Hello Everyone,
This is a review and detailed measurements of the SMSL PL20 CD Player and Transport.
It was kindly sent to me by Aoshidaudio.com.
SMSL PL20 - Presentation
This one was released just before Christmas 2025, and is hosting 2 CS43131 DACs. The look is similar to the PL100 with a wider front display, so it's easier to know what track is being played from a distance. Its price is roughly 200$.
This new CD Player offers the below features:
It can be powered from a a USB 5V/2A source (battery or phone charger). We also get 2 digital outputs coax and Toslink.
Important note: I received one of the first units produced, before it was publicly available, and I spotted an issue with volume control. I contacted Aoshidaudio right away and they provided me with a prototype firmware, in less than a week, which solved the issue. I guess this has been fixed on units that have been shipped later on, but in case you feel there's an issue with the output volume, feel free to contact me so I can provide you with more insights.
By the way, the volume control has 16 steps (from 0 to 15), and is active in digital and analog domains.
I measured each of the attenuation step (from digital outputs):
User experience
As I'm now used to report, here are some elements about my user experience with this device:
SMSL PL20 - Measurements (RCA Analog out)
All measurements performed with an E1DA Cosmos ADCiso (grade 0), and the Cosmos Scaler (100kohms from unbalanced input) for analog outputs, and a Motu UltraLite Mk5 for digital outputs.
I am consistent with my specific measurements for CD Players, as I described them in the post “More than we hear”, and as I reported them for the SMSL PL200 review.
The SMSL PL20 outputs 2Vrms and the two channels match at 0.05dB (this is good). Phase is dead flat.
----
As usual, let's start with my standard 999.91Hz sine @0dBFS (without dither) from the Test CD (RCA out):
This is a very good result for a CD player even if the right channel suffers more H2 distorsion (the green spike that you see) which brings the SINAD down from 98.4dB to 95.8dB. SNR is already best in class for the Audio CD, even with that max digital level output
Let's try the same at -6dBFS:
Again very good result (worst channel shown in the dashboard, this time). We find again that little more H2 in the right channel, but at -105dBr, we can ignore it.
----
I usually have a look at any potential PS related leakage, and you saw it before, there are none, even if I zoom with a punishing 512k FFT length:
The few spikes you see come from the digital file, quantization errors (or rounding errors with 16bits). This is what I'd like to see with all CD Player.
----
Next is the bandwidth:
This is flat within -0.1dB. Note the small channel imbalance of 0.05dB. No need to ask for more, honestly.
----
Let's have a look at the job of the oversampling filter, with a wider bandwidth:
This oversampling filter is fully active at 26kHz, which is a bit late (I'd prefer 24khz), and so we can see aliases of the two test tones of the AES test that weirdly replicate at around 24kHz. The small rebound of the white noise trace at 24kHz is a second surprise.
These elements indicate heavy processing of the digital signal, my guess. Other tests should confirm.
----
Let's have a look at the multitone test that a lot of you like very much:
We get few unwanted spikes, but nothing of real concern. Can do better though.
----
Oh yes, the jitter test:
We get few spikes, not of concern, but surprisingly, they are not at equal distance from the fundamental. At this point, we shall suspect a resampling before conversion. The same test in digital domain (from the optical output) would confirm.
And indeed, not only my interface locks at 48kHz instead of the expected 44.1kHz, I get the same trace from the Toslink output:
So, we see side bands at 8.1k and 14.9k indicating a correlation between the initial 44.1kHz sampling rate and the resampled 48kHz output.
Indeed, the fundamental of the Jtest is at 44.1kHz / 4 = 11.025kHz
And 48kHz - 44.1kHz = 3.9kHz
And 3.9kHz / 4 = 0.975kHz
And 0.975kHz / 2 = 0.48kHz
And 11'025kHz + 0.48kHz = 11.5kHz
Conclusion: the side bands are centered around 11.5kHz as shown by the plot.
This of course means there is a Sample Rate Converter always in action. I suppose this is to tackle all different possible sampling rate inputs that this CD player can handle. The next test will tell us if this SRC appreciates inter-sample overs (generally not...).
