any suitable ferrite rings around so I can't check adding those to power cord easily.

Another piece of info - once my belt motor is on, if I try to restart and reconnect the Soncoz to the machine it seems to not be able to establish a USB connection. Once I hit the stop button on the motor it connects straight away (without need for a restart or reconnecting wires or similar). So it'd seem it's not just an surge when the motor turns on that causes issues but ongoing EM effects of the motor. I'll see if I can work out a Faraday bag to establish if it's an effect on the PCB side or if it's via connected cable(s).
 
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somebodyelse

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It would be interesting to see what the belt motor (or its drive electronics) are emitting. If you've got a USB TV dongle you might be able to use RTL-SDR to look for any obvious frequency spikes or a general increase in noise floor.
 

sundbp

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Good idea. I do have some SDR equipment and will see if can carve out some time to explore later in the week.
 

Lero

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I dont know if this belong to this thread but my soncoz la-qxd1 worked very good for exactly 1 month and....a second ago was burning. Not litterally on fire, but is smells very bad and was hot to touch, of course didn't work at all anymore...im returning it. But how?
 
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porotikos

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oh god. i am starting to worry now... too many reported failures... i am starting to worryabout mine as well...
 

Lero

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oh god. i am starting to worry now... too many reported failures... i am starting to worryabout mine as well...
im so disappointed...at this point im just waiting for the d30pro and a30pro...only possible upgrade now!
 

Ben1987

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Given the battery test it looks very much like something on the Soncoz side isn't shielded the way it should be so the electromagnetic effect of turning on my running machine is enough to trip it up?
Strong EMI is a big concern for electronic devices. For LA-QXd1, strong EMI can cause the XMOS chip to reset (and not connect to USB). As far as possible away from the use of strong electromagnetic interference environment is currently the most effective means to avoid this problem.We are also testing what level of ELECTROMAGNETIC interference directly causes LA-QXD1 to fail.Thank you for sharing your test case.
 

Ben1987

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Not litterally on fire, but is smells very bad and was hot to touch, of course didn't work at all anymore...im returning it. But how?
im so disappointed...at this point im just waiting for the d30pro and a30pro...only possible upgrade now!

After a period of research and discovery of the specific causes of equipment failure or damage, we generally determined that strong static electricity is the culprit.Especially in some dry air in the region will appear the probability of failure will be higher.

We tested it in different areas:
In northern China, such as Beijing, the air is dry and static is strong.
In southern China, such as Shenzhen, the air is humid and there is almost no static electricity.

Running LA-QXD1 alone for long periods of time means that LA-QXD1 is not in contact with any other devices, especially metal devices, and LA-QXD1 in this case can be understood as an electrostatic collector. In dry air areas, LA-QXD1 runs for a period of time (ranging from a few days to a dozen days), if there is human contact (hand), it may lead to high voltage electrostatic spark, thereby damaging the unit. This is one of the mechanisms by which we found the unit to be damaged.

In other cases, LA-QXD1 was run without corresponding damage. There are several effective ways to avoid this problem:
1) If it is an already purchased user and the local air drying has high static electricity, we suggest that LA-QXD1 contact the metal surface of other surrounding equipment to help prevent static electricity;
2) For newly purchased users, we have optimized and tested the ex-factory PCBA and the casing for a long time, but nothing similar happened, which proves that my optimization method is effective and subsequent shipped machines are optimized. Optimized units have no impact on performance and can be safely used.

The above problem has been confusing me, SONCOZ was in South China's Shenzhen, our laboratory test all didn't test the electrostatic problem, until one day my user in Beijing (north China, the air is very dry) suggested that I might be the electrostatic problem.Then we started a series of tests and finally identified the problem and found the optimal solution.

The SONCOZ will always be the company that accepted the user's opinions, optimized the product and promoted the user experience. Thank you for your support.
 

MechEngVic

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Thanks Ben, way to step up and continue testing, this research will no doubt even help other manufacturers. Here in Southern California, the humidity rarely falls below 40%. I leave my LA-QXD1 on 24/7 and have had exactly 0 issues. I am even using it with Pro Tools to listen to playback with no problems, and anyone who mixes music with Pro Tools know how finicky it acts with any output that is not an interface. The LA-QXD1 is quickly becoming one of my all time favorite components!
 

sundbp

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Strong EMI is a big concern for electronic devices. For LA-QXd1, strong EMI can cause the XMOS chip to reset (and not connect to USB). As far as possible away from the use of strong electromagnetic interference environment is currently the most effective means to avoid this problem.We are also testing what level of ELECTROMAGNETIC interference directly causes LA-QXD1 to fail.Thank you for sharing your test case.

Thanks for getting back to us @Ben1987. Given my other assortment of electronic equipment in this room that don't show any issues I reckon there are good mitigation techniques you can apply in a v2 to avoid the issue. In my case it's not a very big deal - not playing music via LA-QXD1 when I'm running isn't the end of the world :) Echoing @MechEngVic I've got zero other issues so I'm not an unhappy customer.

I'll probably end up ordering a cheap Faraday bag to perform a test with - my hunch is that'll work fine. The unit runs cool so operating in that environment for some periods of time should be fine - I'm not a marathon runner :)
 

Lero

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After a period of research and discovery of the specific causes of equipment failure or damage, we generally determined that strong static electricity is the culprit.Especially in some dry air in the region will appear the probability of failure will be higher.

We tested it in different areas:
In northern China, such as Beijing, the air is dry and static is strong.
In southern China, such as Shenzhen, the air is humid and there is almost no static electricity.

