S.M.S.L PO100, PO100 PRO & PO100 AK - Measurements (Digital Interfaces & DAC)

[dejan]

Also, on stutters while playing Tidal on 96kHz - just noticed one. It seems to be happening when playing a mixed playlist where a new song forces PO100 to switch to 96kHz sample rate. Sometimes it feels like it does not settle into the 'groove', instead it stutters (you can kind of make out the song behind the stutters but something is obviously very wrong). Restarting the song fixes it, after which it plays without problems.

Hopefully there will be a driver/firmware update for that at some point. Note however that I used to get that over HDMI as well in the past, so it may be also Tidal-related (at least partially).

 

[DEF]

Also, on stutters while playing Tidal on 96kHz - just noticed one. It seems to be happening when playing a mixed playlist where a new song forces PO100 to switch to 96kHz sample rate. Sometimes it feels like it does not settle into the 'groove', instead it stutters (you can kind of make out the song behind the stutters but something is obviously very wrong). Restarting the song fixes it, after which it plays without problems.

Hopefully there will be a driver/firmware update for that at some point. Note however that I used to get that over HDMI as well in the past, so it may be also Tidal-related (at least partially).

Did you try playing back the file with a different player? Why does it need to be played through Tidal? What if Tidal is the cause?

 

[alfaowner]

Did you try playing back the file with a different player? Why does it need to be played through Tidal? What if Tidal is the cause?

It's not Tidal. I experience no issues when I connect and stream at 96kHz directly via USB to the DAC in my Cambridge Audio Evo 150

you can replace that value with the threshold of your hearing, though and it still is true.

Tidal automatically handles this when the audio quality is set to Max. It selects either 48kHz or 96kHz, depending on availability. Personally, I find 48kHz to be sufficient


I also noticed that the sample rate changes when the soundtrack is streamed at 48kHz or 96kHz. However, if the next soundtrack is at 44.1kHz, the sample rate doesn’t change and remains at the previous value (96kHz). I believe this could be an issue with either Android or Tidal.

 

[dejan]

Tidal automatically handles this when the audio quality is set to Max. It selects either 48kHz or 96kHz, depending on availability. Personally, I find 48kHz to be sufficient

I also noticed that the sample rate changes when the soundtrack is streamed at 48kHz or 96kHz. However, if the next soundtrack is at 44.1kHz, the sample rate doesn’t change and remains at the previous value (96kHz). I believe this could be an issue with either Android or Tidal.

This is not my experience. First off, when quality is set to Max, Tidal will set the sample rate of the source material, which can be 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz (all these sample rates are currently available in the Tidal library - I have several 'liked' songs and albums that use each of them).

Make sure Tidal is configured to use PO100 2024 and have the Exclusive mode toggle turned on. On Windows, these settings tends to not be sticky (particularly if you mess with the cables, connect PO100 on and off all the time). I noticed that I need to re-set these when I boot my HTPC often.

When Tidal is confirmed to use PO100 2024 as the sound device AND exclusive mode is set, it correctly drives the sample rate of the device. I can confirm when playing mixed playlists - as playlist goes through the songs of varying sample rates, the PO100 light changes color accordingly. You can also open "XMOS USB DAC Driver Control Panel" and see the incoming sample rate. For me, it is ALWAYS correct and driven by Tidal on a song by song basis.

Personally, I find 48kHz to be sufficient

I suggest not doing this. It is not a matter of what is sufficient - a song encoded in a particular sample rate will sound best when played back in that sample rate, with no down or up-conversion applied. That's the whole point of the Exclusive Mode - player takes exclusive control of the sound path, bypasses all the OS processing and streams the file using native sample rate with no modification (bit-perfect). I already have Musical Fidelity V-Link USB->SPDIF converter and the only reason I got SMSL PO100 2024 is because V-Link maxes out at 96kHz, and Tidal has a growing number of hi-rez FLAC files encoded in 176.4kHz and 192kHz. When faced with these files, Windows needs to down-convert them to 88.2kHz or 96kHz before sending to the DAC, at which point it is no longer bit-perfect.

In fact, because OS needs to intervene, the whole mixer kicks in, messing up the sound. I can tell because when playing back files higher than 96kHz using V-Link, Windows volume control works and mixer is active because I can play other sources and they get mixed with the Tidal signal. This does not work for 96kHz and under. When using SMSL PO100 2024, exclusive mode is 'direct path to DAC' for all sample rates available in Tidal.

