Help with solving a problem with Topping D10s

[ziggurcat]

Some people here are already familiar with some recent troubleshooting I have gone through regarding a popping issue that ended up being cause by my Mac Mini (and, it turns out, a Macbook Air M2 as well), and the solution to the problem was to introduce a USB DDC (SMSL PO100 Pro) into the chain, and that fixed the problem (thanks to the amazing help from @Roland68). I looked a little bit more into USB DDCs, and it turned out I had a couple of Topping D10s DACs sitting around that can also be used in that capacity by using the toslink or coax outputs.

I decided to then try out the D10s for a few reasons:

1. It's a much larger, sturdier box compared to the PO100 Pro, and it has a big display that shows the sample rate.
2. Because the PO100 Pro is pretty small, the cables do like to pull it in a bunch of different directions, which isn't an issue with the D10s.

I connected the D10s, and in my Mac's MIDI app, set the bit/sample rate to 24-bit/192kHz (which I believe is the max it can do with optical/coax out even though 32-bit is available in the dropdown menu), and it all seemed to function just fine.

Today, however, something changed. Now -- for whatever reason -- the sound will cut out/stutter, and I have no idea why because it had been working flawlessly for a few days. The only thing I had technically changed was the toslink cable (went from a 3ft to a 1.5ft cable). Playing music it will stutter a bunch at the beginning of a song, and sort of stop (though I think it does intermittently cut out through out the song). Watching a Youtube video is impossible -- there's virtually no audio.

With the shorter cable, if I drop the sample rate down to 24-bit/96kHz (or lower) on the D10s, everything works perfectly fine again -- I can even change the sample rate on the fly, and it will go from being fine at 96kHz to stuttering at 192kHz. Sometimes it will be fine at 24/192 with the shorter cable, but I have noticed there's some wiggle with the connector on both ends, and if I jiggle it a little bit, the sound will start to go awry (i.e. lots of stuttering/cut-outs). I can also plug the shorter cable in, not touch anything, and it will stutter/cut out, so it isn't always caused by jiggling the connectors. . I can also wiggle the connectors when the sample rate is set to 96kHz, and nothing happens.

If I plug the shorter cable into the PO100 Pro, and set the sample rate to 24-bit/192kHz, everything works perfectly fine. If I wiggle the connector on the DAC end (the PO100 Pro end has no wiggle), nothing happens.

If I revert back to my original 3ft toslink cable, and set the sample rate on the D10s back to 24-bit/192kHz, everything is fine. I can jiggle the connectors, and nothing happens (so far). They do feel more secure, but there's still a little bit of wiggle.

I have tried coax out from the D10s to the D50 III and there are no issues with that connection, regardless of the bit/sample rate.

Is this all because of a loose toslink connection with the shorter cable or is there something else to it?

 

[solderdude]

For TOSLINK the max. is usually 24/192 but that is the max. most receivers in DACs can do.
Sometimes it is on 'the edge' of what can be received so some DACs are limited to 24/96.
This has to do with the fiber optic connection as well.
All of them have attenuation (could even be dirt on the surface,
Sometimes the longer ones have 'better' optical conductors, sometimes the shorter ones are poorly polished or have other issues (internal break).

So.. it is highly likely some DAC's do 24/192 flawlessly or with errors.
Best to simply use 24/96 as most music is 16/44.1 or 16/48 anyway and upsampling (the DAC internally upsamples too) will not bring better fidelity.

Moral of the story... set your source to 24/96 if you want a fixed bitrate.

 

[ziggurcat]

For TOSLINK the max. is usually 24/192 but that is the max. most receivers in DACs can do.
Sometimes it is on 'the edge' of what can be received so some DACs are limited to 24/96.
This has to do with the fiber optic connection as well.
All of them have attenuation (could even be dirt on the surface,
Sometimes the longer ones have 'better' optical conductors, sometimes the shorter ones are poorly polished or have other issues (internal break).

