Topping DX5II Balanced DAC and Headphone Amp Review

[M.C. Logan]

Also no autoref function, no M/S processing, no stereo width adjustment, no DC protection filter, no phase switch per channel, no deemphasis, no independent EQ for different outputs active simultaneously, no loopback, low line output level, generic drivers, poor support.

It's not designed for studio use though is it? Domestic use doesn't need any of that. Primary use case is probably attached to a network transport driving either headphones or a proper pre/integrated. It is only £300 after all.

 

[Berwhale]

Guys, can you please use normal OS, like Linux, and test this DAC on chosen distro?

Well the 'normal' OS would be Windows from a statistical point of view. What is your point?

 

[Roland68]

That would also circumvent the USB receiver chip, which is the source of the clicking unless it goes MacBook Air -> USB -> Toslink -> USB -> DX5 II. Since the Toslink to USB step would need to be powered that would make isolation more difficult. A USB isolator might be more appropriate for testing USB input.

Using my multimeter, I measured between the ground in the MacBook Air's headphone output using the connection to sleeve on a cable and get around 3.5-4 V AC on the power strip, but only around 350-400 mV AC at the wall socket.

USB is only needed once as an output from the computer; after that, it's pointless.
MacBook Air -> USB -> Toslink -> DX5 II
USB to Toslink is possible with devices like the PO100 2024, PO100 Pro, or Douk Audio U2 PRO. This provides complete galvanic isolation.

I would advise against using cheap USB isolators. While such problems can always be solved with the simplest Intona USB isolator, this hasn't worked reliably with inexpensive USB isolators from the audio sector. I've experienced this countless times among my friends, and there are also a few cases known here in the forum.

 

[JIW]

USB is only needed once as an output from the computer; after that, it's pointless.
MacBook Air -> USB -> Toslink -> DX5 II
USB to Toslink is possible with devices like the PO100 2024, PO100 Pro, or Douk Audio U2 PRO. This provides complete galvanic isolation.

I would advise against using cheap USB isolators. While such problems can always be solved with the simplest Intona USB isolator, this hasn't worked reliably with inexpensive USB isolators from the audio sector. I've experienced this countless times among my friends, and there are also a few cases known here in the forum.

Sure, part of it was academic. Since the USB receiver is the source of the issue and if it is as you claim is made apparent by grounding issues, the problem is solved twofold. I wanted to see whether galvanic isolation would work on the USB input, specifically.

With conversion to Toslink, there is some loss in the formats that can be used as S/PDIF is limited to 24/192. Irrelevant for pretty much everyone, though, me included. There might be some additional jitter, but that should also be no issue.

I have read a bit about USB isolators. See, for instance, here: https://forum.rme-audio.de/viewtopic.php?pid=223103#p223103. There are some cheap ones around 10 € on amazon.de that might work, but they are limited to 12 MBit/s which is also limited to 24/192 or 32/176.4 as 32/192 is already 12.288 million Bit/s. The ones limited to 480 MBit/s cost about as much as the PO100 2024 and the track record of those available on amazon.de at the moment is unclear.

I have decided to try the PO100 2024 although already before reading your latest post.

 

[ziggurcat]

@Berwhale @JIW @Roland68

I just properly tested the Qobuz trick, and there's no popping when the DX5 II is set as the "favourite audio output" device in the app. So it's identical to the thing I experienced with the SMSL RAW MDA-1 where running Qobuz in the BG kept the DAC streaming from going to sleep (which appears to be why it pops/ticks).

I am hoping that there is a way to convince Topping to change the DAC streaming to be always on for Mac users since we don't have the ability to do it ourselves as there is no audio control panel for MacOS. Or maybe even develop a MacOS version of their Windows audio control panel.

I will test things out with the beta FW they sent me for a few more days before giving them the feedback they requested. There have been some funky things, but I'm not considering them to be bugs at this time because it's not an "official" FW (yet).

 

[ziggurcat]

Well the 'normal' OS would be Windows from a statistical point of view. What is your point?

Linux is a man's man OS?

 

[ziggurcat]

Can someone that uses a Mac verify this for me:

I have seen it happen more than one time where the DX5 II will disappear from the list of connected devices in the Audio MIDI app when the Mac has been restarted/shutdown. Connection chain is very simple: Mac >> USB >> DX5 II and all that is required is verify that the DX5 II is listed as a connected device in the Audio MIDI app, then either restart or shutdown/reboot the Mac entirely.

Upon the restart/reboot completion, the DX5 II does not show up in the connected devices for me, and I have had to turn the DX5 II off/on from the back switch to get it to show up again. I'm on a beta FW right now, but I have noticed this happen on official FW releases. I just want to confirm whether this is a me thing or not (I'm not claiming this to be a bug with the DAC as it could very well be the computer's fault).