 

[alfaowner]

This is not my experience. First off, when quality is set to Max, Tidal will set the sample rate of the source material, which can be 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz or 192kHz (all these sample rates are currently available in the Tidal library - I have several 'liked' songs and albums that use each of them).

Make sure Tidal is configured to use PO100 2024 and have the Exclusive mode toggle turned on. On Windows, these settings tends to not be sticky (particularly if you mess with the cables, connect PO100 on and off all the time). I noticed that I need to re-set these when I boot my HTPC often.

View attachment 418072

When Tidal is confirmed to use PO100 2024 as the sound device AND exclusive mode is set, it correctly drives the sample rate of the device. I can confirm when playing mixed playlists - as playlist goes through the songs of varying sample rates, the PO100 light changes color accordingly. You can also open "XMOS USB DAC Driver Control Panel" and see the incoming sample rate. For me, it is ALWAYS correct and driven by Tidal on a song by song basis.



I suggest not doing this. It is not a matter of what is sufficient - a song encoded in a particular sample rate will sound best when played back in that sample rate, with no down or up-conversion applied. That's the whole point of the Exclusive Mode - player takes exclusive control of the sound path, bypasses all the OS processing and streams the file using native sample rate with no modification (bit-perfect). I already have Musical Fidelity V-Link USB->SPDIF converter and the only reason I got SMSL PO100 2024 is because V-Link maxes out at 96kHz, and Tidal has a growing number of hi-rez FLAC files encoded in 176.4kHz and 192kHz. When faced with these files, Windows needs to down-convert them to 88.2kHz or 96kHz before sending to the DAC, at which point it is no longer bit-perfect.

In fact, because OS needs to intervene, the whole mixer kicks in, messing up the sound. I can tell because when playing back files higher than 96kHz using V-Link, Windows volume control works and mixer is active because I can play other sources and they get mixed with the Tidal signal. This does not work for 96kHz and under). When using SMSL PO100 2024, exclusive mode is 'direct path to DAC' for all sample rates available in Tidal.

Well there's no such thing you can bypass processing entirely and stream directly. On MacOS in particularly everything goes through the Core Audio framework layer which manages audio input, output and processing. Tidal does not bypass Core Audio in exclusive mode, instead with an access it can control the settings and dynamically adjust the output device sample rate to match the track being played. That said Core Audio is always part of the signal path. Even the sample rates matching it doesn't necessarily mean that Core Audio doesn't perform any additional processing.

 

[dejan]

Well there's no such thing you can bypass processing entirely and stream directly. On MacOS in particularly everything goes through the Core Audio framework layer which manages audio input, output and processing. Tidal does not bypass Core Audio in exclusive mode, instead with an access it can control the settings and dynamically adjust the output device sample rate to match the track being played. That said Core Audio is always part of the signal path. Even the sample rates matching it doesn't necessarily mean that Core Audio doesn't perform any additional processing.

My context is Windows, although I do stream on my MacBook Pro as well. You are correct about MacOS, although historically Core Audio has always been less detrimental to the signal path than Windows. Core Audio is considered bit-perfect if the sample rate of the Audio MIDI Setup matches sample rate of the file being played, and no other source is being mixed in. To that end I presume that Tidal 'Exclusive Mode' simply disables the mixer/volume control and controls Audio MIDI Setup to align sample rate.

As my HTPC is super old and cannot take Windows 11, I will need to finally upgrade to Mac Mini M4, at which point MacOS audio will become my context . To toss another log on the 'bits is bits' fire, I connected my M1 MacBook Pro laptop to SMSL PO100 2024 (using the provided short USB C -> USB C cable) and my Audioquest Cinnamon coaxial cable to AVR. Needless to say, it sounded very different from my Windows machine playing all the same songs from MacOS Tidal desktop app.

