Topping D90 USB input fail

[Oily Rag]

I have, no, had, my MacBook Air connected to my D90 dac using the latter's usb input. This worked fine until, for no reason, it stopped working; no sound, not a dickybird.. I have checked the connection with a second MacBook with the same outcome. I have now swapped in an inferior dac using its usb input and everything works fine again so I know the problem lies with the Topping. I'm in the UK and don't want to send the dac back to China for repair under warranty if I can help it. I guess an alternative is to connect to the coaxial input of the dac but do I need some sort of converter to do this and will the sound quality be adversely affected?

Thank you for any advice.

 

[somebodyelse]

It seems the Air wasn't one of the models with an optical output in the headphone port, so you'd need a USB to spdif or toslink adapter. The D90 doesn't support the highest sample rates with these inputs - check the manual for the limits, but probably 192kHz max. I think the D90 was insensitive to jitter on these inputs, so you shouldn't need to go looking for fancy adapters claiming low jitter to have good performance.

I'd be tempted to try it with something that's not a mac in case a problem update has stopped it working on both machines - unlikely, but not entirely unheard of based on reports from mac-using friends. You could also see if there's a MacOS equivalent of the linux diagnostic tools like lsusb to see whether it's just not detected at all, or it's found but something is going wrong talking to it.

 

[Oily Rag]

I hadn't thought of checking it with a PC. I have one I can use for the purpose. Both Macs I've tried 'see' the Topping but just not communicating.
I shall give the PC a try

 

[Oily Rag]

I've now tried a PC and still nothing doing. I've only had the Topping since just before Christmas so i'm not very impressed. Looks like I'm going to have to get an adapter and use the coaxial input.

 

[somebodyelse]

Both Macs I've tried 'see' the Topping but just not communicating.

Curious...Topping may be able to guide you in some more detailed diagnostics. It can't hurt to ask. Perhaps @JohnYang1997 can direct you to the right person?

 

[Doodski]

I'm trying to work out if the many reports of Topping failures here do not indicate a quality control problem and are merely a function of Topping's popularity among ASR posters.

When I used to provide warranty service for Alpine car audio they ran a 0.015% warranty rate for actual warranty faults. That was considered exceptionally good. That would equate to 150 service units out of 10,000 units. Considering the hit rate of ASR when people do web searches for Topping I would hazard a guess that the failure rate is not as high as some might think.

 

[somebodyelse]

You'd need to ask a stockist like Audiophonics how the failure rate compares with other similar products.

 

[Dialectic]

You'd need to ask a stockist like Audiophonics how the failure rate compares with other similar products.

They won't tell.

 

[somebodyelse]

They won't tell.

I though t that went without saying, so I didn't bother. Can't go having informed customers - that might lead to a competitive marketplace.

 

[Oily Rag]

Curious...Topping may be able to guide you in some more detailed diagnostics. It can't hurt to ask. Perhaps @JohnYang1997 can direct you to the right person?

Thank you for your suggestion. I have messaged John Yang and await his response.

 

[trl]

Any reply from John? Any change in DAC's behaviour?

 

[restorer-john]

When I used to provide warranty service for Alpine car audio they ran a 0.015% warranty rate for actual warranty faults. That was considered exceptionally good. That would equate to 150 service units out of 10,000 units.

150 in 10,000 is 1.5%...
0.015% would be 15 failed units out of 10,000 and I do not believe that number is possible.

 

[Doodski]

150 in 10,000 is 1.5%...
0.015% would be 15 failed units out of 10,000 and I do not believe that number is possible.

OOPs did the math in my head and obviously got a "E" on that test Seriously though @restorer-john servicing Alpine was like the lonely Maytag repairman. The stuff rarely came in when in-warranty. We serviced a lot of tape head units out of warranty and very very rarely there would be fried output transistors in a power amp. The stuff is built like a tank.

 

[restorer-john]

The stuff is built like a tank.

Alpine was beautifully made, the tape decks (car and home-luxman) were a work of art. As for the auto power amps- they were really nice. I have a few MOSFET car units I picked up years ago at the recyclers for a few dollars each and they are full of Toshiba MOSFETs for the outputs.

I just loved their signature backlit perspex soft green buttons and lights.

 

[Doodski]

Alpine was beautifully made, the tape decks (car and home-luxman) were a work of art. As for the auto power amps- they were really nice. I have a few MOSFET car units I picked up years ago at the recyclers for a few dollars each and they are full of Toshiba MOSFETs for the outputs.

I just loved their signature backlit perspex soft green buttons and lights.

The first few Alpine car audio units I worked on I near injured my wrist the screws where so tight and I was not ready for it. The first power amp I had my soldering iron stuck to the PCB because the iron needed more heat than it could provide. So I had to call in my workmate with a 2nd soldering iron to melt me loose. Yes, the backlighting and quality of the lamps was exemplary and the micro switches lasted way longer than Sony or Clarion car audio stuff. I loved working on Alpine gear.

EDIT: I looked forward to seeing what mechantronics and electronics tricks Alpine had up their sleeve when working on all the gear.

 

[Oily Rag]

Any reply from John? Any change in DAC's behaviour?

Yes there was a reply. John advised I should send it back to their Service Centre for investigation. I considered the 'transaction cost' of that to be prohibitive so I bought a Topping D10 as a converter and now use the coaxial input....

 

[trl]

I considered the 'transaction cost' of that to be prohibitive so I bought a Topping D10 as a converter and now use the coaxial input....

Sorry to hear that. However, at least it works now.

 

[trl]

BTW, you might open up the device and take it to some GMS/electronics center down town and ask them nicely to inspect the back of the PCB on their microscope. Maybe there are some cold-joints on the USB plug. What do you think?

 

[Oily Rag]

BTW, you might open up the device and take it to some GMS/electronics center down town and ask them nicely to inspect the back of the PCB on their microscope. Maybe there are some cold-joints on the USB plug. What do you think?

Well, everything is working fine for the time being so I won't disturb it. Thanks for the suggestion though. If it changes, I would look for an electronics Engineer in the Bristol area (UK).

 

[trl]

I'm trying to work out if the many reports of Topping failures here do not indicate a quality control problem and are merely a function of Topping's popularity among ASR posters.

What many failures are you aware of, please? I'm only aware of the above issue and this one too https://www.head-fi.org/threads/topping-d90.926531/page-2. I've read about others having similar problems, but after swapping the USB cable issue went away.

However, I've myself encountered an odd issue two days ago when I was listening few TIDAL Master songs via Roon interface: sound started to become distorted after about 10 minutes of playback. I power cycled the D90 MQA unit and everything was perfect after that. I've no idea what went wrong there and I can't replicate the issue, as I have no Roon and no Tidal subscription (I've used a friend's subscriptions just to test the MQA features of D90 MQA unit).