Running LA-QXD1 alone for long periods of time means that LA-QXD1 is not in contact with any other devices, especially metal devices, and LA-QXD1 in this case can be understood as an electrostatic collector. In dry air areas, LA-QXD1 runs for a period of time (ranging from a few days to a dozen days), if there is human contact (hand), it may lead to high voltage electrostatic spark, thereby damaging the unit. This is one of the mechanisms by which we found the unit to be damaged.

In other cases, LA-QXD1 was run without corresponding damage. There are several effective ways to avoid this problem:
1) If it is an already purchased user and the local air drying has high static electricity, we suggest that LA-QXD1 contact the metal surface of other surrounding equipment to help prevent static electricity;
2) For newly purchased users, we have optimized and tested the ex-factory PCBA and the casing for a long time, but nothing similar happened, which proves that my optimization method is effective and subsequent shipped machines are optimized. Optimized units have no impact on performance and can be safely used.

The above problem has been confusing me, SONCOZ was in South China's Shenzhen, our laboratory test all didn't test the electrostatic problem, until one day my user in Beijing (north China, the air is very dry) suggested that I might be the electrostatic problem.Then we started a series of tests and finally identified the problem and found the optimal solution.

The SONCOZ will always be the company that accepted the user's opinions, optimized the product and promoted the user experience. Thank you for your support.
Just to be helpful for your research, la-qxd1 was usb powered and it was running no longer than 60 seconds when i plugged in headphones in the amp. Sound was "confused" and only in one channel, 2 or 3 minute later while figuring out what was wrong i started to smell burned components, in less then 5 minute i touched the dac an was hot to touch.
My room is not hot or something and i can tell its more than 50% humidity.
Audio source optical, power source original cable in usb port.
 

alekksander

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I dont know if this belong to this thread but my soncoz la-qxd1 worked very good for exactly 1 month and....a second ago was burning. Not litterally on fire, but is smells very bad and was hot to touch, of course didn't work at all anymore...im returning it. But how?
did You get any answer about the return? i just bought mine, it should arrive next week and now i'm afraid it's gonna happen to me as well. was Your power source a reliable device?
In other cases, LA-QXD1 was run without corresponding damage. There are several effective ways to avoid this problem:
1) If it is an already purchased user and the local air drying has high static electricity, we suggest that LA-QXD1 contact the metal surface of other surrounding equipment to help prevent static electricity;
2) For newly purchased users, we have optimized and tested the ex-factory PCBA and the casing for a long time, but nothing similar happened, which proves that my optimization method is effective and subsequent shipped machines are optimized. Optimized units have no impact on performance and can be safely used.
could You share the fix with us? perhaps we could apply that ourselves. is simple grounding connection gonna prevent this from happening? and if so, how can we ground it? thanks.
 

Lero

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did You get any answer about the return? i just bought mine, it should arrive next week and now i'm afraid it's gonna happen to me as well. was Your power source a reliable device?

could You share the fix with us? perhaps we could apply that ourselves. is simple grounding connection gonna prevent this from happening? and if so, how can we ground it? thanks.
Power source was good, pc usb with cable available in the box. Return throught amazon its my confort in this issue.
 

porotikos

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My soncoz is touching the metal case of a headphone amp i have hopwfully no issues will be faced. In the unfortunate case bad things happen, i hope i am covered by warranty
 

volkl77n

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After reading 35 pages of posts...
It is clear that @Ben1987 has engineered a sonically stellar product, with a good feature set, and at a great price, but it has several issues that all seem to be power related.

1. Voltage and current sensitive. Too high a voltage or, apparently, too low current will damage the unit which I suspect @Lero has experienced.
A well regulated power supply like the iFi iPower seems to be critical for the device to operate safely. @Ben1987 mentioned working on a power supply but has not said when it might be available or if it will be included with the LA-QXD1 going forward.

2. XMOS chip is sensitive to EMI as detailed by @foguy_lucky and @sundbp, though it seems to be a 230v mains issue as I did not read of any U.S. 110v users having this issue. Is this a potential shielding issue?

3. Static discharge damages unit. This shouldn't be an issue no matter the humidity level. Again, @Ben1987 has stated the issue was solved. The question is, are the units currently available on Amazon, HiFiGo, etc, "optimized" or are they still susceptible to the problem? If so, when will the new units ship and how can the user identify a corrected unit?

I would really like to purchase this product, but like many, I'm hesitant with the current issues that are cropping up.
 

sundbp

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Did the experiment of using a Faraday bag. Not a perfect fit, slightly too small to have a perfect closing seal, but a data point nonetheless. Shame it wasn't a bigger bag so I could apply the recommended closing mechanism properly :(

No impact, USB connection knocked out by running machine motor being on. I'll see if I can work out where in the spectrum the EM noise is over the weekend (using SDR device).


IMG_20201126_143855.png
IMG_20201126_143936.png
 
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Mathias

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Is there any measurement of the coax digital output somewhere? (for example: jitter test or jitter spectrum with j-test signal )
 

sundbp

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Did the experiment of using a Faraday bag. Not a perfect fit, slightly too small to have a perfect closing seal, but a data point nonetheless. Shame it wasn't a bigger bag so I could apply the recommended closing mechanism properly :(

No impact, USB connection knocked out by running machine motor being on. I'll see if I can work out where in the spectrum the EM noise is over the weekend (using SDR device).

I didn't have a chance to engage with SDR to check frequencies. I did however have a chance to try a Topping E30 connected in the same room (same location, to same desktop computer) - that DAC has no EM interference issues from the running machine. I think the components going into the USB interface side is pretty similar between the 2 devices - indicating that perhaps there's a pretty simple fix to the issue in a next revision of the PCB.
 
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