----
Started with the Teac VRDS-20 review, and on your request + support to get it done (more here), I'm adding now an "intersample-overs" test which intends to identify the behavior of the digital filtering and DAC when it come to process near clipping signals. Because of the oversampling, there might be interpolated data that go above 0dBFS and would saturate (clip) the DAC and therefore the output. And this effect shows through distorsion (THD+N measurement up to 96kHz):
There is no headroom for ISOs and lowering the volume does not change anything, even if that is a function of this SRC too. But it's not the full story. The SRC not only clips due to the overs but is completely overloaded, generating plenty of distortion all over the place as you can see below (5512.50Hz @0dBFS with 67.5 degrees phase shift):
We see the high level H3, typical of clipping (odd number), and plenty of unwanted high level spikes. This CD player will not like too hot masters, as the Teac VRDS 25x, or the EMT 982 that I previously reviewed and that use an ASRC too. All of this means that the interpolator in use does not have protection for digital overs, and it is the same effect at the digital output of the SMSL PL20, so you can't improve things with an external DAC.
----
Let's continue with the good old 3DC measurement that Stereophile was often using as a proof of low noise DAC. It is from an undithered 997Hz sine at -90.31dBFS. With 16bits, the signal should appear (on a scope) as the 3DC levels of the smallest symmetrical sign magnitude digital signal:
Wow, that is the best trace I've seen. Minimum disruption here meaning a very silent CD player of high resolution.
The ringing is due to the symmetrical reconstruction filter (both the SRC and the oversampling filter) and the Gibbs Phenomenon.
----
Other measurements (not shown):
The Dynamic range is the best that can be measured (unweighted) with the Audio CD.
Crosstalk was below what I can measure from the Audio CD at 100Hz and 1kHz, and a crazy low -128dBr at 10kHz. This might be the best measurements I reported.
Pitch error is a very small -3.5ppm (GPSDO corrected).
This CD Player is not gapless and will not properly decode CDs with Pre-emphasis.
----
Sorry no measurements of THD vs frequency as I had a software issue that I don't know how to fix at the moment.
----
As I did with the Sony CDP-597, I add a "max DAC resolution" measurement test. It is performed from a 999.91Hz sine @-12dBFS with shape dither (from Audacity). I restrict the THD+N span to 20Hz - 6kHz in REW not to account for the noise of the shape dither beyond 6kHz. I take the calculated ENOB and simply add 2bits to it (due to the -12dB attenuation, as 1bits=6dB). The potential maximum, when calculated from the digital WAV file, is 18.7bits under this test. A "transparent" DAC should achieve 18.7bits, ie 100% in this test.
Here are the results compared to others:
The PL20 is very close to the best in class, and from that perspective, this is a top performer...
SMLS PL20 - Testing the drive
What would be good measurements if the drive would not properly read a slightly scratched CD, or one that was created at the limits of the norm? The below tests reply to these questions.
Here are the results:
If this drive is slow, nothing prevents it from reading the most scratched CDs. These are best in class results. I could see some interpolation kicking off with 2.5mm gaps, but I could not hear anything.
SMSL PL20 - Digital Output (from Audio CD)
Ok, so you already know that this one does not output a "bit perfect" digital signal, since it is converted to 48kHz sampling rate. Nevertheless, this is my standard 999.91kHz @0dBFS:
You can recognize the distorsion I showed with the same test from the analog outputs. It is non-harmonic, and is the fault of the SRC that I already mentioned. This distorsion is very low (-115dBr in worst case) so it can be ignored.
The 3DC test is nailed too, of course, actually almost not as good as with the analog output (funny):
My ultimate proof of "perfect" digital output is when I reuse the intersample overs test at 5512.50Hz, with a phase shift of 67.5°, like I did for the TASCAM CD-200 review. This signal generates an overshoot of +0.69dB and so if the signal would be modified before being sent (by an ASRC for instance), it would show either a reduction of amplitude or we'd see some sort of saturation/increase noise/distorsion. And like I said, we have an SRC in the digital path so we are far from what's recorded on the CD:
That hurts...
Conclusion
The Sample Rate Converter, always active with the analog or digital outputs, is what limits this CD Player from being best in class.
Other than that, it is impressive considering the price and features.
I hope you enjoyed this review and I wish you a nice weekend!
This is a review and detailed measurements of the SMSL PL20 CD Player and Transport.
It was kindly sent to me by Aoshidaudio.com.
SMSL PL20 - Presentation
This one was released just before Christmas 2025, and is hosting 2 CS43131 DACs. The look is similar to the PL100 with a wider front display, so it's easier to know what track is being played from a distance. Its price is roughly 200$.
This new CD Player offers the below features:
- Plays audio CD, of course
- Balanced and unbalanced phones out, but on the back (see below)
- Volume control, active with digital output too
- USB input up to 24bit/96kHz, DSD64 (from data CD too)
- Bidirectional Bluetooth 5.3
- CD Rip direct to USB drive (not to a computer)
It can be powered from a a USB 5V/2A source (battery or phone charger). We also get 2 digital outputs coax and Toslink.