 

[Bauhaus]

Can someone that uses a Mac verify this for me:

I have seen it happen more than one time where the DX5 II will disappear from the list of connected devices in the Audio MIDI app when the Mac has been restarted/shutdown. Connection chain is very simple: Mac >> USB >> DX5 II and all that is required is verify that the DX5 II is listed as a connected device in the Audio MIDI app, then either restart or shutdown/reboot the Mac entirely.

Upon the restart/reboot completion, the DX5 II does not show up in the connected devices for me, and I have had to turn the DX5 II off/on from the back switch to get it to show up again. I'm on a beta FW right now, but I have noticed this happen on official FW releases. I just want to confirm whether this is a me thing or not (I'm not claiming this to be a bug with the DAC as it could very well be the computer's fault).

It works for me. As you can see.
I’ve also attached my Mac configuration. As you can see, I’m on the last beta as well. I could try using the MacBook Pro M2 Pro later, but I currently use the official Tahoe on this one.
Connection chain: Mac Studio > USB > DX5 II

Do I have to turn off the DX5 II before?

 

[JIW]

I have received the PO100 2024 today. I tested it first with USB cable connected. With both optical and coaxial connection, the start/stop clicks do not occur. Thus, grounding is a particular issue with the USB input if at all. I have ordered some USB isolators and will test with them when they arrive.

I have not tested it without the USB cable being connected, because there were no clicks already with it connected.

There are some clicks when changing sample rate. For optical connection, they are the same whether it is the only connection or one of or both the USB and coaxial cable are connected. Over USB input, they do not occur.

 

[ziggurcat]

It works for me. As you can see.
I’ve also attached my Mac configuration. As you can see, I’m on the last beta as well. I could try using the MacBook Pro M2 Pro later, but I currently use the official Tahoe on this one.
Connection chain: Mac Studio > USB > DX5 II

Do I have to turn off the DX5 II before?

Thanks for checking that -- I do need to stress that this thing could either be my computer or the fact that I'm on an unofficially-released FW at the moment (Topping sent me a beta version FW to regress an issue I reported to them, which I think I can say they did fix), so this could easily just be either of those things -- hence why I was verifying whether it's a me thing (I don't want to cause any panic or anything). I only mentioned this particular thing because I have had the DX5 II disappear from the list of devices on official FWs before.

I do typically flip the switch on the back in order to "reset" when testing. I'm on the latest MacOS (Tahoe 26.1), but did notice this on 15.6.1 as well (Mac Mini M1 2020). It might help if you have the box checked to reopen windows, etc.. upon restart. Notable DX5 II settings is Advanced > On/Off Trigger > Signal. So I would "reset" the DX5 II, check that the DX5 II is there in the Audio MIDI app, restart your Mac, and check the Audio MIDI app again once it has fully restarted.

 

[ziggurcat]

I have received the PO100 2024 today. I tested it first with USB cable connected. With both optical and coaxial connection, the start/stop clicks do not occur. Thus, grounding is a particular issue with the USB input if at all. I have ordered some USB isolators and will test with them when they arrive.

I have not tested it without the USB cable being connected, because there were no clicks already with it connected.

There are some clicks when changing sample rate. For optical connection, they are the same whether it is the only connection or one of or both the USB and coaxial cable are connected. Over USB input, they do not occur.

I can confirm this -- I have a SMSL PO100 Pro as well as a Topping D10s (which is essentially a DDC/USB interface/bridge when using the toslink or coax outputs), and running USB from my Mac to those devices, and toslink/coax out from there to the DAC (doesn't have to be specifically the DX5 II as it was the same with the D50 III) does "eliminate" the popping. The Qobuz trick you found also does work to stop the pops from happening (my previous statement that it did not was only because I legit forgot to set the output audio device in Qobuz). I have brought this up with Topping because it could be a thing they tweak via FW for the Mac FW only, I think, since Windows users can just set it the DAC streaming to be always on (or they legit put it in the settings so that people can set it themselves since it seemingly does not happen to everyone).

I can say that in my quest to figure the issue out, I have tried the Topping HS02 (which I believe if a USB isolator?), and it didn't prevent the popping from happening in my experience, so I would be very doubtful that a USB isolator would change anything. I can also hear pops when changing bit/sample rates in the Audio MIDI app, but I have always taken that as "normal" behaviour.

 

[Bauhaus]

Thanks for checking that -- I do need to stress that this thing could either be my computer or the fact that I'm on an unofficially-released FW at the moment (Topping sent me a beta version FW to regress an issue I reported to them, which I think I can say they did fix), so this could easily just be either of those things -- hence why I was verifying whether it's a me thing (I don't want to cause any panic or anything). I only mentioned this particular thing because I have had the DX5 II disappear from the list of devices on official FWs before.