So.. it is highly likely some DAC's do 24/192 flawlessly or with errors.
Best to simply use 24/96 as most music is 16/44.1 or 16/48 anyway and upsampling (the DAC internally upsamples too) will not bring better fidelity.

Moral of the story... set your source to 24/96 if you want a fixed bitrate.

Thanks for taking the time to respond, I really appreciate it!

What would it be about the PO100 Pro that doesn't cause the audio to stutter/cut out? Is it the XMOS version (XU208 in the D10s vs. XU316 in the PO100 Pro)? I did also use the D10s in my desktop system when I first set it up (and I was unknowingly using it in its "bridge" mode because I was far less knowledgeable... not that I know anything now ) -- It was the same Mac Mini I have now, connected USB to the D10s, then optical out to a Cambridge AXR100 integrated amplifier. Not a single issue, and it was configured to 24-bit/192kHz the whole time. It was also the same 3ft optical cable I mentioned in the OP.

And if I use the coax output on the D10s, there's no problem at all, even at the max 24-bit/192 kHz. I even tried a third optical cable (also 3ft in length), and it seemed to be a little better, but did start to stutter the moment I wiggled the connector. It was a cable that is similarly-designed to the OG 3ft cable. For reference, the three optical cables are:

https://www.monoprice.com/product?p_id=2764 - this is the cable that has no problems

https://www.amazon.ca/dp/B0CPYQKMHT?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 - this is the short cable

https://www.primecables.ca/p-312784...ector-7-lengths-available-monoprice#sku310766 - this is the similarly-designed one. The link says it's Monoprice, but it is not (there's no Monoprice logo/text on the ferrule, no tethered end caps, and the OD of the cable is slightly thinner).

And because I have two of them, I even tried the other D10s, and it was the same results.

I figure either I use the PO100 Pro with the shorter optical cable (since it seems to be working without issue so far), or use the D10s with the OG optical (even though having all of the unnecessary extra cable length really irritates me), use the shorter cable with the D10s at a reduced bit/sample rate or use a coax connection -- which then begs the question of what, if any, noise/distortion would be introduced with that option (or is it identical to toslink? none of the reviews show any results using the coax inputs/outputs).

I also want to really stress that nothing in my response here is pushing back at you -- I've read, and have taken in everything you've said, all of my questions are meant to gain a better understanding of the issue, and any additional information is meant to clarify the scenario/connection chain, etc...

 

[Steven Holt]

Why are you using the D10s, or the SMSL, at all? The Mac Mini has an excellent internal DAC. The more things you put in the signal chain, the better chance for mischief.

 

[ziggurcat]

Why are you using the D10s, or the SMSL, at all? The Mac Mini has an excellent internal DAC. The more things you put in the signal chain, the better chance for mischief.

I'll try to be as succinct as I can below:

I noticed a popping issue whenever I would pause/stop any audio content (system sounds, Youtube of playing music through the Music app). It apparently went completely unnoticed for a long time, and the 3e Audio A7 amplifier I got almost two months ago really brought it out. At first I thought it was the new amp since I hadn't noticed anything with any other amplifier I had used up until that point. After extensive/exhaustive testing, I was able to finally hear the popping through headphones under pretty specific conditions -- D50 III in preamp mode, L50 HPA gain set to Medium or High. Volume level didn't matter, it was audible even at -70dB set on the D50 III with the L50 at Medium or High gain. No audible popping with the L50 set to Low gain (even with the volume level as high as -10dB on the D50 III).

Because it was audible with headphones, it completely absolved the A7 amplifier, so then my focus was on getting around using a USB connection since that was the obvious cause of the problem. A USB isolator was tried, but it didn't resolve anything. Since it was clear that the popping wasn't present with a Bluetooth or optical connection, it was suggested that I try something like the SMSL PO100 Pro since it converts a USB connection to a different digital signal format.