Important note: I received one of the first units produced, before it was publicly available, and I spotted an issue with volume control. I contacted Aoshidaudio right away and they provided me with a prototype firmware, in less than a week, which solved the issue. I guess this has been fixed on units that have been shipped later on, but in case you feel there's an issue with the output volume, feel free to contact me so I can provide you with more insights.
By the way, the volume control has 16 steps (from 0 to 15), and is active in digital and analog domains.
I measured each of the attenuation step (from digital outputs):
- 15 = 0dBFS
- 14 = -2.10dBFS
- 13 = -4.40dBFS
- 12 = -6.80dBFS
- 11 = -9.40dBFS
- 10 = -12.30dBFS
- 9 = -15.50dBFS
- 8 = -19.10dBFS
- 7 = -23.20dBFS
- 6 = -27.90dBFS
- 5 = -33.40dBFS
- 4 = -40.20dBFS
- 3 = -48.80dBFS
- 2 = -61.30dBFS
- 1 = -82.30dBFS
- 0 = -∞
User experience
As I'm now used to report, here are some elements about my user experience with this device:
- It is not gapless playback
- It takes up to 11 seconds to read the TOC of a CD and that is because it recalls last position
- Skipping a track is slow, and cumbersome to skip more than one
- FFW and REW are not available
- I could not hear any noise except when it goes from the last track to the first one
- It goes into sleep mode alone, which I like
SMSL PL20 - Measurements (RCA Analog out)
All measurements performed with an E1DA Cosmos ADCiso (grade 0), and the Cosmos Scaler (100kohms from unbalanced input) for analog outputs, and a Motu UltraLite Mk5 for digital outputs.
I am consistent with my specific measurements for CD Players, as I described them in the post “More than we hear”, and as I reported them for the SMSL PL200 review.
The SMSL PL20 outputs 2Vrms and the two channels match at 0.05dB (this is good). Phase is dead flat.
----
As usual, let's start with my standard 999.91Hz sine @0dBFS (without dither) from the Test CD (RCA out):
This is a very good result for a CD player even if the right channel suffers more H2 distorsion (the green spike that you see) which brings the SINAD down from 98.4dB to 95.8dB. SNR is already best in class for the Audio CD, even with that max digital level output
Let's try the same at -6dBFS:
Again very good result (worst channel shown in the dashboard, this time). We find again that little more H2 in the right channel, but at -105dBr, we can ignore it.
----
I usually have a look at any potential PS related leakage, and you saw it before, there are none, even if I zoom with a punishing 512k FFT length:
The few spikes you see come from the digital file, quantization errors (or rounding errors with 16bits). This is what I'd like to see with all CD Player.
----
Next is the bandwidth:
This is flat within -0.1dB. Note the small channel imbalance of 0.05dB. No need to ask for more, honestly.
----
Let's have a look at the job of the oversampling filter, with a wider bandwidth:
This oversampling filter is fully active at 26kHz, which is a bit late (I'd prefer 24khz), and so we can see aliases of the two test tones of the AES test that weirdly replicate at around 24kHz. The small rebound of the white noise trace at 24kHz is a second surprise.
These elements indicate heavy processing of the digital signal, my guess. Other tests should confirm.
----
Let's have a look at the multitone test that a lot of you like very much:
We get few unwanted spikes, but nothing of real concern. Can do better though.
----
Oh yes, the jitter test:
We get few spikes, not of concern, but surprisingly, they are not at equal distance from the fundamental. At this point, we shall suspect a resampling before conversion. The same test in digital domain (from the optical output) would confirm.
And indeed, not only my interface locks at 48kHz instead of the expected 44.1kHz, I get the same trace from the Toslink output:
So, we see side bands at 8.1k and 14.9k indicating a correlation between the initial 44.1kHz sampling rate and the resampled 48kHz output.
Indeed, the fundamental of the Jtest is at 44.1kHz / 4 = 11.025kHz
And 48kHz - 44.1kHz = 3.9kHz
And 3.9kHz / 4 = 0.975kHz
And 0.975kHz / 2 = 0.48kHz
And 11'025kHz + 0.48kHz = 11.5kHz
Conclusion: the side bands are centered around 11.5kHz as shown by the plot.
This of course means there is a Sample Rate Converter always in action. I suppose this is to tackle all different possible sampling rate inputs that this CD player can handle. The next test will tell us if this SRC appreciates inter-sample overs (generally not...).