 

[Ali Vardar]

Okay, I finally figured out how to update the firmware, and I can now confirm that the update resolves the low volume issue. Here are the instructions:

Prerequisites:

• PC running Windows 10 or later

Step-by-Step Firmware Update Instructions:

1. Connect your SMSL PO100 2024 to the PC using the provided USB-C cable.
2. Open Device Manager on your PC, locate the SMSL PO100 device, and uninstall any previously installed drivers by right-clicking the device and selecting "Uninstall Device."
3. Download the latest Windows driver for SMSL PO100 2024 from the SMSL website:
   https://www.smsl-audio.com/upload/portal/undefined/SMSLUSBAudioDriver.zip
4. Extract the ZIP file and install the driver "XMOS_USBAudio_v5.70.0_2024-11-08_setup"
5. Download the latest firmware (v3.84) and update tools for SMSL PO100 2024 from this link:
   https://www.smsl-audio.com/upload/portal/undefined/PO100FW384.rar
6. Unzip the downloaded file
7. Open the firmware update tool named "XMOSUSBDACDfu" from the "XmosUSB" folder inside the extracted archive.
8. In the update tool, select the firmware binary file named "PO100_MQA_3.84.bin" that is included in the extracted files.
9. Click "Start" in the tool and wait for the update process to complete. Do not disconnect the SMSL PO100 2024 during this step.
10. Once the update is finished, click "Exit" to close the firmware update tool.

Now you can connect the SMSL PO100 to your phone or any device you want to test it with. Make sure the volume is all the way up on your phone or computer to get the full output. Hope this helps!


Before the update (in v3.83), the SMSL PO100 2024 had volume control in the control panel, and it was set to -40dB by default.

View attachment 417847


After the update, the volume controls are now removed from the control panel, and I assume it is now fixed at 0dB.

View attachment 417848

Unfortunately, after the update, there is still an issue when streaming at 96kHz, from time to time, the soundtracks stutter with Pixel 8 Pro & Tidal. There is no stuttering when playing at 44.1kHz or 48kHz.

Thanks bro it's fixed

 

[renoxd]

I'm sorry if the answer is already given by someone. Two questions:

1. Can I connect SMSL PO 100 Pro to DX7 Pro Topping by using i2s cable? SMSL has i2s OUT, Topping include i2s IN.
2. Can I switch in SMSL PRO 100 Pro between Optical / Coax OUT, and have connected 2 different devices? One to Optical, second one to COAX. I don't expect them to be working at the same time.

Thanks!

 

[Norville]

I'd like to know, if someone is knowledgeable to answer if the PO100pro connected via USB to a RPi4 running Ropieee and then feeding I²S signal to a Sabaj D5 would improve anything at all, or is it wasted money?

 

[Roland68]

I'm sorry if the answer is already given by someone. Two questions:

1. Can I connect SMSL PO 100 Pro to DX7 Pro Topping by using i2s cable? SMSL has i2s OUT, Topping include i2s IN.
2. Can I switch in SMSL PRO 100 Pro between Optical / Coax OUT, and have connected 2 different devices? One to Optical, second one to COAX. I don't expect them to be working at the same time.

Thanks!

The PO100 Pro outputs the signal simultaneously on all outputs, I2S/Optica/Coaxial, which means you can operate 3 DACs on it in parallel.

The PO100 Pro should work with I2S on the Topping DX7 Pro, but there have been problems here in the forum with Topping DACs and the PO100 Pro. A contact on the HDMI cable had to be taped over; if I remember correctly, that was pin 16.
But it definitely works perfectly over coaxial.

 

[Roland68]

I'd like to know, if someone is knowledgeable to answer if the PO100pro connected via USB to a RPi4 running Ropieee and then feeding I²S signal to a Sabaj D5 would improve anything at all, or is it wasted money?

I suspect this is a waste of money.
I had the D5 for a while and it is very good over USB, as Amir's test would suggest. I also tested the DDC from Gustard on the D5 back then, but that made no difference.
The USB interface in the PO100 Pro is a little newer and a little more advanced, but that is way out of the audible range, if there is any improvement at all.

 

[raif71]

I'd like to know, if someone is knowledgeable to answer if the PO100pro connected via USB to a RPi4 running Ropieee and then feeding I²S signal to a Sabaj D5 would improve anything at all, or is it wasted money?

It could be wasted money unless you need 2 sources to connect to the D5 (using usb and i2s) then perhaps the 1st device is a phone (usb audio) and another to i2s via PO100pro.

 

[Good Vibes]

Hi, wondering if anyone can help my plight. I bought the PO100 so I could connect my approx 12 year old Macbook Pro (OSX 10.9.5) to my WiiM Ultra via its USB to Optical function. The MacBooks sole function these days is as a music library which I have spent years collecting and organising. The Mac recognises it as the SMSL PO100 and I have selected to use it for audio output in the System Preferences menu but I don’t get any sound. I have successfully connected it to my wife’s 5 year old iMac and the sound is very clear and without any issues. I’m assuming the issue is with the age/IOS but I think it has reached the point where I can no longer upgrade it. I am hoping I might be able to download a driver or resolve the issue somehow???