The popping would only occur when a USB connection was being used from my Mac Mini to D50 III. It would also happen (to a lesser degree) if I used the 3.5mm headphone output from the Mac to the A7 amp directly (via 3.5mm to RCA cable). When using the Bluetooth input, and streaming from the Mac Mini to D50 III then TRS out to the A7, no popping. Also no popping with an optical connection from my bedroom TV to the D50 III then TRS out to the A7.

I had the same popping results with a Macbook Air M2, so it is definitely something with the USB connection, and I don't think it is the DAC because I connected a Topping E50 DAC to my Macbook Air during that test.

Adding the USB DDC "fixed" the popping completely (or at the very least, it suppresses it enough to make it inaudible). I only thought of using the D10s because it has the ability to function like the PO100 Pro (when using the optical/coax outputs on the D10s, it bypasses its internal DAC, so it only acts as a bridge), and I like its larger footprint/display a little more. There is no audible difference between the two devices.

Trust me, I'm no fan of adding additional, seemingly unnecessary components, but if this allows me to use my new amp in the system I intended it to be, I am not going to scoff at something that works. If there was nothing with the Macbook Air, then I could at least narrow it down to the Mac Mini, but because it also happened with that computer, it has to be something with how Apple handles their USB output signals. Roland68, who helped me out immensely, suspected it was a ground issue from the very beginning (which I admittedly was skeptical of because I usually only associate a ground issue with a hum/buzz, and none of that was happening).

Anyway, I hope that clarifies/explains why I have to have it set up the way I do . The whole thing is a nightmare

edit: for reference, this was the popping issue: https://drive.google.com/file/d/1UXNyGBo5Co1GBhUdgh16LXGLN0iMpG34/view - the popping can be heard at 16 seconds.

 

[solderdude]

Thanks for taking the time to respond, I really appreciate it!

What would it be about the PO100 Pro that doesn't cause the audio to stutter/cut out? Is it the XMOS version (XU208 in the D10s vs. XU316 in the PO100 Pro)? I did also use the D10s in my desktop system when I first set it up (and I was unknowingly using it in its "bridge" mode because I was far less knowledgeable... not that I know anything now ) -- It was the same Mac Mini I have now, connected USB to the D10s, then optical out to a Cambridge AXR100 integrated amplifier. Not a single issue, and it was configured to 24-bit/192kHz the whole time. It was also the same 3ft optical cable I mentioned in the OP.

And if I use the coax output on the D10s, there's no problem at all, even at the max 24-bit/192 kHz. I even tried a third optical cable (also 3ft in length), and it seemed to be a little better, but did start to stutter the moment I wiggled the connector. It was a cable that is similarly-designed to the OG 3ft cable. For reference, the three optical cables are:

https://www.monoprice.com/product?p_id=2764 - this is the cable that has no problems

https://www.amazon.ca/dp/B0CPYQKMHT?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 - this is the short cable

https://www.primecables.ca/p-312784...ector-7-lengths-available-monoprice#sku310766 - this is the similarly-designed one. The link says it's Monoprice, but it is not (there's no Monoprice logo/text on the ferrule, no tethered end caps, and the OD of the cable is slightly thinner).

And because I have two of them, I even tried the other D10s, and it was the same results.

I figure either I use the PO100 Pro with the shorter optical cable (since it seems to be working without issue so far), or use the D10s with the OG optical (even though having all of the unnecessary extra cable length really irritates me), use the shorter cable with the D10s at a reduced bit/sample rate or use a coax connection -- which then begs the question of what, if any, noise/distortion would be introduced with that option (or is it identical to toslink? none of the reviews show any results using the coax inputs/outputs).

I also want to really stress that nothing in my response here is pushing back at you -- I've read, and have taken in everything you've said, all of my questions are meant to gain a better understanding of the issue, and any additional information is meant to clarify the scenario/connection chain, etc...

The issue is the limited bandwidth of the TOSLINK receiver in the device combined with the attenuation and optical coupling of the used connectors.
24/192 is right on the edge of what works. Some TOSLINK receivers (production tolerance/spread) are just a bit better or worse. Some optical connectors are just a bit better or worse. It's the combination that determines if 192 is working O.K. or has some bit errors (resulting in stutter etc.)

