SMSL A50 Pro Amplifier Review

[amirm]

This is a review and detailed measurements of the SMSL A50Pro stereo amplifier. It is on kind loan from a member and sells for US $96.00.

There is a white LED which shows the current volume level which I appreciate. The volume control is "overloaded" with menu and input selections but you can kind of figure it out. Back panel shows impressively level of functionality including a dedicated amplifier for the subwoofer!

You even get a remote control. The whole bit makes me think this is a platform made for soundbars given the HDMI and Toslink inputs. Let's hope it performs better than that.

SMSL A50 Pro Amp Measurements
As usual, I set the gain to 25 dB and tested with analog input:

Wow, this is exceptionally bad performance. We have distortion products that are nearly -60 dB and very high noise level resulting in very poor combo as represented in SINAD.

Fortunately things improve somewhat if you use digital input such as Toslink optical:

While general noise level and distortion peaks are reduced, we have a ton of interference. This level of performance lands the A50Pro in the "need work" category:

As noted, noise performance is poor:

Fortunately frequency response is not load dependent but is severely cut off, indicating input digitization at low sample rate:

I was hoping that feeding it digital input would allow wider bandwidth but it does not:

If anything, you will lose a bit of bandwidth into the audio band.

Power into 4 ohm is very limited:

I didn't see the point to continue as there are many better choices of amplification in this class but perhaps not with this level of connectivity.

Conclusions
Seems my guess was right that this is hardware platform designed for sound bar use with its HDMI and subwoofer analog output and such. In that class, measured performance is not critical but cost very much is. I get that this is a very competitively priced device but it needs to achieve a minimum standard of performance to fit in our vocabulary.

Needless to say, I can't recommend the SMSL A50 Pro. A cleaned up version of this functionality would be a nice thing to have, but not this.
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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

 

[amirm]

• Getting ten crossover frequency points adjustable for High-pass and low-pass each. Subwoofer's volume can set it separately, which perfectly can use well for different main speaker and passive subwoofer and build your real 2.1 speaker system.
• Passive subwoofer with adjustable volume and high power: The A50 Pro provides 100 watts of passive bass output power. lt effortlessly handles various speakers and scenarios, allowing you to adjust the subwoofer volume from S00 to S99 as desired.
• Multiple EQ presets: This digital amplifier features multiple EQ presets, allowing it to adapt to various music styles and provide a diverse listening experience. Additionally, it has bass and treble adjustments, with a customizable range of ±9 levels.
• Higher versatility Supports multiple devices: USB-C port supports driver-free use. HDMl (ARC) is compatible with most televisions and also equipped with optical input and AUX input. it's suitable for almost all audio connections.
• 12-month warranty, you can return the item or replace a new one if you have any problems.

 

[delta76]

I was expecting a Fine (happy) panther. Now my day is ruined /s

 

[respice finem]

Another example, why such tests are useful, regardless of brand and price.

 

[JSmith]

It is on kind loan from a member

Thanks to this member and for your continued testing Amir.

This is a bit of a mess in a number of areas... a shame SMSL can't up the game with their amps, as the feature set is good.

Pics;

JSmith

 

[Sokel]

Thanks to this member and for your continued testing Amir.

This is a bit of a mess in a number of areas... a shame SMSL can't up the game with their amps, as the feature set is good.

Pics;

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JSmith

No low price justifies such a mess.
Who soldered this thing?

Thanks Amir!

 

[welwynnick]

Thanks Amir.
And there I was, anticipating another rubber-stamped, glowing endorsement of SMSL. What a shock.
What's next - Topping?

 

[Mike123]

A common mistake when using the MA12070. It can be used without an output filter only when installed in active speakers with cable lengths up to 80 cm (page 24 of the PDF). Longer speaker cables definitely require an output filter. Trying to create an ultra-cheap amplifier doesn't really correlate with quality.

 

[obsessive9119]

Well that's disappointing but really does highlight what an amazing resource ASR is and the value Amir adds.

 

[audioje]

SMSL's dacs are great. But I haven't seen a good power amp yet.

 

[Bleib]

SMSL's dacs are great. But I haven't seen a good power amp yet.

AL400 might be the first. Hopefully Amir can test it

 

[DavidM1]

SMSL makes DACs that are among the best tested. Sad to see them sending out any amp this far below par.

 

[DanielT]

Thanks for the test Amir.

Question to SMSL: Why?

Another example, why such tests are useful, regardless of brand and price.

I agree.

 

[fordiebianco]

Blimey. How disappointing from such a well regarded brand.

 

[daftcombo]

A brand that provided us with a lot of good products shouldn't tarnish its image with such crap.

 

[GWolfman]

I was thinking their track record might have been enough for me to assume (at or near) a gold star at least. This product shows that this still can’t be the case. I was rooting for this one.

Thanks for the review @amirm.

 

[DSJR]

Limited bandwidth to 20kHz aside, this little box is the equal of many highly regarded high end amps, so what are you lot complaining about???

I'm being sarcastic above, by the way... Would it cost loads to refine it into better performance?

 

[Mike123]

Would it cost loads to refine it into better performance?

I modified the SMSL A100 on same chip. It's inexpensive. But a full modification is technically challenging. Making just the output filters is easy. They can be placed on the speaker cable. This will reduce high-frequency noise. However, most buyers are unlikely to want to purchase a kit for modification rather than a finished product.

 

[Multicore]

I would have thought that low noise would be important in a soundbar applications.

 

[Endibol]

We consider this (see below) very poor distortion performance for an amplifier, but fantastic performance for a loudspeaker! This starts to puzzle me more and more: why all this focus on electronics while our loudspeakers show so much more distortion...