I do typically flip the switch on the back in order to "reset" when testing. I'm on the latest MacOS (Tahoe 26.1), but did notice this on 15.6.1 as well (Mac Mini M1 2020). It might help if you have the box checked to reopen windows, etc.. upon restart. Notable DX5 II settings is Advanced > On/Off Trigger > Signal. So I would "reset" the DX5 II, check that the DX5 II is there in the Audio MIDI app, restart your Mac, and check the Audio MIDI app again once it has fully restarted.

If I may ask. How to report a problem/issue to the team? Gain mode is driving me crazy

 

[ziggurcat]

If I may ask. How to report a problem/issue to the team? Gain mode is driving me crazy

You can send them an e-mail: [email protected]

 

[Bauhaus]

You can send them an e-mail: [email protected]

Thank you!!

 

[JIW]

I can confirm this -- I have a SMSL PO100 Pro as well as a Topping D10s (which is essentially a DDC/USB interface/bridge when using the toslink or coax outputs), and running USB from my Mac to those devices, and toslink/coax out from there to the DAC (doesn't have to be specifically the DX5 II as it was the same with the D50 III) does "eliminate" the popping. The Qobuz trick you found also does work to stop the pops from happening (my previous statement that it did not was only because I legit forgot to set the output audio device in Qobuz). I have brought this up with Topping because it could be a thing they tweak via FW for the Mac FW only, I think, since Windows users can just set it the DAC streaming to be always on (or they legit put it in the settings so that people can set it themselves since it seemingly does not happen to everyone).

I can say that in my quest to figure the issue out, I have tried the Topping HS02 (which I believe if a USB isolator?), and it didn't prevent the popping from happening in my experience, so I would be very doubtful that a USB isolator would change anything. I can also hear pops when changing bit/sample rates in the Audio MIDI app, but I have always taken that as "normal" behaviour.

I could have remembered that you keep USB connected on the DX5 II.

I doubt the USB isolators will work, but I can try it with only the DX5 II being plugged directly into a wall socket. If the isolator does not remove the clicks in that case, the ground connection between the MacBook and the DX5 II cannot be the cause of the issue.

Another issue with the USB input is that in exclusive mode it clicks and cuts the first half second or so of the first track. Keeping the USB receiver on with Qobuz or TASCAM Hi-Res Editor does not change that. With S/PDIF input, it works properly although the SMSL PO100 2024 uses the same USB receiver chip.

EDIT: The last paragraph is about exclusive mode in TIDAL. In foobar2000, there appear to be no such issues. See my post below.

 

[ziggurcat]

I could have remembered that you keep USB connected on the DX5 II.

I doubt the USB isolators will work, but I can try it with only the DX5 II being plugged directly into a wall socket. If the isolator does not remove the clicks in that case, the ground connection between the MacBook and the DX5 II cannot be the cause of the issue.

Another issue with the USB input is that in exclusive mode it clicks and cuts the first half second or so of the first track. Keeping the USB receiver on with Qobuz or TASCAM Hi-Res Editor does not change that. With S/PDIF input, it works properly although the SMSL PO100 2024 uses the same USB receiver chip.

Yeah, I maintain a USB connection only for transferring data (i.e. FW or Topping Tune PEQ profiles), but USB is not checked as an active input in the DAC's settings since it apparently isn't required for that purpose (so I have OPT as the only available input). Though, right now I am trying out the Qobuz thing to see which configuration I prefer, so right now USB is the only active input.

My hope is that Topping can change something in the FW so that I don't have to use any additional devices in the connection chain or have something like Qobuz running in the BG.

 

[JIW]

After some more testing, the PO100 2024 also has issues with exclusive mode in TIDAL. It does sometimes also cut the start but sometimes also has a hick-up within the first second. With exclusive mode in foobar2000, there are no such issues.

EDIT: After restarting the DX5 II and the MacBook Air this no longer occurs.

 

[JIW]

I have found an issue using Qobuz to keep the USB receiver on. It disables the media keys for both TIDAL and Apple Music. TASCAM Hi-Res Editor does not do this.

 

[Barncore]

Hey guys, what PCM filter settings are you favouring?

I've been using F-2 for the past few months. My friend just got the device as well based on my recommendation, so i'm reassessing which filter to recommend. I remember F-2 and another one were highly regarded here. I've searched through 15 pages of this thread but can't find what the other one was.

 

[ziggurcat]

Hey guys, what PCM filter settings are you favouring?

I've been using F-2 for the past few months. My friend just got the device as well based on my recommendation, so i'm reassessing which filter to recommend. I remember F-2 and another one were highly regarded here. I've searched through 15 pages of this thread but can't find what the other one was.

Personally, I cannot hear a single audible difference between any of the filters, but I have it set to F-3.