 

[ziggurcat]

The issue is the limited bandwidth of the TOSLINK receiver in the device combined with the attenuation and optical coupling of the used connectors.
24/192 is right on the edge of what works. Some TOSLINK receivers (production tolerance/spread) are just a bit better or worse. Some optical connectors are just a bit better or worse. It's the combination that determines if 192 is working O.K. or has some bit errors (resulting in stutter etc.)

I'll leave the D10s in because I really do like the box/display, and keep it at 24/96, then, since that seems to work just fine, and there's zero audible difference.

 

[Roland68]

Thanks for taking the time to respond, I really appreciate it!

What would it be about the PO100 Pro that doesn't cause the audio to stutter/cut out? Is it the XMOS version (XU208 in the D10s vs. XU316 in the PO100 Pro)? I did also use the D10s in my desktop system when I first set it up (and I was unknowingly using it in its "bridge" mode because I was far less knowledgeable... not that I know anything now ) -- It was the same Mac Mini I have now, connected USB to the D10s, then optical out to a Cambridge AXR100 integrated amplifier. Not a single issue, and it was configured to 24-bit/192kHz the whole time. It was also the same 3ft optical cable I mentioned in the OP.

And if I use the coax output on the D10s, there's no problem at all, even at the max 24-bit/192 kHz. I even tried a third optical cable (also 3ft in length), and it seemed to be a little better, but did start to stutter the moment I wiggled the connector. It was a cable that is similarly-designed to the OG 3ft cable. For reference, the three optical cables are:

https://www.monoprice.com/product?p_id=2764 - this is the cable that has no problems

https://www.amazon.ca/dp/B0CPYQKMHT?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 - this is the short cable

https://www.primecables.ca/p-312784...ector-7-lengths-available-monoprice#sku310766 - this is the similarly-designed one. The link says it's Monoprice, but it is not (there's no Monoprice logo/text on the ferrule, no tethered end caps, and the OD of the cable is slightly thinner).

And because I have two of them, I even tried the other D10s, and it was the same results.

I figure either I use the PO100 Pro with the shorter optical cable (since it seems to be working without issue so far), or use the D10s with the OG optical (even though having all of the unnecessary extra cable length really irritates me), use the shorter cable with the D10s at a reduced bit/sample rate or use a coax connection -- which then begs the question of what, if any, noise/distortion would be introduced with that option (or is it identical to toslink? none of the reviews show any results using the coax inputs/outputs).

I also want to really stress that nothing in my response here is pushing back at you -- I've read, and have taken in everything you've said, all of my questions are meant to gain a better understanding of the issue, and any additional information is meant to clarify the scenario/connection chain, etc...

The problem is likely due to the poor quality/fit/workmanship/material of the Toslink cables/connectors available today.
Good POF fiber optic cables have 100 times higher attenuation than high-quality quartz fiber optic cables. With cheap POF Toslink cables, the ratio is even worse, and therefore even small changes, as mentioned above, have a much greater impact.

See if you can find a cable shop that carries high-quality POF sold by the meter (approx. €1-5 per meter). They can also assemble ready-made cables from it, for approximately €7-14 per meter. High-quality quartz fiber optic cables cost approximately €20-25 per meter, including connectors and assembly.

 

[ziggurcat]

The problem is likely due to the poor quality/fit/workmanship/material of the Toslink cables/connectors available today.
Good POF fiber optic cables have 100 times higher attenuation than high-quality quartz fiber optic cables. With cheap POF Toslink cables, the ratio is even worse, and therefore even small changes, as mentioned above, have a much greater impact.

See if you can find a cable shop that carries high-quality POF sold by the meter (approx. €1-5 per meter). They can also assemble ready-made cables from it, for approximately €7-14 per meter. High-quality quartz fiber optic cables cost approximately €20-25 per meter, including connectors and assembly.

Unfortunately, I don't think I have that option where I live (i.e. a place to get POF sold by the foot, and have them assemble a cable), so for now I am sticking with dropping the sample rate on the D10s down to 96kHz as it is working flawlessly under that setting (and I've really tried to get it to stutter). It's just very strange that the one cable that gives me the most trouble works perfectly fine with the PO100 Pro (no stuttering or anything, even after some slightly more rigourous jiggling on either end of the cable).

I think if I'm really bothered by it, I can use the coax output since it doesn't suffer from any stutter/cut out at 24/192, but the only reliable RCA connectors I have used are from Blue Jeans (unless there's another brand that uses the same Canare RCAPs as them for less money), and I'm very hesitant to be ordering anything from the US right now. Being in Canada, I'm trying to avoid buying any US products until dingus south of us is gone. I'd just need a 1ft cable (0.3m?).

Also, my DX5 II shipped this morning!

 

[ziggurcat]

@Roland68 -- an update, if you care:

Got my DX5 II set up this evening, and I decided to test out increasing the bit/sample rate for the D10s back up to 24/192 with the same, short optical cable that exhibited the "issue" with the D50 III. Gave it a wiggle on the D10s end since that easily triggered the stuttering, and it doesn't seem to trigger with the DX5 II. Not sure why other than maybe it's something with the D50 III's optical input, but I'll take it. I haven't tried wiggling the optical connector on the DX5 II end, but it's best to leave sleeping dogs lie in that case, I think.

I just wish for something to be consistent

As a side note: I tested just USB from Mac to DX5 II, and the popping issue was greatly reduced compared to how it was set up with the D50 III (and it only seemed to pop once, in both channels), and I had to hold my ear right up to the speaker driver. I'll give it a more thorough test tomorrow when it's daylight, and decide whether I can live with it if it happens to be inaudible from my seating distance.

 

[ziggurcat]

New thing, but super minor:

I have noticed that when I put my A7 amp into standby mode, there's a much more noticeable pop when the amp shuts down. This was not there prior to introducing the USB DDC into the system, and I am using an optical connection to the DX5 II via the Topping D10s. If I configure it so that my DX5 II is connected to my Mac via USB (I still maintain a USB connection for when I need to update FW, and use Topping Tune), the A7 makes the tiniest of ticks that is almost drowned out by the relay switch clicking upon shutdown. Also -- with the D10s configuration, if I switch the DX5 II's output to HPA BAL, and then shut down the A7, there's only a very tiny pop (a little bit louder than the USB connection, but not nearly as loud as when the DX5 II is set to LO BAL).

Now, this is all very minor, so I'm not too concerned, it's just that there's a noticeable difference with the two connections -- but at the same time I'm wondering if there's anything that can be done to have it behave the way it does with the USB connection.

 

[ziggurcat]

Hey @Roland68 I discovered something today, and wondering if I can pick your brain on it -- you're obviously under no obligation to even respond, but it's related to the popping.

To preface things a bit, I have been troubleshooting a hissing issue I may have with my DX5 II that I believe is related to how I have to have things set up (if you remember, I had to put a USB DDC in between my Mac and DAC to resolve the popping issue caused by the Mac). One of the tests is to only connect the DX5 II via USB, and only have USB as the active input in the settings. When I have encountered the hiss, it has only been when my DX5 II has been set to only have the OPT input active in the Input Option menu, but a USB cable is connected (I discovered that the USB input does not need to be selectable in order to use Topping Tune or Update FW). Topping had asked me to test this when they responded to my report.

Because I have been trying a USB-only connection, I noticed something I hadn't before. When playing anything from the Music app, popping occurs once the audio has stopped. Same result if playing a system sound from the System Settings > Sound menu. The discovery is that if I play any audio from a web-based source (Bandcamp or YouTube, for example), no pop from either the headphones or speakers. This may not be something you know much or anything about, but what would the technical differences be between playing a web-base audio source vs, from an OS app? And does that information offer a hint to what's actually causing the popping?