[skasundr]

I’m running into an issue today where there is a very audible hiss if I turn on DSD Bypass. If I turn off DSD Bypass and leave it in pure DAC mode (not preamp mode), there’s no hiss. Not sure why this is happening. Kind of disappointing but I’m also not 100% sure what the advantage or difference is supposed to be with Bypass turned on versus turned off on this DAC anyway if I’m not using Preamp (PEQ doesn’t matter, it can’t be applied to DSD anyway).

I’ve tried switching between Native versus DoP on my software and it makes no difference; there is hiss with Bypass on, and no hiss with Bypass off.

Additionally, the 12V trigger out is not reliable on the DAC. Fortunately I can rely on the 12V trigger out of my L70 preamp, which always works flawlessly.

-Ed

Did you upgrade the firmware? That was the first thing I did, so not sure if it addresses this particular issue, but I did not experience the hiss with DSD Bypass on.

You said Topping described DSD Bypass as a sort of non-oversampling mode. I took what you said to mean that if DSD Bypass it off (which is default), the unit may be upsampling everything to DSD 512, including all PCM and any DSD less than 512, before running it through the PSRM. I think this is what DSD oversampling DACs that convert everything to DSD before analog conversion, like Cen.grand and PS Audio DACs, also do. If DSD Bypass is on, maybe it does not oversample the DSD signal in DAC only mode, but all PCM signals still would have to be converted to DSD to run through the PSRM as by definition it is a 1-bit DAC architecture that can only convert from 1-bit DSD to analog waveform.

I don’t think any of us really knows how this DAC works, and based on Apos/Toppings vague, generalized answers, maybe they are assuming it either is 1) too complex of a technology for us to understand, or 2) they are being secretive to protect their unique intellectual property. Maybe ask Apos/Topping again for a more detailed answer about what DSD Bypass mode does?

 

[skasundr]

Apos had the D90III discrete on sale today for $850

I think Shenzhen Audio also has the same sale but for 7 days.

 

[Astral Abyss]

I’m running into an issue today where there is a very audible hiss if I turn on DSD Bypass. If I turn off DSD Bypass and leave it in pure DAC mode (not preamp mode), there’s no hiss. Not sure why this is happening. Kind of disappointing but I’m also not 100% sure what the advantage or difference is supposed to be with Bypass turned on versus turned off on this DAC anyway if I’m not using Preamp (PEQ doesn’t matter, it can’t be applied to DSD anyway).

I’ve tried switching between Native versus DoP on my software and it makes no difference; there is hiss with Bypass on, and no hiss with Bypass off.

Additionally, the 12V trigger out is not reliable on the DAC. Fortunately I can rely on the 12V trigger out of my L70 preamp, which always works flawlessly.

-Ed

Looks like a firmware update should address your issue with the 12V trigger. This is from the v0.38 changelog.

---------------------------------------------------
D90 III Discrete Firmware
Changelog
---------------------------------------------------
---------------------------------------------------
V0.38 (Oct 30, 2024)
---------------------------------------------------

* New: Output polarity setting
* Fix: Slight pop sound when adjusting volume while muted
* Fix: Volume maxing out upon exiting standby mode

---------------------------------------------------
V0.37 (September 21, 2024)
---------------------------------------------------

* Fixed issue where a brief press of the power button while displaying "see you" upon
shutdown resulted in signal output from the 12V trigger interface.

* Fixed issue where a long press of the power button during power-on led to entering DFU mode.

* Fixed issue where entering DFU mode was not possible when not using USB input.

---------------------------------------------------
---------------------------------------------------
V0.36 (September 20, 2024)
---------------------------------------------------

* Fixed issue with the 12V trigger output interface not functioning.

---------------------------------------------------

 

[Edward Ng]

Looks like a firmware update should address your issue with the 12V trigger. This is from the v0.38 changelog.

---------------------------------------------------
D90 III Discrete Firmware
Changelog
---------------------------------------------------
---------------------------------------------------
V0.38 (Oct 30, 2024)
---------------------------------------------------

* New: Output polarity setting
* Fix: Slight pop sound when adjusting volume while muted
* Fix: Volume maxing out upon exiting standby mode

---------------------------------------------------
V0.37 (September 21, 2024)
---------------------------------------------------

* Fixed issue where a brief press of the power button while displaying "see you" upon
shutdown resulted in signal output from the 12V trigger interface.

* Fixed issue where a long press of the power button during power-on led to entering DFU mode.

* Fixed issue where entering DFU mode was not possible when not using USB input.

---------------------------------------------------
---------------------------------------------------
V0.36 (September 20, 2024)
---------------------------------------------------

* Fixed issue with the 12V trigger output interface not functioning.

---------------------------------------------------

Thanks; how do I got about updating the firmware on it? Also, what's DFU?

-Ed

 

[Edward Ng]

Looks like a firmware update should address your issue with the 12V trigger. This is from the v0.38 changelog.

---------------------------------------------------
D90 III Discrete Firmware
Changelog
---------------------------------------------------
---------------------------------------------------
V0.38 (Oct 30, 2024)
---------------------------------------------------

* New: Output polarity setting
* Fix: Slight pop sound when adjusting volume while muted
* Fix: Volume maxing out upon exiting standby mode

---------------------------------------------------
V0.37 (September 21, 2024)
---------------------------------------------------

* Fixed issue where a brief press of the power button while displaying "see you" upon
shutdown resulted in signal output from the 12V trigger interface.

* Fixed issue where a long press of the power button during power-on led to entering DFU mode.

* Fixed issue where entering DFU mode was not possible when not using USB input.

---------------------------------------------------
---------------------------------------------------
V0.36 (September 20, 2024)
---------------------------------------------------

* Fixed issue with the 12V trigger output interface not functioning.

---------------------------------------------------

Thanks! I updated it and the 12V trigger works perfectly now. Unfortunately, the DSD Bypass on still creates hiss.

-Ed

 

[Edward Ng]

Did you upgrade the firmware? That was the first thing I did, so not sure if it addresses this particular issue, but I did not experience the hiss with DSD Bypass on.

You said Topping described DSD Bypass as a sort of non-oversampling mode. I took what you said to mean that if DSD Bypass it off (which is default), the unit may be upsampling everything to DSD 512, including all PCM and any DSD less than 512, before running it through the PSRM. I think this is what DSD oversampling DACs that convert everything to DSD before analog conversion, like Cen.grand and PS Audio DACs, also do. If DSD Bypass is on, maybe it does not oversample the DSD signal in DAC only mode, but all PCM signals still would have to be converted to DSD to run through the PSRM as by definition it is a 1-bit DAC architecture that can only convert from 1-bit DSD to analog waveform.

I don’t think any of us really knows how this DAC works, and based on Apos/Toppings vague, generalized answers, maybe they are assuming it either is 1) too complex of a technology for us to understand, or 2) they are being secretive to protect their unique intellectual property. Maybe ask Apos/Topping again for a more detailed answer about what DSD Bypass mode does?

I did ask Apos to check with Topping on what DSD Bypass does, exactly, and am awaiting their response.

In the mean time, I have switched to Pre mode on the D90 II Discrete so as to minimize components in the signal chain as well as cut down on wiring and clutter. It's great having one (bluetooth) remote (that does not need to be aimed like a sniper), and I don't have to listen to the clicking relays on the L70 when adjusting volume. Before the firmware update, this was not practical. Sort of strange to see the 12V trigger tie into firmware/software, I would've thought they would have engineered it to be a pure hardware solution, but I guess not. Like modern cars where even the head/taillamps are wired into the car's computer bus.

-Ed

 

[Lexington99]

I did ask Apos to check with Topping on what DSD Bypass does, exactly, and am awaiting their response.

In the mean time, I have switched to Pre mode on the D90 II Discrete so as to minimize components in the signal chain as well as cut down on wiring and clutter. It's great having one (bluetooth) remote (that does not need to be aimed like a sniper), and I don't have to listen to the clicking relays on the L70 when adjusting volume. Before the firmware update, this was not practical. Sort of strange to see the 12V trigger tie into firmware/software, I would've thought they would have engineered it to be a pure hardware solution, but I guess not. Like modern cars where even the head/taillamps are wired into the car's computer bus.

-Ed

Built-In Preamp mode in DACs always degrades the sound. Both in theory and in practice. There's greater performance to be had with a full 100% digital signal from the DAC into an analogue preamp.

You're not getting better sound reducing components by cutting out a proper preamp, is my submission.

 

[Chardonnay]

I have placed a D90 III Discrete on back-order here on Australia. Buying from local supplier for closer warranty support. One supplier offered early November stock while the second stated early December. Went with the possibly wildly misleading November stock!
I will be replacing a E70 Velvet. The DAC will drive a Pre90 with input extender with ROON as the music source. I plan to have both DACs active at once and hope to switch between either to see if I can hear a difference. I really hope I can as the new DAC is the equal of a large number of bottles of wine!

 

[fidgeraldo]

Looks cool. But it's not for me

Why?

Cheers!

 

[Edward Ng]

Apos got back to me with a response from Topping requesting details on my testing with DSD Bypass On and asked for a video of it so I recorded one to show them the hiss with Bypass On and lack of hiss with Bypass Off. Apos didn’t provide any response on exactly what DSD Bypass is supposed to do on this DAC so I reiterated the question when I sent over everything Topping was asking for.

-Ed

 

[Edward Ng]

I have both, and I think it is definitely an upgrade!

Now owning both, I must admit I concur. The D90 III Discrete simply is more transparent, more realistic in presentation. The sound is more effortlessly natural than even the already impressive E70 Velvet.

-Ed

 

[tooape]

My Bifrost 2 just died... I was a big fan of the musicality and timbre there, I'm also big on the RU7... Is this a viable alternative to the BF2?

 

[rickmcinnis]

I bought two of the Discretes in September. I asked if they would give me the discount they are offering and they told me I bought them too long ago.

My favorite part was including the two weeks I waited for them to arrive as time I had possession of them.

Not to take away from the goodness of the DAC but I know I will not buy from APOS in the future.

But for those who can take advantage of this I would say "take advantage of this price"!

 

[Lexington99]

My Bifrost 2 just died... I was a big fan of the musicality and timbre there, I'm also big on the RU7... Is this a viable alternative to the BF2?

Having owned Bifrost 2 - it's almost entirely certain that it is much inferior to this Topping D90 III Discrete. If you like the Ru7 signature, which is a 1-bit DAC, you'll surely love this Topping. Ru7 rocks.

 

[Astral Abyss]

Having owned Bifrost 2 - it's almost entirely certain that it is much inferior to this Topping D90 III Discrete. If you like the Ru7 signature, which is a 1-bit DAC, you'll surely love this Topping. Ru7 rocks.

I agree. It's an impressive DAC. Very smooth but clear. Takes a few minutes for my ears to adjust to the softness of the sound. If you want an example of what I mean, take an old CD with a high dynamic range and listen to it after a newer "remastered" version. At first, it sounds quieter and less meaty, until you listen for a bit and turn up the volume and realize you're hearing way more of the music and everything sounds less distorted.