Review and Measurements of Topping D50 DAC

[gvl]

I was trying to say that RF noise present on the mains may end up on the chassy of the audio equipment through that connection in the electric panel and leak into audio circuits from there.

 

[amirm]

I was trying to say that RF noise present on the mains may end up on the chassy of the audio equipment through that connection in the electric panel and leak into audio circuits from there.

The leakage would travel in the hot and neutral lines because those are closed circuits. The chassis is not a conduction path (indeed US NEC code has a limit on how much or I should say little current can travel over ground wire).

So yes, you can backfeed noise onto mains. Its path to actual analog output of an audio product though, is extremely difficult. For one thing, your audio gear has very low bandwidth. It doesn't want to transmit anything called "RF." There can be demodulation effect and hence the reason in some scenarios people hear AM radios and such on their audio gear but in general, the barriers to RF doing anything to your audio gear is huge.

In my test setup, I have my computer with its switching supply doing whatever it wants, I have an LED dimmer that generates noise, and my analyzer of course is another complex beast powered by the same line. Yet we see incredible performance with noise and distortion down to -115 dB in well designed gear.

 

[rebbiputzmaker]

In my test setup, I have my computer with its switching supply doing whatever it wants, I have an LED dimmer that generates noise, and my analyzer of course is another complex beast powered by the same line. Yet we see incredible performance with noise and distortion down to -115 dB in well designed gear.

With all that pollution your equipment should be wearing a hazmat suit!

Aren't you the least bit curious about what possible effect good isolation may provide? I guess you have never owned an isolation transformer.

 

[amirm]

Aren't you the least bit curious about what possible effect good isolation may provide? I guess you have never owned an isolation transformer.

I have asked you multiple times and you refuse to answer. What is that goodness? How did you measure it? Or confirm it?

As for me, I have one better: I can generate my own AC: the B&K 9801 AC source:

I have used it here on some of my measurements when people like you said power was a problem. Of course it was not and just wasted days and days of time.

It is fine to believe in folklore, but please don't make it my job to go and spend a bunch of time disproving it for you. Bring your own data and if you have none, then please don't keep talking about "good" this and that.

 

[rebbiputzmaker]

I can generate my own AC: the B&K 9801 AC source:

Generating your own, even better.

You keep asking a question that you have already answered for yourself. In your instance, you found no difference. Peoples environments are all different and hence, might have different results. Urban environments may be noisier that rural, etc.

 

[amirm]

You keep asking a question that you have already answered for yourself. In your instance, you found no difference. Peoples environments are all different and hence, might have different results. Urban environments may be noisier that rural, etc.

Another lay intuition in dire need of data to back it. How do you know "urban" environments are more noisy?

 

[rebbiputzmaker]

Another lay intuition in dire need of data to back it. How do you know "urban" environments are more noisy?

OK, there is no such thing as electrical noise anywhere. The grid is silent. Whatever you say. I know engineers that might disagree.

 

[amirm]

OK, there is no such thing as electrical noise anywhere. The grid is silent. Whatever you say. I know engineers that might disagree.

Before I let you change the topic, let's get your answer to the question I asked. You said there was more noise in urban environment. I am asking you how you know that.

 

[gvl]

First part is very true. I have been inside electrical panels more times than I can count and have written extensively on this. Second part is not because the ground bus bar continues to a path to "earth." That can be ground rods in dirt or in the olden days, and I imagine some countries still, to metal water pipes. It is this connection to dirt that causes many audiophiles to assign mystical abilities to get rid of noise which I addressed in my post.

The purpose of that connection to earth is a) to shunt high currents due to lightning and b) to keep the line voltages from floating up. The former is why I suggested the best place for a surge protection is at the main meter where the impedance to ground is the lowest.

Equipment ground is a double edged sword, yes it protects against a short between the "hot" wire and a metallic enclosure but in case of a loose neutral on the service side, a relatively common issue, all your grounded devices may have a stimulating potential present on them. Basically you're at the mercy of how well the earth ground is done, and often it's not done all that well. Is this what you mean by 'b'?

 

[amirm]

Is this what you mean by 'b'?

No. When you float a device, the stray capacitance can cause the baseline "zero" to float up. So while the relationship between hot and neutral will remain the same (e.g. 120 volt RMS), the voltage relative to ground can go way up. If something then does have a true ground reference, it will see that high voltage reference and cause damage or erroneous behavior.

 

[rebbiputzmaker]

You said there was more noise in urban environment. I am asking you how you know that.

Because you can feel it.

 

[amirm]

Because you can feel it.

Then you are in the wrong forum.

 

[Ron Texas]

Feel it? When a chemical plant explodes I can feel it, but short of that, no.

 

[Ron Party]

I couldn't resist and I'm very happy I didn't. My D50 arrived today. I replaced my ifi micro idsd. Driver installation was simple. Using ASIO/DoP. Playing DSD256 right now. Works flawlesslessly. No noise like one (some?) reported earlier in this thread. I actually like the volume control... 0.5db adjustments is easy, particularly for my office. This was money well spent. This prog rocker gives it two thumbs up.

 

[amirm]

Most excellent. Thanks for the feedback Ron.