----
Started with the Teac VRDS-20 review, and on your request + support to get it done (more here), I'm adding now an "intersample-overs" test which intends to identify the behavior of the digital filtering and DAC when it come to process near clipping signals. Because of the oversampling, there might be interpolated data that go above 0dBFS and would saturate (clip) the DAC and therefore the output. And this effect shows through distorsion (THD+N measurement up to 96kHz):
| Intersample-overs tests Bandwidth of the THD+N measurements is 20Hz - 96kHz | 5512.5 Hz sine, Peak = +0.69dBFS | 7350 Hz sine, Peak = +1.25dBFS | 11025 Hz sine, Peak = +3.0dBFS |
| Teac VRDS-20 | -30.7dB | -26.6dB | -17.6dB |
| Yamaha CD-1 | -84.6dB | -84.9dB | -78.1dB |
| Denon DCD-900NE | -34.2dB | -27.1dB | -19.1dB |
| Denon DCD-SA1 | -33.6dB | -27.6dB | -18.3dB |
| Onkyo C-733 | -88.3dB | -40.4dB | -21.2dB |
| Denon DCD-3560 | -30.2dB | -24.7dB | -17.4dB |
| Myryad Z210 | -70.6dB (noise dominated) | -71.1dB (noise dominated) | -29.4dB (H3 dominated) |
| Sony CDP-X333ES | -30.5dB | -24.8dB | -16.3dB |
| BARCO-EMT 982 | -32.7dB | -24.5dB | -16.3dB |
| TASCAM CD-200 | -73.5dB | -36.3dB | -19.7dB |
| Sony CDP-597 | -30.4dB | -24.7dB | -16.5dB |
| SMSL PL100 | -53.1dB | -31dB | -19.1dB |
| OPPO BDP-95 | -39dB | -28.8dB | -19.2dB |
| OPPO BDP-95 (vol -2dB) | -95dB | -97.5dB | -32.7dB |
| SMSL PL200 | -94.8dB | -97dB | -39.5dB |
| SMSL PL20 | -29.5dB | -23.8dB | -22.5dB |
There is no headroom for ISOs and lowering the volume does not change anything, even if that is a function of this SRC too. But it's not the full story. The SRC not only clips due to the overs but is completely overloaded, generating plenty of distortion all over the place as you can see below (5512.50Hz @0dBFS with 67.5 degrees phase shift):
We see the high level H3, typical of clipping (odd number), and plenty of unwanted high level spikes. This CD player will not like too hot masters, as the Teac VRDS 25x, or the EMT 982 that I previously reviewed and that use an ASRC too. All of this means that the interpolator in use does not have protection for digital overs, and it is the same effect at the digital output of the SMSL PL20, so you can't improve things with an external DAC.
----
Let's continue with the good old 3DC measurement that Stereophile was often using as a proof of low noise DAC. It is from an undithered 997Hz sine at -90.31dBFS. With 16bits, the signal should appear (on a scope) as the 3DC levels of the smallest symmetrical sign magnitude digital signal:
Wow, that is the best trace I've seen. Minimum disruption here meaning a very silent CD player of high resolution.
The ringing is due to the symmetrical reconstruction filter (both the SRC and the oversampling filter) and the Gibbs Phenomenon.
----
Other measurements (not shown):
- IMD AES-17 DFD "Analog" (18kHz & 20kHz 1:1) : -93.8dB
- IMD AES-17 DFD "Digital" (17'987Hz & 19'997Hz 1:1) : -97.5dB
- IMD AES-17 MD (41Hz & 7993Hz 4:1): -115.3dB
- IMD DIN (250Hz & 8kHz 4:1) : -88.7dB
- IMD CCIF (19kHz & 20kHz 1:1) : -96.8dB
- IMD SMPTE (60Hz & 7kHz 1:4) : -103.6dB
- IMD TDFD Bass (41Hz & 89Hz 1:1) : -124.3dB
- IMD TDFD (13'58Hz & 19841Hz 1:1) : -109.3dB
- Dynamic Range : 98.9dB (without dither @-60dBFS)
- Crosstalk: 100Hz (below -150dBr), 1kHz (below -150dBr), 10kHz (-128dBr)
- Pitch Error : 19'997.07Hz (19'997Hz requested) ie -3.5ppm
- Gapless playback : No
- De-emphasis compliance : No
The Dynamic range is the best that can be measured (unweighted) with the Audio CD.
Crosstalk was below what I can measure from the Audio CD at 100Hz and 1kHz, and a crazy low -128dBr at 10kHz. This might be the best measurements I reported.
