Topping DM7 8-Channel DAC Review

[Sokel]

Okto uses digital volume control. Ultralite Mk5 uses digital volume control. Topping DM7 uses digital volume control. And so on.

Running a DAC with no attenuation and using a downstream analog volume control potentially has a noise benefit over digital volume control (whether in DSP or DAC) as it will attenuate noise from the DAC at lower volume levels. However in practice such multichannel volume controls often have channel imbalance issues and typically have worse noise performance than the DAC alone, see the Volume8 as an example -> https://www.audiosciencereview.com/forum/index.php?threads/spl-volume8-review.34870/.

A big benefit of these high dynamic range DACs is you can use digital volume control and not have any noise issues.

Michael

So,what it really says on the manual is that it does digital attenuation on the analog outputs(don't they all?).That's a nice clarification.
Thanks!

 

[dualazmak]

Does it matter if the attenuation applies on digital or analog like Okto for example (if I'm not mistaken)?

My understanding; Okto DAC8PRO's gain/volume control is configured by digital attenuation functionality of ES9028PRO reflecting to volume/gain of DAC8PRO's analog out, right?

In ES9028PRO's Datasheet, we can see;

 

[Sokel]

My understandings on Okto DAC8PRO's gain/volume control is configured by digital attenuation functionality of ES9028PRO reflecting to volume/gain of DAC8PRO's analog out, right?

In ES9028PRO's Datasheet, we can see;
View attachment 220935

Yes,my confusion came from the Okto's manual:

But it's clear now.
Thanks!

 

[mdsimon2]

Yes,my confusion came from the Okto's manual:


View attachment 220939

But it's clear now.
Thanks!

Just having a volume control (of any kind) that acts on all analog outputs is a relatively rare feature in the multichannel DAC world as many multichannel DACs are pro audio interfaces where the volume knob only controls the volume of the main output channels.

Which is why when a DAC has this feature (Okto, DM7, Ultralite Mk5, 18i20) it is so appreciated. I've been eyeing an Audient Evo 16 for example as it has a nice big knob and display but it will only control 2 of the 8 analog outputs.

Michael

 

[Krillin]

Sigh... Topping just release an AV Processor with Dirac Live already and make Amirm happy, there has yet to be an AV processor break into the blue SINAD zone.

I applaud Topping for releasing this 8-channel DAC and it was much needed. But the main purpose of this DAC is to use a computer because AV processor's are so darn expensive and have horrible measurements (typically). With what Topping has been able to achieve it would be something to look forward to.

 

[Music1969]

can make up the gain afterwards in the chain. But only up to the limits of amplification power.

I guess a key point here about this filter insertion loss.

This making up of lost gain, I can do with my convolver by boosting gain levels equally across all channels before it gets my DAC

I think @jtwrace is worrying and confused too much about the DAC side , a "problem" so easily solved in a good convolver itself . Mine being HQPlayer (can feed it from Roon, UPnP, any digital source, any analogue source)

Maybe he needs to "think about it..." some more

 

[sarumbear]

Honestly looking at this, it is hard to understand who it is for. Since it only has USB input; it can only be used with things like computers (or maybe phones)? So what is supposed to drive this thing? I mean 8 channels is quite a bit but they seem to all be 6.35mm outputs instead of something like XLR or even RCA?

Why make things so complicated?

As you don’t understand who is this device for it’s obvious that it’s not for you.

 

[Jimster480]

As you don’t understand who is this device for it’s obvious that it’s not for you.

Yea it seems that way. I originally was excited when I saw it because I was thinking I could use it for a Home Theater. But it isn't for that it seems.

 

[sarumbear]

Yea it seems that way. I originally was excited when I saw it because I was thinking I could use it for a Home Theater. But it isn't for that it seems.

You can use it for a surround only (no Atmos) HT but you need to handle the digital processing in a computer. This is just a DAC which is just one element of a HT setup.

 

[DWPress]

I guess a key point here about this filter insertion loss.

Yes. I'm making up for the lost gain digitally as well doing it after convolution but before it gets to the XO part of the digital chain. Like I said, I'm not using the paid apps to make life easier, I do it all in the cross platform app called Element which acts as a host for AU and VST plugins so I can feed any digital or analog source to it as well for correction.

