SMSL PA-X Stereo Amplifier Review

[amirm]

Any word from the company regarding the test?

The company didn't send it to me. Shenzhenaudio did. I have let them know about the issue.

 

[Sokel]

Fail of decent protections is a general fail these days.
All that amp has to present is that is GaN and nothing else.

Thanks Amir!

 

[ObjectiveSubjectivist]

I would rather take anything with PFFB (if considering class D amp) other than gan marketing stuff.

 

[Settembrini]

Thanks a lot for the review, great job!

 

[obsessive9119]

What would be the selling point of this vs a couple of Fosi V3 monos for 1/3 the price?

 

[amirm]

What would be the selling point of this vs a couple of Fosi V3 monos for 1/3 the price?

It produces nearly double the power at 8 ohm and looks a lot nicer.

 

[Old_School_Brad]

It produces nearly double the power at 8 ohm and looks a lot nicer.

And it keeps things much cleaner by having the power supply built in.

 

[obsessive9119]

It produces nearly double the power at 8 ohm and looks a lot nicer.

Hmm I was looking at the 4ohm power - 192 vs 208.

 

[daniboun]

The only GaN modules that hold up are the Orchard Audio ones

Measurements so you can compare

Starkrimson® Ultra Specs - Orchard Audio

Specifications and test results for our award-wining, state-of-the-art, Starkrimson Ultra 500W GaN audio power amplifers.

orchardaudio.com

 

[GXAlan]

Why wouldn’t you just get:

Yamaha A-S701 Stereo Amplifier Review

This is a review and detailed measurements of the Yamaha A-S701 stereo integrated amplifier with included DAC and Phono stage. It is on kind loan from a member and costs US $800. The A-S701 is one of the best looking amplifiers I have tested. Yes the controls are plastic unlike the glory days...

www.audiosciencereview.com

Not voting option for poor?

 

[pma]

Consumer audio is a fashion business.

 

[amirm]

Why wouldn’t you just get:

That's a much bigger box. You wouldn't put it on your desk where this would be comfortable there.

 

[Roland68]

The company didn't send it to me. Shenzhenaudio did. I have let them know about the issue.

Even though SMSL manufactures it, the RAW series is one of the products commissioned by Shenzhenaudio and distributed exclusively through Shenzhenaudio and its partners.

There are also other devices and product lines built for other distributors and retailers. This is why there are so many similar and redundant devices in the SMSL portfolio, not to mention Sabaj and Loxjie.

I think many users aren't even aware of this. Trademarks with "by SMSL" might have been clearer and more useful.
The purchase links on the SMSL website indicate which dealer/distributor the device belongs to.

 

[tomtoo]

Fuse inside?

 

[anphex]

Tbh looks like some "bulk part sale" Frankenstein. You can't tell me this was actually profoundly designed, even less my SMSL. This was probably a grab of lots of cheap parts and putting them together as good as possible for a buck. Now slap 500 % margin on that and you're good.

 

[Roland68]

Tbh looks like some "bulk part sale" Frankenstein. You can't tell me this was actually profoundly designed, even less my SMSL. This was probably a grab of lots of cheap parts and putting them together as good as possible for a buck. Now slap 500 % margin on that and you're good.

You have just described the global market for brown goods and white goods absolutely accurately, where there are very few exceptions.

 

[DavidEdwinAston]

This is a review and detailed measurements of the SMSL PA-X GaN based Class D stereo amplifier. It was sent to me by Shenzhen Audio and costs US $699.
View attachment 446326
The PA-X is gorgeously designed. It would look even better with the display on, had I not damaged the unit in testing (see below). A volume control IC is used allowing use of remote control:
View attachment 446327
I wish SMSL would include trigger functionality. The unit weighs a "ton" for its size, oozing feeling of quality.

If you are not familiar with my amplifier measurements, please watch this tutorial:

SMSL PA-X Amplifier Measurements
With balanced amplifiers, I start with that input:
View attachment 446329
Usually that produces better performance but not in this case as RCA does better:
View attachment 446330
Likely some kind of conversion is performed from balanced to unbalanced (due to volume control IC?), degrading performance. Either way, the PA-X scores well when it comes to noise and distortion:View attachment 446331
View attachment 446332
At the bottom is one of the first GaN based designed I tested. So not bad at all.

We can see the better noise figure for RCA input with our SNR tests:
View attachment 446333
View attachment 446334

Frequency response shows some load dependency. It is manageable but at the cost of 4 ohm roll off:
View attachment 446335

Crosstalk performance is a bit disappointing in the way it gets worse with lower frequencies. Usually it is the other way around as we see from our references:
View attachment 446336

Multitone performance is good:
View attachment 446337
Due to increasing distortion at higher frequencies, 19+20 kHz intermodulation distortion test shows worse performance (typical):
View attachment 446338

PA-X more or less meets is power specs:
View attachment 446339
View attachment 446340
View attachment 446341

There is a curious menu option to set the load to 4 or 8 ohm. It has no impact on the testing above, but does boost the power for 8 ohm:

View attachment 446342

At this point, I ran my FTC like power sweep where the amplifier is repeatedly pushed into clipping in order to generate the max power possible at 1%THD. The sweep starts from right and goes to the left:
View attachment 446343

Measurements stopped around 40 Hz. I looked at the amp and it had shut down. This is typical as many amps will complain and turn off. Alas, the PA-X would no longer power on. I waited a while until it cooled off and it still doesn't power on. I will test it again tomorrow but I suspect it is permanently damaged.

As I have said countless times, such stress times can damage amplifiers for no good reason. No one is going to push an amplifier into clipping for such extended amount of time as I did above. And at any rate, there is little industry awareness that such tests need to be passed. So to some extend, I feel responsible for damaging the unit.

Amplifier is stable on power up:
View attachment 446344

Conclusions
Other than the frequency response droop, the PA-X performs well and looks gorgeous while doing it. With the data we have, if it had not been damaged, I would have likely recommended it. As is, I am sitting here with a sense of regret.

My appreciation to Shenzhenaudio.com for sending the amplifier in for testing.

------------
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/

The service you perform for us.
The skill set you have in order to do this.
Your human failings.
Bad luck!
All in a short review.
Thank you so much amirm.

 

[Trdat]

I know there is the typical consensus 200 watts is enough for a standard bookshelf speaker, however my Troel Scanspeak 3WC clips under a NC252MP even without DSP.

I would expect the best way forward to close the deal with future amplifiers sales is a clean 300 watts at 8ohm at under $600.

This barely competes with the Hypex amps, no protection and essentially no differentiation.

 

[ErinPraline]

The only GaN modules that hold up are the Orchard Audio ones

Measurements so you can compare

Starkrimson® Ultra Specs - Orchard Audio

Specifications and test results for our award-wining, state-of-the-art, Starkrimson Ultra 500W GaN audio power amplifers.

orchardaudio.com

I'm only familiar with GaN in the USB-C charger market. Is its appeal a smaller footprint and less heat generation? I remember that being the marketing for the GaN phone chargers I've seen

 

[MCH]

I'm only familiar with GaN in the USB-C charger market. Is its appeal a smaller footprint and less heat generation? I remember that being the marketing for the GaN phone chargers I've seen

Yes it is amazing how much power can come out of those ridiculously small and completely sealed wall warts. I think there is a chance for very efficient very small power amps somewhere, maybe battery operated boom boxes or something. These gan amps have been around quite a while, I wonder where have they been used.