Anyone Review Topping D90III Discrete / D90 III Sabre yet ?

[RandomEar]

Приветствую!!
Here is my theory: unlike other DACs, the D90III features a rather complex custom power supply. It is possible that this power supply reacts too sensitively to issues with mains voltage or poor power quality—which would explain why many users in Russia report unsatisfactory performance, including regarding sound quality. I suspect the power supply design is flawed. You might want to try connecting it to a high-quality power source, such as an Accuphase power regenerator.

There could also be interference on the GND line. You could try disconnecting the GND and testing it.

But the unit is already connected to one of those useless "power conditioners". In this case, it happens to be a true isolation transformer which is pretty much the best you could hope for. Adding another conditioner to the condtioned conditioner does not seem useful in any way.

Rule of thumb: AC mains is never the issue unless you have hard evidence that there is something wrong like brown outs causing restarts of devices and similar events. The AC is rectified inside the unit anyway. Since there is an SMPS in the D90III Discrete, you can likely feed it anything from DC to square waves and it will run fine (not guaranteed with all SMPS, but possible with many) - as long as the voltage is within the supported range and stable.

 

[MBO]

I don't mean to be rude, but you're talking nonsense. Did you read my entire message? I know how difficult it is to design an SMPS power supply; I work in this field myself. This is the first Topping power supply I've encountered, so there are a lot of questions... The D90III has a complex power supply with multiple voltage outputs, which is a very odd design choice for a DAC like that. In any case, the DX9 Discrete features a better design. SMPS power supplies can indeed generate interference that directly affects the processor, just like noise components on the ground rail. And I believe Topping made similar design errors regarding the ground layout in the D70.

 

[SoySalsaPicante]

Technically speaking, DX9 Discrete has three separate SMPS inside of it. I don't know if D90 III Discrete (or D70) have more than one.

 

[MBO]

Technically speaking, DX9 Discrete has three separate SMPS inside of it. I don't know if D90 III Discrete (or D70) have more than one.

The D90III features a very compact open-frame power supply with two or three voltage outputs.

 

[RandomEar]

I don't mean to be rude,

You are though. But if you are, you should at least bring forward a convincing argument.

but you're talking nonsense.

Please enlighten us.

Did you read my entire message? I know how difficult it is to design an SMPS power supply; I work in this field myself.

I read your message. You directly linked the DAC "performance" and "sound quality" to mains issues. I have yet to see any evidence for this being the case in any DAC on ASR ever - apart from trivial and clear problems like a ground loop.

You also totally ignored my main point that the DAC is already connected to a power regenerator, filter, conditioner or whatever you would like to call it. So I could reciprocate: Did you read my entire message and those of the fellow member who's DAC failed twice?

Again: How would another conditioner improve anything here, if the AC is already fully regenerated by an isolation transformer?

 

[Joe Bob]

Hi everyone,

I recently got the new Topping D90 III Discrete and noticed an annoying issue. When the DAC is in standby mode, its internal power supply emits a noticeable high-pitched noise / coil whine.

In total silence, it’s quite audible from a few feet away. What’s interesting is that the pitch isn’t perfectly steady — it sounds a bit modulated or "unstable," like the power supply is struggling with the micro-currents in standby. When the device is fully turned on and playing music, the noise disappears (or is completely masked).

I previously had another unit of the same model, and it also had a standby whistle, but that one was a flat, single-frequency tone. This new replacement unit sounds even more modulated and annoying.

I wanted to ask other D90 III Discrete owners here:

1. Do you experience any high-pitched transformer buzz or coil whine when your DAC is in standby?
2. If you do, have you found any way to mitigate it (besides completely cutting the AC power)?

I really love the sound of this DAC, but this standby noise in a quiet room is driving me crazy. Appreciate any feedback or measurements if anyone has investigated this.

Thanks in advance!

I'm late to the party but I'll toss in my experience. I have a D90 III Discrete and haven't had any issues with noise* in the year and a half I've owned it (and across 3 firmware updates). At idle it's silent. However, I did experience what you're describing with my previous D90LE. I sent that back to the dealer who deemed it a defect, and I received credit which I used toward the D90 III Discrete.

I would consider having the dealer take a look at it rather than trying to find solutions for it on your own. It does sound like a manufacturing issue.