 

[Jimster480]

You can use it for a surround only (no Atmos) HT but you need to handle the digital processing in a computer. This is just a DAC which is just one element of a HT setup.

yea I have an HTPC. My TV also can process Atmos but not likely how this wants to be outputted to especially since it only has USB.

 

[Music1969]

Yes. I'm making up for the lost gain digitally as well doing it after convolution but before it gets to the XO part of the digital chain. Like I said, I'm not using the paid apps to make life easier, I do it all in the cross platform app called Element which acts as a host for AU and VST plugins so I can feed any digital or analog source to it as well for correction.

Yes I've used Element for years. Great app.

Main point was not to you but jtwrace complaining about not being able to adjust levels in Topping to counter this insertional loss.

There's many ways to offset this insertional loss via DSP, way before it reaches DAC, let alone amps.

Not being able to do this on the Topping is not a problem in practical terms.

Ideal place to do it is the convolver itself, if one has the software capable

 

[DWPress]

As they say - a picture is worth a 1000 words.

Here is a screen capture of my current set up in Element. Each little box is a audio plugin doing anything from simple volume control to hosting convolution filters as well as the crossover. A little compression for occasional loud playing on the sub channel, time delays and that's it. Each box can be made active or not and the channel strip below monitors what's happening in real time. Clicking on a box will give you the GUI for whatever plugin you are using like Dirac, Hang Loose Convolver or any other AU or VST plugin you would use in any professional sound production application. Drag and drop plugins from the side bar, connect them together with "patch cables", define your input and output devices (real or virtual) and you're good to go!

 

[Music1969]

As they say - a picture is worth a 1000 words.

Here is a screen capture of my current set up in Element. Each little box is a audio plugin doing anything from simple volume control to hosting convolution filters as well as the crossover. A little compression for occasional loud playing on the sub channel, time delays and that's it. Each box can be made active or not and the channel strip below monitors what's happening in real time. Clicking on a box will give you the GUI for whatever plugin you are using like Dirac, Hang Loose Convolver or any other AU or VST plugin you would use in any professional sound production application. Drag and drop plugins from the side bar, connect them together with "patch cables", define your input and output devices (real or virtual) and you're good to go!

Very impressive !

 

[dualazmak]

As they say - a picture is worth a 1000 words.

Very nice, I fully agree with you.

For people who would be interested in DM7 (and Okto DAC8PRO, MOTU UltraLite Mk5, FOCUSRITE Scarlett 18i20, etc.), pictures and diagrams showing the full utilization of these multichannel DACs are really worth a 1000 words!

As we had nice and comfortable discussion in your multichannel thread, our goals (yous and mine) would be almost similar with a little bit different approach, while we both are fully utilizing multichannel DAC. I would like to share here, therefore, a few of my pictures and diagrams which, together with your pictures/diagrams, provide clear-cut understandings for many people visiting this thread on DM7. The details of my latest system setup as of May 30 2022 can be found here.

One of the unique features of my setup would be utilization of "integrated amplifiers" after the multichannel DAC (in the way of "the right person in the right place") which enables safe and flexible "on-the-fly" relative gain tuning between all of the SP drivers depending on the "hearing capabilities/decline" and/or "hearing preferences/tastes" of the audiences/listeners, while keeping all the parameters in PC (Windows 11 Pro) remain unchanged, as shared here.

 

[MAB]

For people who would be interested in DM7 (and Okto DAC8PRO, MOTU UltraLite Mk5, FOCUSRITE Scarlett 18i20, etc.), pictures and diagrams showing the full utilization of these multichannel DACs are really worth a 1000 words!

I completely agree, these diagrams are extremely helpful.
The DM7 really needs better documentation and this thread proves it to me. Almost every use I can think of is for enthusiast and critical aspects of operation are just not identified in the DM7 manual or website. This isn't a $79 dongle anymore...
Also, I actually worry people will be buying the unit thinking they can use in a 7.1 surround sound implementation. I see Topping did update the documentation to try to steer people away from this thought, but it just doesn't feel enough.

