Topping DM7 8-Channel DAC Review

[sarumbear]

Hello @sarumbear and friends,

As for the obvious cons of "balanced" (TRS, XLR) to "unbalanced" (RCA) conversion, you need to carefully read this important educational post (#557 on that thread on DAC8PRO) written by Pavel of OCTO RESEARCH.

It says:

4) Cable with floating pin3 (cold)
Using just one of the signals from the XLR side to interface with RCA is a dirty and cheap solution. We cannot guarantee this will be hum-free (depends on circumstances) or that DAC8's output will be pop-free on turn on/off in this configuration, but it is certainly a better way than the previous one. There will still be an increased distortion compared to interfacing a regular XLR input since you will be picking up the common-mode distortion products that would otherwise be rejected. Because you are only taking half of the signal, you will lose 6dB.

He is not saying you cannot connect balanced to unbalance. On the contrary. He says you can.

If you have an equipment that has unbalanced inputs you will have all the issues that comes with an unbalanced connection. We are not arguing if balanced connection is better than unbalanced. That is outside the scope of argument. We are arguing if you can connect a balanced output to a balanced input.

Yes, you can.

 

[sarumbear]

Depending on the circuit, opposite distortion from the other leg you're no longer summing.

That is a balance vs unbalance connection issue. which is a different argument. The question was not shall I use unbalanced, it was how can I use unbalanced.

 

[dualazmak]

What is not cancelling?

 

[sarumbear]

View attachment 218169

Thank you for the education. However, and as I said already, you are talking about the virtues of balanced. The discussion is not about, I repeat, should I use unbalanced, it was how can I use unbalanced? I hope you can understand the difference... Someone decided to feed the balanced output of this DAC to a unbalanced input of a device. They ask how to do that. That is the question.

 

[dualazmak]

Yes, you can.

Yes, I (we) can; I usually use (only if needed) "pin-3 floated/non-connected" adaptor cable as Pavel suggested, even though losing 6 dB gain and no possible noise cancellation.

As summarized and shared here, I carefully selected amplifiers with "balanced" inputs at least in my multichannel multi-amplifier audio project.

 

[raif71]

Topping needs to pay someone to write up a comprehensive DM7 Guide describing how the 8 channel DAC might best be used. That would open up sales to those that have not explored multi-channel audio via computer and provide testing of configurations that work. Without that sales will be limited. Education will matter if they want this model to sell with volume. Topping will also need to add features in future revisions if they want to expand the market.

Yes a use-case is needed however the internet might be able to provide that. Already there are hints on this thread on how to go about using this DAC. It's like a jigsaw puzzle, taking pieces here and there. Eventually and hopefully the pieces come together to get multiple solutions to this multiple channel DAC.

 

[sarumbear]

Yes, I (we) can; I usually use (only if needed) "pin-3 floated/non-connected" adaptor cable as Pavel suggested, even though losing 6 dB gain and no possible noise cancellation.

I understand why someone needs balanced connections, if the equipment are far away or connected to different power socket. However, the entire Hi-Fi industry is using unbalanced connections for ever. What is the obsession with balanced in Hi-Fi suddenly? Yes, theoretically, you can achieve better performance, but to what extend that matters? Have we suddenly became sensitive to a 6dB noise increase on almost 120dB SINAD devices that best test equipment in the world struggles to measure?

It is nice to know if a device is SOTA and champion their manufacturer but we need to get to grip with reality and put our feet on terraferma.

 

[CedarX]

Hello @sarumbear and friends,

As for the obvious cons of "balanced" (TRS, XLR) to "unbalanced" (RCA) conversion, you need to carefully read this important educational post (#557 on that thread on DAC8PRO) written by Pavel of OCTO RESEARCH.

A good reminder of the risks! Are the risks compounded in the DM7 case? Being an 8-channel DAC, it's conceivable that the DM7 will feed multiple amps with their own PS. Is a ground loop almost a sure case? Can you be certain that no high voltage / current will flow through one of the unbalanced (PCB?) ground connection, smoking an output stage (best case) or the complete DM7 (worse case)?

 

[sarumbear]

A good reminder of the risks! Are the risks compounded in the DM7 case? Being an 8-channel DAC, it's conceivable that the DM7 will feed multiple amps with their own PS. Is a ground loop almost a sure case? Can you be certain that no high voltage / current will flow through one of the unbalanced (PCB?) ground connection, smoking an output stage (best case) or the complete DM7 (worse case)?

