The Topping D90 was the first commercial DAC using AKM's latest and greatest DAC chip, the AK4499. On paper, this DAC chip boasts a THD+N of -124dB, which is lower and better than AKM's previous flagship, the AK4497 at -116dB. Many people believe that DAC technology has been more or less figured out at this point, and that a $100-200 DAC is good enough for most purposes. Therefore, at $700, the Topping D90 is held to a higher standard and must perform flawlessly for it to be a good buy.
Upon release, certain sites measured the D90 and gave it the highest praise. This is exactly why I bought the Topping D90. I thought it would be the last DAC I would ever need to buy. Unfortunately, the Topping D90 stumbled right out of the gate for me.
BROKEN USB IMPLEMENTATION
The first input I tried was USB. Immediately, there were two issues:
- USB noise interference
- Popping sound a few seconds after audio playback stops
This is ridiculous. I have plenty of older DACs that don't exhibit this behavior. It doesn't matter if you set Windows settings to always never have the USB device or port sleep. The driver is ordering the DAC to go to sleep, thus the popping.
Fortunately, my PC tower has optical out. The D90's optical input works perfectly, though you're limited to up to 24-bit/192khz instead of up to 32-bit/768khz. I was happy with using optical input exclusively.
For this review, which came 3 months after purchase, I wanted to see if the issues mentioned above were due to Windows 7's USB audio implementation. So I obtained a Windows 10 test laptop. The issues became worse when I plugged the D90 into the laptop. The audio I heard crackled heavily for 1 minute. And then suddenly, the laptop no longer recognized the D90. I tried plugging it back into my PC tower. Nothing. The D90's USB input had completely died. Fortunately, optical input still worked. Did the USB input break because I had the optical cable plugged in with a music signal at the same time? Who knows, but it still shouldn't have broken like that.
CAN'T DISABLE DISPLAY
One additional point of contention is that the display can't be turned off while the unit is operating. You can change how bright it is, but you can't turn it off completely. This is a major distraction when watching movies in a darkened room. You'll need to cover up the display with some electrical tape. Easy fix, but on a $700 unit, this shouldn't even be an issue.
With the D90's USB input giving me issues from the very beginning, then suddenly failing on me when writing this review, I can say with certainty that you are playing a slot machine when buying this device. It does have a 1-year warranty, but the exorbitant shipping cost for warranty service from North America to China has discouraged me from sending it in. At least I can still use the unit's optical input, and it does work well enough there, so I'll give it an extra half star for that.
Not recommended at all.