When I think of documentation, I think of the classics, like this:

 

[JohnYang1997]

Several people have raised questions regarding unbalanced connection using DM7.

In short, don't do it.

There are many nuances to this same as D10 Balanced. The fear came from us in the D10 Balanced days were that people would directly connect TS to RCA cable to the output shorting out the output stage. Even though it wouldn't damage it, it's still very not good to just short out an output of a device.

Regarding TRS to RCA cable that left + or - open, there can be small amount of residual DC offset at the output, last time I check it is smaller than D10 Balanced's. It's certainly not prohibited to do it although not recommended. The next stage should have DC blocking to make sure the DC offset from the DAC doesn't get amplified 20-30 times. And unfortunately unbalanced multiple devices connection will extremely likely cause ground loop. Even it is possible to do so without harm to any components. It likely would cause some degree of hum/buzz/high pitch noise from USB etc. It can be done but quality is not assured.

So in the end, balanced all the way will almost guarantee good quality audio in a system.

 

[MCH]

Several people have raised questions regarding unbalanced connection using DM7.

In short, don't do it.

There are many nuances to this same as D10 Balanced. The fear came from us in the D10 Balanced days were that people would directly connect TS to RCA cable to the output shorting out the output stage. Even though it wouldn't damage it, it's still very not good to just short out an output of a device.

Regarding TRS to RCA cable that left + or - open, there can be small amount of residual DC offset at the output, last time I check it is smaller than D10 Balanced's. It's certainly not prohibited to do it although not recommended. The next stage should have DC blocking to make sure the DC offset from the DAC doesn't get amplified 20-30 times. And unfortunately unbalanced multiple devices connection will extremely likely cause ground loop. Even it is possible to do so without harm to any components. It likely would cause some degree of hum/buzz/high pitch noise from USB etc. It can be done but quality is not assured.

So in the end, balanced all the way will almost guarantee good quality audio in a system.

Thank you John, this is very relevant info. For me it means i will have to either sell my subs or wait for the unbalanced dm7

 

[Trell]

I completely agree, these diagrams are extremely helpful.
The DM7 really needs better documentation and this thread proves it to me. Almost every use I can think of is for enthusiast and critical aspects of operation are just not identified in the DM7 manual or website. This isn't a $79 dongle anymore...
Also, I actually worry people will be buying the unit thinking they can use in a 7.1 surround sound implementation. I see Topping did update the documentation to try to steer people away from this thought, but it just doesn't feel enough.

When I think of documentation, I think of the classics, like this:
View attachment 221042

Better manuals is something Topping should work on.

 

[da Choge]

In short, don't do it.

From the tenor of the last several posts, this "inquiry" may not receive a lot of love, but my interest in the Topping DM7 is to use it as a DAC for multi-channel music fed by the USB output of a streamer which transmits 5.1 or 7.1 multichannel music files from a Roon ROCK NUC; NOT as a part of a Home Theater AVR. The main FR and FL channels would be amplified by a balanced stereo amp fed from the first two channels of the DM7. I would like to feed the the remaining channels back into the single-ended RCA 7.1 multichannel inputs of my AVR and use its amplification for these surround channels.

Because of what John Yang has posted, I think I would not want to use modified TRS to RCA cables (ones which would float the negative line). However, I would consider using balanced-to-unbalanced transformers (two higher quality units are denoted below from RDL). I know this would degrade the signal of the surround channel signals somewhat, but as they are just the surround channels, they are less of a concern than the main two front stereo channels. And for stereo music listening, I still get all the goodness of the balanced high-quality DM7 DAC.

These are the units I would consider:

RDL TX-AFC1F

RDL FP-BUC2

The FP-BUC2 has better specs than the TX-AFC1F, but it is also a line amplifier, which could come in handy in balancing the signal strengths of the surround channels with respect to the main balanced stereo line. I would obviously need 2 to 3 of the second unit to accomplish what I want.

I'm asking the more knowledgeable (than me) members of the forum as to what they think of this scheme, audio-wise? -- sound or unsound