Any help is greatly appreciated.

Thank you.

 

[Roland68]

Hi, wondering if anyone can help my plight. I bought the PO100 so I could connect my approx 12 year old Macbook Pro (OSX 10.9.5) to my WiiM Ultra via its USB to Optical function. The MacBooks sole function these days is as a music library which I have spent years collecting and organising. The Mac recognises it as the SMSL PO100 and I have selected to use it for audio output in the System Preferences menu but I don’t get any sound. I have successfully connected it to my wife’s 5 year old iMac and the sound is very clear and without any issues. I’m assuming the issue is with the age/IOS but I think it has reached the point where I can no longer upgrade it. I am hoping I might be able to download a driver or resolve the issue somehow???

Any help is greatly appreciated.

Thank you.

My PO100 AK works perfectly on my MacBook Pro, which is at least 12 years old.

May I ask why you don't use the optical output on your MacBook Pro directly?

 

[Good Vibes]

My PO100 AK works perfectly on my MacBook Pro, which is at least 12 years old.

May I ask why you don't use the optical output on your MacBook Pro directly?

Mine doesn’t have one lol I wish it did.

What IOS are you running on it?

 

[Roland68]

Mine doesn’t have one lol I wish it did.

What IOS are you running on it?

Every MacBook Pro, up to and including 2015, has an optical digital output.
This is the 3.5mm jack output, which is also used for analog, it is a combination jack, called a 3.5mm digital/analog headphone jack.
You can use a TOSLink jack to 3.5mm mini TOSLink plug adapter for €2-5 or a Toslink cable that has the 3.5mm mini TOSLink plug on one side.

Regarding the PO100, what do you use to play the music?

 

[Good Vibes]

Every MacBook Pro, up to and including 2015, has an optical digital output.
This is the 3.5mm jack output, which is also used for analog, it is a combination jack, called a 3.5mm digital/analog headphone jack.
You can use a TOSLink jack to 3.5mm mini TOSLink plug adapter for €2-5 or a Toslink cable that has the 3.5mm mini TOSLink plug on one side.

Regarding the PO100, what do you use to play the music?

I just had to dash to it to check the year, mid 2014! I had no knowledge of there being a combination jack when I bought it. Are you saying mine will definitely have this feature?

I bought the PO100 so that I could play music via the MacBook USB into the WiiM Ultra’s optical in.

 

[Roland68]

I just had to dash to it to check the year, mid 2014! I had no knowledge of there being a combination jack when I bought it. Are you saying mine will definitely have this feature?

I bought the PO100 so that I could play music via the MacBook USB into the WiiM Ultra’s optical in.

Yes, both the 13" and 15" MacBook Pro 2014 have an optical digital output.

Are you playing music with iTunes or something else?

 

[Good Vibes]

Yes, both the 13" and 15" MacBook Pro 2014 have an optical digital output.

Are you playing music with iTunes or something else?

Yes, mainly iTunes.

Thank you very much for pointing that out. I had zero idea that it contained that feature. I really wish I knew that! Does the Toslink adapter maintain full audio quality?

 

[Roland68]

Hi, wondering if anyone can help my plight. I bought the PO100 so I could connect my approx 12 year old Macbook Pro (OSX 10.9.5) to my WiiM Ultra via its USB to Optical function. The MacBooks sole function these days is as a music library which I have spent years collecting and organising. The Mac recognises it as the SMSL PO100 and I have selected to use it for audio output in the System Preferences menu but I don’t get any sound. I have successfully connected it to my wife’s 5 year old iMac and the sound is very clear and without any issues. I’m assuming the issue is with the age/IOS but I think it has reached the point where I can no longer upgrade it. I am hoping I might be able to download a driver or resolve the issue somehow???

Any help is greatly appreciated.

Thank you.

According to your statement, you are also using a very old version of macOS, 10.9.5 is from 2014.
Your MacBook is running the latest version of macOS 11 Big Sur, 11.7.10 from September 2023.
You might want to update, but make a backup with TimeMachine first. According to Apple, you can update directly to 11 Big Sur from 10.9.
macOS 11 Big Sur