* The original firmware it came with (v0.39) had a quiet but audible click when the input stream changed (e.g. track or bitrate changes, etc). This was fixed in the later firmware updates.

 

[MBO]

There are two possibilities:

1. "B-stock" units are explicitly being shipped to Russia. I have frequently read reports from Russia about the D90III having strange issues, including sound quality problems.

2. The poor quality of the power grid in Russia—that is no secret either. The only solution here is very expensive power conditioning equipment.

 

[Le_Passager]

Hi everyone.

I am facing a critical, recurring issue with the new Topping D90 III Discrete. This is my second unit of the exact same model, and it has just experienced the identical catastrophic failure as the first one.

The setup configuration:The DAC is connected via USB to a PC (source), via XLR to a Topping A90 Discrete pre-amp, and utilizes the 12V trigger to wake up the pre-amp and power amps. Everything is powered through a high-quality AC power conditioner (power delivery is stable and clean).

How the issue occurs:I typically turn off the AC power switch on my power conditioner when the system is not in use. When I turn the AC power switch back on, the DAC receives power, but instead of booting into its normal standby state or powering on, the screen remains completely blank.

The unit becomes entirely unresponsive to the remote or the front panel button. The only sign of life is a faint high-pitched coil whine from the internal power supply. When connected to a PC via USB, the system detects the device exclusively as being in DFU (Device Firmware Update) mode.

Key points:

• This is a brand new replacement unit. The first unit failed in the exact same manner (permanently bricked into DFU mode upon AC power-on).
• I used a previous generation Topping DAC in this exact same operational routine for a year without a single issue.
• Reflashing the firmware via the Topping DFU tool does not restore the device to operational status.

Is this a known hardware/firmware bug related to the micro-controller initialization during AC power sequencing on the D90 III Discrete? I would highly appreciate any advice, official feedback from Topping engineers, or experiences from other owners who cycle their AC power.

Thank you.

P.s. I can't believe it, they wrote above that this coil whine sound in standby mode is a sign of a faulty device, but it turns out that this is already the second faulty device in a row!

UPD: After successfull reflashing a firmware to V0.57 i see "MCU no fw". Then "upgrading...". And then - totally blank display and coil whine sound.

UPD_2: After flashing to v0.39, the device consistently shows "MCU no fw." (without next "upgrading...". Well, that's a change, I'm hoping it's a software bug. I've contacted Topping's service center and hope for a response.

UPD_3: https://www.head-fi.org/threads/topping-d90se-updates-to-d90-iii-discrete.974127/post-19102750
A similar problem was described by a Head-Fi.org user, though unfortunately, the post went unanswered. Well, if the device really has such issues simply from being turned on and off, then this will be my last Topping device.

So, I'm back with the final results of the story I previously described. A local authorized service center has completed its inspection of the two Topping D90 III Discrete DACs that failed on me. The official technical conclusion is:
"The diagnostics revealed an unrecoverable hardware failure: damage to the non-volatile memory chip (Flash memory) that stores the device's system firmware. While entering the Device Firmware Update (DFU) service mode is possible, restoring the stock firmware using standard methods is impossible. The root cause of the chip failure is a manufacturing defect."

The diagnostic conclusion was identical for both the first and the second DACs that I went through. The local retail shop kindly provided me with a replacement unit, noting that this specific issue had been logged only within the older batches, whereas the defect has already been resolved by the manufacturer in the newer production runs. However, to be completely honest, I am now hesitant to plug a third consecutive unit into my system, so I will most likely proceed with a full refund.
I don't want this to sound like I'm trying to discredit Topping, but I have made the decision to switch to audio components from another brand that feature linear power supplies (LPS). Since making the switch, everything has worked flawlessly. By the way, the new equipment is running on the exact same electrical network, which hopefully addresses the previous assumptions regarding the power grid quality here in Russia.

Experiencing hardware failures with two brand-new DACs in a row was definitely a bit discouraging. Additionally, in my specific case, there were issues with audible noise from the LA90 Discrete power supplies, which I have also mentioned in the corresponding amplifier thread.
That being said, I still evaluate my overall experience using the D90 III Discrete, A90 Discrete, and LA90 Discrete stack as positive, and I can confidently recommend it to others as a highly capable and convenient desktop setup for environments where the ambient noise floor isn't as strictly demanding as mine.