What risks? What high voltage? It is an audio signal!

 

[edechamps]

Interesting product. I'm quite tempted as this DAC would solve the issues I have with the borderline output level of my venerable Asus Xonar U7. The price seems a bit steep though - I would have preferred something with a less record-breaking SINAD but cheaper.

I'm also a bit worried that, according to the Topping website, this DAC appears to require a special Windows driver to use the full 8 channels. (My Xonar U7 can do that using the standard Microsoft USB Audio Class 2 driver just fine.) I'd be interested if someone with the product in hand (@amirm maybe?) could confirm if the DAC exposes 8 channels in Windows when using the standard Microsoft USB Audio 2 driver (usbaudio2.sys). I am reluctant to use a potentially dubious third-party driver that might not be supported for long and/or cause random system issues.

By the way @amirm: I would suggest mentioning somewhere in your review that the outputs are balanced - that seems quite important and it's not mentioned anywhere! Maybe even put that in the title as you did in the past for other balanced DAC reviews.

To give a personal answer to the "but what is it useful for FFS" questions that are being spammed in this thread: personally, my only audio source is a Windows PC that I use for music, movies, and gaming. A multichannel USB DAC simply allows me to connect a 5.1 audio system (active Genelec speakers in my case) to my PC. There is no need for anything more sophisticated than a pure DAC because I don't need input switching (there is only one input) nor bass management/calibration (all of that is done in software on the PC using Equalizer APO). In the case of movies, any bitstream decoding to PCM happens in the video player running on the PC so no need for any hardware for that either. I will freely admit that my use case is quite niche but it is a valid one, and this product is definitely useful in that context.

 

[dualazmak]

a 6dB noise increase on almost 120dB SINAD devices

You still have obvious misunderstandings. The 6 dB loss is in the main signal, not the noise level. Possible incidental spike and/or jitter noise would be much much lower level which should be discussed separately from the universal SINAD measurements. I assume you need to learn basics of audio signal handling.

 

[AudioJester]

What risks? What high voltage? It is an audio signal!

At some point we have to give up. If they dont know how to safely get a single ended signal from a balanced output then there is a broader problem. Configuring/setting up a multichannel dac for a multiway active speaker setup is way more risky!
By the way, this would be a good tool for a dba - 2 speakers, 4 subs.

 

[sarumbear]

You still have obvious misunderstandings. The 6 dB loss is in the main signal, not the noise level. Possible incidental spike and/or jitter noise would be much much lower level which should be discussed separately from the universal SINAD discussion.

Duh! Yes teacher, sorry teacher, teach me how SINAD is affected when the S in the acronym is reduced by 6dB, teacher.

It’s late here, and my tolerance for people who are rude for not even bothering to check with whom they are arguing has reached zero.

Good night.

 

[edechamps]

With regard to connecting a balanced output to an unbalanced input: I'd suggest looking at the Rane interconnection note which is an excellent reference on this subject. Apparently there are multiple options, see diagrams 10B and 12.

 

[dualazmak]

A good reminder of the risks! Are the risks compounded in the DM7 case? Being an 8-channel DAC, it's conceivable that the DM7 will feed multiple amps with their own PS. Is a ground loop almost a sure case? Can you be certain that no high voltage / current will flow through one of the unbalanced (PCB?) ground connection, smoking an output stage (best case) or the complete DM7 (worse case)?

I would like to see inside photos in detail what and how are the grounding treatments including the possible TRS ground connection(s) to the chassis in Topping DM7.

Edit:
(Since I have DAC8PRO and I opened the top cover when I received it, I know well what and how are the grounding treatments in DAC8PRO, really excellent for professional use as well as for my home use. Pavel of OKTO is uncomfortable about my sharing the inside photos in detail because the PCB etc. would be their proprietary know-how and/or patent-protected[?] design, though...)

 

[CedarX]

What risks? What high voltage? It is an audio signal!

I was thinking about the weird things happening at each power cycle. I agree, should not see anything serious… besides ground loops!

 

[dualazmak]

Good night.

Good morning from Japan! and good night for you...

 

[NiagaraPete]

All of a sudden multi channel is possible for me.

 

[amirm]

By the way @amirm: I would suggest mentioning somewhere in your review that the outputs are balanced - that seems quite important and it's not mentioned anywhere!

Sure. I will add it now.

 

[confucius_zero]

It’s been discussed at nauseam by now.

link plz