This is a review and detailed measurements of the SMSL SA100 Stereo Audio Amplifier with analog and Bluetooth inputs. It was kindly sent to me by the member @lunagreenjp who is a distributor for SMSL. The SA100 costs just US $73.99 on Amazon including shipping.
Form the outside the SA100 matches its sibling, the M100 DAC:
Pushing the power button multiple times lets you select between Aux RCA in and Bluetooth. Pushing and holding the volume control lets you select Bass and Treble amounts. I was surprised that the unit had shipped with both set to max instead of zero.
The volume control works well and overall, you feel like you are getting more than the $74 price indicates.
Here is the back panel:
An external "laptop style" switching supply powers the unit. It is almost as large as the SA100 itself although not as thick.
I was pleased that my rather large and unwieldy banana speakers securely mated with the jacks on the SA100.
Overall, my impression is positive about the look and feel of this little, and I mean little, integrated amplifier.
The heart of the unit is TPA3116D2 class-D amplifier IC from Texas Instruments. I suspect it is made for Bluetooth speakers and such. In use the SA100 ran cool no matter how hard I pushed it.
Amplifier Audio Measurements
As usual, we start with our dashboard of a 1 kHz tone at 5 watts into 4 ohm load:
As is typical of amplifiers with volume control, one can get slightly different results depending on how you set the input level relative to volume control on the unit itself. The above is with volume control set to -1 I think.
High distortion dominates the output resulting in one of the worst numbers we have measured with respect to SINAD (noise+distortion relative to main signal):
Frequency response droops at both end some:
The sharp drop after 20 kHz tells me that input is perhaps digitized to provide tone control?
Signal to noise ratio "OK" for the class:
Measuring distortion and noise relative to output power with 8 and 4 ohm gets us:
Distortion sets it very early and climbs after that. Specified power ratings are quite inflated as is typical of these chip amps.
The sharp filter limit the measurement of harmonic distortion when we sweep frequency and power level:
The red curve for example is for 20 kHz but since we can't see any of its harmonics, it looks artificially low.
Here is the spectrum of a 1 kHz tone without any kind of filter (the above had filters):
Speaking of filter, even though I used an AES-17 filter to get rid of ultrasonic noise, the level was still so high as to confuse my Audio Precision analyzer. It would often not be able to capture the input signal properly.
Conclusions
If we measured the SMSL SA100 on an absolute level, it would rank horribly of course. But I don't think that is proper here. The SA100 costs so little and probably gets use in tertiary applications such as a workshop amp to drive cheap speakers you don't mind getting stolen or destroyed. And maybe for casual desktop use.
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As always, questions, comments, recommendations, etc. are welcome.
Today was election day. Just about everything on the ballot was another tax. While politicians are giving themselves raises this way, I thought why not me? So even if you have already donated, please consider donating again so that I can continue to enjoy my lavish lifestyle using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
Form the outside the SA100 matches its sibling, the M100 DAC:
The volume control works well and overall, you feel like you are getting more than the $74 price indicates.
Here is the back panel:
I was pleased that my rather large and unwieldy banana speakers securely mated with the jacks on the SA100.
Overall, my impression is positive about the look and feel of this little, and I mean little, integrated amplifier.
The heart of the unit is TPA3116D2 class-D amplifier IC from Texas Instruments. I suspect it is made for Bluetooth speakers and such. In use the SA100 ran cool no matter how hard I pushed it.
Amplifier Audio Measurements
As usual, we start with our dashboard of a 1 kHz tone at 5 watts into 4 ohm load:
As is typical of amplifiers with volume control, one can get slightly different results depending on how you set the input level relative to volume control on the unit itself. The above is with volume control set to -1 I think.
High distortion dominates the output resulting in one of the worst numbers we have measured with respect to SINAD (noise+distortion relative to main signal):
Frequency response droops at both end some:
The sharp drop after 20 kHz tells me that input is perhaps digitized to provide tone control?
Signal to noise ratio "OK" for the class:
Measuring distortion and noise relative to output power with 8 and 4 ohm gets us:
Distortion sets it very early and climbs after that. Specified power ratings are quite inflated as is typical of these chip amps.
The sharp filter limit the measurement of harmonic distortion when we sweep frequency and power level:
The red curve for example is for 20 kHz but since we can't see any of its harmonics, it looks artificially low.
Here is the spectrum of a 1 kHz tone without any kind of filter (the above had filters):
Speaking of filter, even though I used an AES-17 filter to get rid of ultrasonic noise, the level was still so high as to confuse my Audio Precision analyzer. It would often not be able to capture the input signal properly.
Conclusions
If we measured the SMSL SA100 on an absolute level, it would rank horribly of course. But I don't think that is proper here. The SA100 costs so little and probably gets use in tertiary applications such as a workshop amp to drive cheap speakers you don't mind getting stolen or destroyed. And maybe for casual desktop use.
------------
As always, questions, comments, recommendations, etc. are welcome.
Today was election day. Just about everything on the ballot was another tax. While politicians are giving themselves raises this way, I thought why not me? So even if you have already donated, please consider donating again so that I can continue to enjoy my lavish lifestyle using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/