Pitch error is a very small -3.5ppm (GPSDO corrected).
This CD Player is not gapless and will not properly decode CDs with Pre-emphasis.
----
Sorry no measurements of THD vs frequency as I had a software issue that I don't know how to fix at the moment.
----
As I did with the Sony CDP-597, I add a "max DAC resolution" measurement test. It is performed from a 999.91Hz sine @-12dBFS with shape dither (from Audacity). I restrict the THD+N span to 20Hz - 6kHz in REW not to account for the noise of the shape dither beyond 6kHz. I take the calculated ENOB and simply add 2bits to it (due to the -12dB attenuation, as 1bits=6dB). The potential maximum, when calculated from the digital WAV file, is 18.7bits under this test. A "transparent" DAC should achieve 18.7bits, ie 100% in this test.
Here are the results compared to others:
| CD Player model or DAC | Calculated ENOB (999.91Hz sine @-12dBFS with shape dither, THD+N span = 20Hz - 6kHz) | Percentage of max resolution achieved (higher is better) |
| SMSL PL200 | 18.7bits | 100% |
| OPPO BDP-95 | 18.7bits | 100% |
| SMSL PS-200 (from CD player) | 18.6bits | 99.47% |
| SMSL PL20 | 18.5bits | 98.93% |
| Denon DCD-900NE | 18.5bits | 98.93% |
| Onkyo C-733 | 18bits | 96.26% |
| SMSL PL150 | 18bits | 96.26% |
| SMSL PL100 | 17.9bits | 95.72% |
| Sony CDP-597 | 17.5bits | 93.58% |
| Onkyo DX-7355 | 17.3bits | 92.51% |
| Denon DCD-3560 | 17.2bits | 91.98% |
| Yamaha CD-S303 | 16.8bits | 89.84% |
| Revox B-226S | 16.8bits | 89.94% |
| Accuphase DP-70 | 16.6bits | 88.77% |
| Sony CDP-337ESD | 16.6bits | 88.77% |
| Teac VRDS-25x | 16.5bits | 88.24% |
| Marantz CD-73 | 14.9bits | 79.68% |
The PL20 is very close to the best in class, and from that perspective, this is a top performer...
SMLS PL20 - Testing the drive
What would be good measurements if the drive would not properly read a slightly scratched CD, or one that was created at the limits of the norm? The below tests reply to these questions.
Here are the results:
| Test type | Technical test | Results |
| Variation of linear cutting velocity | From 1.20m/s to 1.40m/s | Pass |
| Variation of track pitch | From 1.5µm to 1.7µm | Pass |
| Combined variations of track pitch and velocity | From 1.20m/s & 1.5µm to 1.40m/s & 1.7µm | Pass |
| HF detection (asymmetry pitch/flat ratio) | Variation from 2% to 18% | Pass |
| Dropouts resistance | From 0.05mm (0.038ms) to 4mm (3.080ms) | Pass |
| Combined dropouts and smallest pitch | From 1.5µm & 1mm to 1.5µm & 2.4mm | Pass |
| Successive dropouts | From 2x0.1mm to 2x3mm | Pass |
If this drive is slow, nothing prevents it from reading the most scratched CDs. These are best in class results. I could see some interpolation kicking off with 2.5mm gaps, but I could not hear anything.
SMSL PL20 - Digital Output (from Audio CD)
Ok, so you already know that this one does not output a "bit perfect" digital signal, since it is converted to 48kHz sampling rate. Nevertheless, this is my standard 999.91kHz @0dBFS:
You can recognize the distorsion I showed with the same test from the analog outputs. It is non-harmonic, and is the fault of the SRC that I already mentioned. This distorsion is very low (-115dBr in worst case) so it can be ignored.
The 3DC test is nailed too, of course, actually almost not as good as with the analog output (funny):
My ultimate proof of "perfect" digital output is when I reuse the intersample overs test at 5512.50Hz, with a phase shift of 67.5°, like I did for the TASCAM CD-200 review. This signal generates an overshoot of +0.69dB and so if the signal would be modified before being sent (by an ASRC for instance), it would show either a reduction of amplitude or we'd see some sort of saturation/increase noise/distorsion. And like I said, we have an SRC in the digital path so we are far from what's recorded on the CD:
That hurts...
Conclusion
The Sample Rate Converter, always active with the analog or digital outputs, is what limits this CD Player from being best in class.
Other than that, it is impressive considering the price and features.
I hope you enjoyed this review and I wish you a nice weekend!
Last edited:
