SMSL PA-X Stereo Amplifier Review

[classaistheway]

I agree. Amps are for listening to music not test tones. It's a shame it failed rather than shutting down but there's a disproportionate amount of ridicule being placed on an amp that probably won't fail under any normal use conditions.

 

[Old_School_Brad]

I agree. Amps are for listening to music not test tones. It's a shame it failed rather than shutting down but there's a disproportionate amount of ridicule being placed on an amp that probably won't fail under any normal use conditions.

And how exactly do you know that?

This amplifier’s performance is being evaluated in the context of every other unit Amir has tested -and will test -the vast majority of which handle this relatively undemanding test without shutting down. Keep in mind, this isn't even close to being as rigorous as the standard FTC testing, yet the unit still failed. The way it did points directly to a design flaw in the protection circuitry, which is the manufacturer’s responsibility.

Unrelated, but here are the obligatory poor analogies -use at your own risk:
Imagine a car manufacturer complaining about NCAP crash tests by saying, “Cars are made to be driven, not crashed.”
Or picture the hypothetical situation where a major tech company dismissing reception issues by saying, “You’re holding it wrong.”

Both sounds a bit silly, right?

 

[kyuu]

The way it did points directly to a design flaw in the protection circuitry, which is the manufacturer’s responsibility.

Yep. It's not a problem, IMO, that it went into protection during the test. The fact that it could not recover and basically became a brick is a big problem, though. It's not as though the conditions to trigger a protection circuit are unthinkable, that's why protection circuits exist.

 

[classaistheway]

Unrelated, but here are the obligatory poor analogies -use at your own risk:
Imagine a car manufacturer complaining about NCAP crash tests by saying, “Cars are made to be driven, not crashed.”
Or picture the hypothetical situation where a major tech company dismissing reception issues by saying, “You’re holding it wrong.”

Both sounds a bit silly, right?to

To take your analogy further, do you expect to live if you're stupid enough to drive into a wall at 200mph just because your car passed safety testing? That's the auto equivalent of letting an amp clip for extended periods with RMS power levels way beyond the point where it would start sounding bad.

Audio is not a sinewave and you will hear clipping on large swings long before RMS power gets to the level seen in this test.

I agree, the amp should not have failed permanently during this test but I maintain it's likely not an indication of how it will perform under real world conditions with a half observant operator.

 

[Old_School_Brad]

Audio is not a sinewave and you will hear clipping on large swings long before RMS power gets to the level seen in this test.

I agree, the amp should not have failed permanently during this test but I maintain it's likely not an indication of how it will perform under real world conditions with a half observant operator.

This is one of those debates that will likely never be settled.

You see the “FTC-like” test as too demanding -I see it as laughably easy. In my view, any properly designed amplifier should pass it without breaking a sweat. I continue to support the principles behind the FTC power tests and even believe the required duration should be extended.

That said, I do respect differing opinions on the matter.

But here’s the bottom line: Amir’s testing is consistent, which makes it useful for comparing amplifiers under identical conditions. And under those same conditions, this particular amplifier didn't fare well, while the vast majority of others handled the test just fine.

Given that, I think it's entirely fair to direct some criticism at the design.

 

[classaistheway]

I think you may not have been interpreting my message the way I intended. I agree with you about the test and I agree the amp should have failed it in a more graceful manner. A simple linear power supply with an accessible and appropriately rated fuse fails more gracefully than this did. Of course, I would like to see all modern amps pass the test.

All I was saying was that I don't think this test necessarily shows that the amp will be unreliable or problematic in every day use for playing music.

 

[Roland68]

For this kind of money, performance like this has pretty much never existed — but if there's a 1.5 dB drop at 20 kHz, then you think it's terrible The amp sounds fucking great, it's a best buy, and you just pass it by — congrats.

But you have to have a lot of blinders on for that. Personally, I find the price very high considering the power and measurements, especially for a manufacturer like SMSL, whose warranty is only available through specialist retailers and has no repair options.

Just a small selection of alternative amplifiers.

The NAD 2200 was better over 35 years ago and has significantly more power. Even at 8 ohms, more comes out than at 4 ohms with the PA-X. For that price, you can get two used NAD 2200s.

The Sabaj A30a has the same power, but better measurements, no load dependency, and is cheaper.

The 3E Audio A7 also has the same power, slightly higher max power, significantly better measurements, and is significantly cheaper.

AUDIOPHONICS AP300-S250NC €549, higher power, better measurements.

AUDIOPHONICS AP300-S500NC approx. same price, more than double the power at 4 ohms, almost 3 times the power at max power, better measurements.

 

[xanalog]

Well, it measured worse than amps 1/3rd the cost and died. Excuse me if I’m not lining up for it…

 

[Megadeaf]

I am happy with my dual A300 setup bit I got hyped for dual Pa x. Has anyone tested these in mono operation?

 

[Usatencu]

I m a happy owner of one stereo smsl pa x amplifier, matched with a tube dac and a class A preamplifier all of them to kef r3 meta. I m not sound engineer and i don't care about measurements, but this amplifier drop my jaw!!! My speakers never sound better. I had before also a topping pa7 plus with better measurements and some popular class ab amps, but none of them is comparing with this one! Sound it s so fantastic, just cannot push stop button, it s keeping me engaged now for hours. In conclusion, i m so impressed and now i m thinking to buy one more to run them in mono mode. I m listen music mostly in low levels volume, do you think i will have better sound quality in mono

 

[Guddu]

Thank you @amirm
Were you able to get “Power vs distortion @4ohm driven” before it broke?
Is it possible to get it if it was captured?

 

[Panelhead]

. I m listen music mostly in low levels volume, do you think i will have better sound quality in mono

No, you would never hear the difference.

 

[Alexx]

Have any of you had a chance to listen to it?

I'd like to buy it and use it as a power amplifier, using the Wiim Ultra as a preamp and managing all the sources (HDMI, Phono, Optical, etc.).

I can set the Wiim Ultra to a fixed output and use the SMLS PA-X remote to raise and lower the volume.

Do you think it's a good product?

I found this review online:

They speak highly of it, but I'm not sure I trust it.
Thank you very much.

 

[MaxBuck]

Have any of you had a chance to listen to it?

Listening to amplifiers is pointless. If they test well, they add and subtract nothing except sound pressure level.

 

[Alexx]

The problem is that the only test I've done is here on the forum, but the device burned out... I'm not sure if it's a good device or not.

It's spoken well of online, but I can't rely on people's personal tastes.

The Eversolo Amp-F2 might also be good; I'll see if I can find some tests.
Thanks.

 

[Lsi]

Hi all
Regarding this amp connected to kef ls 50 meta ,should i change the 8-ohm or 4-ohm speaker ?
Thanks shay

 

[Alexx]

I can't help you.

I have the same question as you about 6 Ohm speakers. I also asked the dealer, but he gave me a vague answer without specifying anything.

Another strange thing is that they told me that for best performance, it needs to be turned up to maximum and driven by a preamp (I have a Wi-Fi Ultra). This way, it has a more open and detailed sound, but that seems like nonsense.
Best regards.

 

[Lsi]

Thanks for you answer
I connect it with xlr to smsl su9 ultra without any preamp...

 

[Alexx]

Wiring it this way is the best.

Anyway, you can try both 8 Ohms and 4 Ohms; nothing happens.

This way, see what you like. If it distorts when you run it at 4 Ohms, set it to 8 Ohms.

That's what I've been told -

 

[Alexx]

@Lsi
I'm still waiting for mine. I placed my order, but it's not available for shipping yet (on Amazon for €645).

Have you tried yours? How do you like it?

I've read several reviews; they say it's an excellent product, perhaps a little too forward and bright on the high frequencies. They recommend pairing it with a suitable speaker.

You've encountered this "problem," which isn't actually a problem, but I imagine it's perhaps a characteristic of these Gallium Nitride power amps...
Thank you very much.