Review and Measurements of Topping DX7s DAC and Headphone Amp

[FunctionalDoc]

My Dx7 shipped on Tuesday and is on its way . So I am glad that Aoshida is coming through with my order.
Feel like quite great DAC/Amp for $339.

 

[gab]

I too pulled the trigger on a DX7 from Aoshida last week.
Looking forward to receiving it.

gab

 

[chungjun]

My Dx7 shipped on Tuesday and is on its way . So I am glad that Aoshida is coming through with my order.
Feel like quite great DAC/Amp for $339.

FunctionalDoc, did Aoshida send the DX7 (with remote) or DX7s?

Saw your post here... that they did a "switch"?
https://audiosciencereview.com/forum/index.php?posts/74232/

 

[FunctionalDoc]

No they sent me the DX7S instead. They have responded and say there was a remote in the box and I just notified there wasn't a remote in the box.

Will ses how they handle this.

 

[Stump909]

I asked Topping if the volume control is lossless and here is the answer I got: "Volume control of DX7s is not lossless because it is based on ES9038Q2M's control. So if you need better performance, you need to set to highest volume. "

@amirm : it would be very nice if you can, when you find some time, repeat distortion and noise measurements on low volumes to see how much it affects sound quality.

So basically, using the balanced output (which drives louder at lower dBs) is worse than the single ended output?

 

[Krunok]

So basically, using the balanced output (which drives louder at lower dBs) is worse than the single ended output?

Why would you say that?

Balanced output is typically used when you need to run longer cables. With short cables (say less than 2m) you won't be able to tell the difference between balanced and single ended output as they will have very similar SNR.

 

[Stump909]

Why would you say that?

Balanced output is typically used when you need to run longer cables. With short cables (say less than 2m) you won't be able to tell the difference between balanced and single ended output as they will have very similar SNR.

Maybe my science is off, and feel free to correct me, but it seems like the DX7's volume control is lossy. The balanced output, compared to the SE, has double the OI and voltage. Apples to apples, achieving the same SPL (Balanced to SE) requires a lower output. Lower Output + Lossy Volume Control = Quality Loss. No?

 

[Krunok]

Maybe my science is off, and feel free to correct me, but it seems like the DX7's volume control is lossy. The balanced output, compared to the SE, has double the OI and voltage. Apples to apples, achieving the same SPL (Balanced to SE) requires a lower output. Lower Output + Lossy Volume Control = Quality Loss. No?

As far as I know DX7s uses variable gain control feature in it's ES9038 DAC chip to control volume. I don't have the documentation but for that chip but I don't think there's any quality loss there apart from pushing the signal level closer to the noise floor. But on the other hand, don't all volume control solution do same that thing?

I believe that difference in SNR between balanced and single ended analog output is more due to the implementation of the output stage and not the DAC chip itself.

 

[mtmercer]

I would be curious to see if balanced outputs have the same THD/IMD than the unbalanced ones.

Two other things I would be curious about:

• Does the other antialiasing filter change the passband shape significantly ?
• How close are the two ES9018q2m synchronized? And does restarting the unit and/or resyncrhonize it to another input sampling rate change that?

That second item would require a specific test mechanism, maybe something like looking at the IR resulting from a sweep recorded with REW from the summed output?

Along the same lines as this question, when the DX7s is used in balanced DAC mode, technically which characteristics cancel and which characteristics compound? I assume the DAC should measure better when measured via the balanced outputs. How much better, I have no idea.

I just received my DX7s yesterday and am thinking it is going to be a keeper as my DAC!

 

[Stump909]

As far as I know DX7s uses variable gain control feature in it's ES9038 DAC chip to control volume. I don't have the documentation but for that chip but I don't think there's any quality loss there apart from pushing the signal level closer to the noise floor. But on the other hand, don't all volume control solution do same that thing?

I believe that difference in SNR between balanced and single ended analog output is more due to the implementation of the output stage and not the DAC chip itself.

So the 32-bit overhead should allow it to be pushed down without impacting dynamics.

What specifically were you inquiring with Topping regarding lossless volume control? Thanks!

 

[Krunok]

I assume the DAC should measure better when measured via the balanced outputs. How much better, I have no idea.

Topping didn't specify that, but look at the specs from a similar product (Matrix Mini-i Pro2) to get the idea of the difference between XLR (balanced) and RCA (single ended). You won't be able to hear that. But, as I said, if you need to run longer cables from DX7s to your amp I absolutely advise using XLR balanced cables as they were invented exclusively for that.

Analog Output
XLR
SNR
＞ -123dB 20Hz-20kHz A-Weighting
THD+N
＜0.0003% at 1kHz A-Weighting
Frequency Response
20Hz-20kHz (+0.01dB/-0.02dB)
Crosstalk
＞-130dB @1kHz
XLR Output
4vrms Fixed at 0 dBFS DAC MODE
0-4vrms Adjustable at 0 dBFS PRE MODE
RCA
SNR
＞ -120dB 20Hz-20kHz A-Weighting
THD+N
＜0.0005% at 1kHz A-Weighting
Frequency Response
20Hz-20kHz (+0.01dB/-0.02dB)
Crosstalk
＞-126dB @1kHz
RCA Output
2vrms Fixed at 0 dBFS DAC MODE
0-2vrms Adjustable at 0 dBFS PRE MODE

 

[Krunok]

What specifically were you inquiring with Topping regarding lossless volume control? Thanks!

I asked them how it is designed and got the answer that they rely on variable gain control within ESS DAC chip. Later I learned that many DAC/preamp designers do that, except for some high end designs which use either passive volume control or a dedicated volume control chip. I don't really think that is necessary as even the cheap DACs like D10 manage to achieve excellent specs in every aspect. Performance of the DX7s is so good that, in my opinion, differences between today's high end devices and DX7s can only be measured via high precision instruments like the one Armin has, but cannot certainly be heard with our ears.

 

[Krunok]

So the 32-bit overhead should allow it to be pushed down without impacting dynamics.

Correct. That is from the perspective of the digital signal dynamics. Analog output signal dynamics is anyhow impacted when you lower the amplitude of your signal, no matter how you do it and in which domain.

 

[amirm]

Maybe my science is off, and feel free to correct me, but it seems like the DX7's volume control is lossy. The balanced output, compared to the SE, has double the OI and voltage. Apples to apples, achieving the same SPL (Balanced to SE) requires a lower output. Lower Output + Lossy Volume Control = Quality Loss. No?

With balanced output, you would normally use a an amplifier with balanced input which likewise expects higher voltage swings. So you don't have to compensate for level differences.

 

[FunctionalDoc]

I am having a problem with DX7S playing Tidal where it stops playing for a few seconds then the screen flashes to USB and the back to display and sound.

I am using Windows 7 64 bit operating system through the USB connection. I also notice when I had the power to the DX7s through my computer backup when sound wasn't playing I had a clicking noise. I went straight to the wall outlet and that noise was gone.

I had to install the DX50 driver to get the DAC to work.

What settings should be using within Tidal ?

What settings in the Topping driver setup ?

I suspect the noise was ground loop issue.

I have a copy of Windows 10 and would I be better off going through aggravation of doing a fresh Windows 10 install to use with this DAC?

I love the way this DAC sounds and drives my 300 ohm ZMF Auteur's nicely.

Aoshida-HIFI Audio Store is giving me the run around about the sending me the DX7s vs the DX7 and that since the DX7s doesn't come with a remote. I pointed out that they need to change there ad since it is misleading. Will update all of you on their resolution. Worst case I will have to purchase a remote in May.

Thanks for your help.

 

[Krunok]

You should be able to use ASIO DX7s driver. If it doesn't work you obviously have some issue with the audio drivers on your computer. Try removing them all, restart the machine and install DX7s driver.

Set USB Streaming Mode to "Safe".

Use Roon to playback from Tidal, that should enable you to configure it properly so you will get a better sound.

 

[FunctionalDoc]

I see on topping's site drivers for Dx50 Windows 7 which is v6F2 revision what I am currently using. I don't have Roon I have Jriver Version 22 on my Windows and Mac Book Pro.

In your opinion is Roon worth the money over Jriver if you are just streaming from 1 computer and a Tidal user?

Thanks.

 

[Krunok]

I see on topping's site drivers for Dx50 Windows 7 which is v6F2 revision what I am currently using. I don't have Roon I have Jriver Version 22 on my Windows and Mac Book Pro.

In your opinion is Roon worth the money over Jriver if you are just streaming from 1 computer and a Tidal user?

Thanks.

No, both of them are good products. So you're using Jriver to stream from Tidal?

 

[Krunok]

It's not a good sign if you can't get Dx7s to work with it's own drivers. As I said, try uninstalling all audio drivers, reboot the comp and install DX7s driver.

 

[gab]

I too pulled the trigger on a DX7 from Aoshida last week.
Looking forward to receiving it.

gab

I got a DX7s from Aoshida instead of the DX7 I ordered. And no remote control was in the box. Suppose I shouldn't complain as its a $499 DAC for $332 (33% discount). I'm sure I'll have to buy the remote separately when they are available again in May.