 

[Toku]

I couldn't resist and I'm very happy I didn't. My D50 arrived today. I replaced my ifi micro idsd. Driver installation was simple. Using ASIO/DoP. Playing DSD256 right now. Works flawlesslessly. No noise like one (some?) reported earlier in this thread. I actually like the volume control... 0.5db adjustments is easy, particularly for my office. This was money well spent. This prog rocker gives it two thumbs up.

Congratulations on arrival of D50 successfully. I think the sound from D50 is wonderful. The D50 noise problem I reported earlier occurs when playing in ASIO / Naitive mode. I reported this problem to Topping. They also acknowledged the problem. So I am using it in ASIO / Dop mode like you.
There are other problems as well. If you play music of PCM 384 kHz after playing music other than PCM 384 KHz, you will get big pop noise at the beginning of the song. These problems also apply to DX 7s. The Topping staff says that there is a problem with the driver software supplied from XMOS. And they said that want to improve by updating the driver software nearby

 

[Ron Party]

Hi Toku.

Thanks for the info. Please keep me (us) updated about the driver software update(s)

 

[Lon]

Thanks to Armin and Andreasmaan for their replies to my question about HDMI.
The linked article, and an earlier one by Amir High Performance PC Server Interfaces (Async USB) explained it well. The audio is sandwiched into the video signal.
Now I am curious about USB C. Apparently this interface is faster and has more bandwidth than USB 3.
Will it offer any positive benefits to digital audio?
I am becoming interested in USB noise issues. It appears that getting a clean USB signal to the DAC is not so simple
For instance, driving a Topping D 50 with USB from an older Apple laptop, there is noticeable distortion which is not present when using USB from a newer Mac desktop. Changing the power supply swaps did not change the problem.
Would USB isolation devices help? What about using an ethernet interface to a dedicated USB processor? Is noise isolation the intent of those setups?

 

[Blumlein 88]

Thanks to Armin and Andreasmaan for their replies to my question about HDMI.
The linked article, and an earlier one by Amir High Performance PC Server Interfaces (Async USB) explained it well. The audio is sandwiched into the video signal.
Now I am curious about USB C. Apparently this interface is faster and has more bandwidth than USB 3.
Will it offer any positive benefits to digital audio?
I am becoming interested in USB noise issues. It appears that getting a clean USB signal to the DAC is not so simple
For instance, driving a Topping D 50 with USB from an older Apple laptop, there is noticeable distortion which is not present when using USB from a newer Mac desktop. Changing the power supply swaps did not change the problem.
Would USB isolation devices help? What about using an ethernet interface to a dedicated USB processor? Is noise isolation the intent of those setups?

USB being clean isn't an issue with many maybe most DACs. Look at the thread on the first Modi 2 that Amir measured.
https://www.audiosciencereview.com/forum/index.php?threads/budget-dac-review-schiit-modi-2-99.1649/

That Schiit DAC is very sensitive to USB issues. Over the course of that thread he did several things to show that. Some relatively inexpensive USB hubs helped it plenty. Some USB filtering devices had little or no effect. Most DACs aren't so sensitive though it varies.

I've an ADC that has a tone at - 116 db when connected to my Macbook, but not when connected to other computers. I've a DAC which shows some packet noise from USB, but it is at -128 db. I definitely am not worried by that. Most others don't show anything from the USB.

Unless doing multi-channel USB 3 or type C wouldn't have any advantages from speed. As to whether they are isolated better than USB 2 it likely will depend upon the design quality. I've an ADC/DAC which can be fed via USB 2.0 or Thunderbolt 2. There is not one bit of difference between those two methods of sending digital audio to or from the device in terms of noise. The Thunderbolt has lower latency, but that is a non-issue for signal quality or playback via a DAC.

As for your older Mac laptop, I'd try a powered USB hub and see if that does anything. The Regen did help the Modi 2 quite a bit. With other DACs Amir has used the Regen on it pretty much made no difference or added a tiny little bit of power supply hum.

 

[Hosehead]

Hello, everyone,

This is my first post, but I have been reading this forum's pages for close to six months now, and I have learned a great deal through your posts, so thank you all for sharing your knowledge and your views for the benefit of the rest of us.

With respect to the issue of noise comming from the USB ports, I would like to suggest a few--perhaps very obvious--things to check for:

1- If you are using your TV as your computer monitor and you also have your cable box connected to it, disconnect it and check if the noise goes away.
2- If you are hearing clicks and pops or the sound breaks up whenever you move your pointer across buttons or hyperlinks, lower your sample rate and see if that improves things.

And now, a humble request for help:

After reading Armin's very thorough review of the D50 DAC, I decided to go ahead and get me one. It arrived last week, and I will just say my jaw dropped upon first listen. For many years I was skeptical that a DAC could make such a difference--I am very glad to have been proven wrong. Armin's detailed, science-based review and everyone's comments on the performance of this DAC persuaded me to pony up the $250, and I am glad I did. But my questions is this:

If I open the Audio Midi Setup App on my Mac Mini, I can see the various frequency rates and bit rates the D50 supports, and everything is there except the 44.1 KHz / 16-bit combo; my computer lists only 24-bit and 32-bit resolutions for all frequency rates, but 16 bits is not listed. Is this normal? Do I have a defective D50?