WiiM Amp Pro Streaming Stereo Amplifier Review

[GXAlan]

The question is, how much does that rising distortion at treble frequencies matter? Is it at all audible? Aren't the second harmonics of 10kHz and 15kHz up at 20kHz and 30kHz, respectively?

Personally, I really enjoyed my 300B SET when it was in my care and that just had a 22 dB 5W SINAD. But there is a dichotomy where companies like PS Audio are criticized for poor measurements when it’s probably not audible, and sometimes the cheap amps with issues like this get a pass because it’s not audible.

That said, this post (and thread) may be helpful.

Post in thread 'THD above 10khz - why does it matter?'
https://audiosciencereview.com/foru...ve-10khz-why-does-it-matter.15356/post-545553

 

[Petrushka]

No, I have never created playlists for SiriusXM stations or Audible audiobooks. Maybe I'm missing something but I don't see why or even how you would do this.

I didn’t say I was creating playlists from Audible tracks.

Audible and XM are services I require that aren’t covered by Wiim (or Roon).

My argument is simply that there is nothing at any price that supports as many services seamlessly as Sonos. The reason people are hysterical about the app is because it is massively more comprehensive than any competitor.

 

[AdrianG]

So, i have a pair of kefs q150 and wiim amp would i notice an improvement with the wiim amp “pro”? Or my speakers are bottlenecking?

 

[Hart]

I certainly do. This level of performance for $3000? Probably more of a not terrible. This level for $380? Yeah top vote for sure.

Can't speak for everyone, of course. There are certainly some people for whom the fact that this is cheap and small is in fact a negative mark. Can't be a real amplifier if it's not big and expensive.

On the other side of the spectrum, when you see a $17,000 AVP that is good, does what it is supposed to...do you drop down a vote because it is over-priced?

 

[kyuu]

On the other side of the spectrum, when you see a $17,000 AVP that is good, does what it supposed to...do you drop down a vote because it is over-priced?

For $17k, that AVP better make me coffee in the morning and butter my toast in addition to being the most absurdly good performing and good looking AVP possible. Merely doing what it's supposed to do won't cut it for me.

 

[regan]

On the other side of the spectrum, when you see a $15,000 AVR that is good, does what it supposed to...do you drop down a vote because it is over-priced?

Great point. The price factor should be considered separately. Or maybe even completely left out - people can see themselves the price and evaluate their own "personal final score" based on their personal budget.

 

[Hart]

For $17k, that AVP better make me coffee in the morning and butter my toast in addition to being the most absurdly good performing and good looking AVP possible. Merely doing what it's supposed to do won't cut it for me.

For 2k you can get a well behaved Denon receiver with pre-outs. With the leftover you can get a Wolf stove, a Bosch dishwasher, a nice LG fridge, a Miele coffee maker, a Breville toaster, and an awful lot of coffee and bread.

 

[kyuu]

Yeah but none of that stuff will make the coffee and butter the toast for me while I'm sitting there listening to my tunes.

 

[GWolfman]

HDMI ARC (I still can't test this)

@amirm What do you need to test this? Hopefully it’s not a license or module for the AP…

 

[shuppatsu]

Great point. The price factor should be considered separately. Or maybe even completely left out - people can see themselves the price and evaluate their own "personal final score" based on their personal budget.

It's a community rating. Let the members of the community decide individually. Or let the community collectively decide on a rubric. But I will always consider price as part of my own rubric, and I think most people do. Otherwise the Chord DAVE would rate highly.

An extremely expensive piece of gear could of course receive a "Great." It could have tremendous functionality, beautiful design, stunning build quality, and the kind of engineering that evokes wonder and awe. But one slip up and boom it's "Fair."

 

[shuppatsu]

@amirm What do you need to test this? Hopefully it’s not a license or module for the AP…

The module isn't compatible with his AP. He'd need to get a whole new analyzer.

 

[amirm]

@amirm What do you need to test this? Hopefully it’s not a license or module for the AP…

The AP route is out of the question since I have to get a new AP just to get that option.

I have bought a TV with ARC support. I am hoping I can feed it PCM over HDMI and have it generate ARC. The challenge is figuring out where to put the big display in my lab. Then I can test it.

 

[Ralph_Cramden]

The AP route is out of the question since I have to get a new AP just to get that option.

I have bought a TV with ARC support. I am hoping I can feed it PCM over HDMI and have it generate ARC. The challenge is figuring out where to put the big display in my lab. Then I can test it.

Would this work?

Sonos Optical Audio Adapter

Optical digital audio to HDMI adapter cable

www.crutchfield.com

 

[amirm]

It might. Some people seem to complain that it doesn't work. Let me see if I can get one to try...

 

[amirm]

Just ordered it from SONOS....

 

[MyCuriosity]

One, as pointed out, this is the Wiim Amp Pro that isn't in the sales channel yet. You must've had the Wiim Amp (not pro).

Two, even with the Wiim Amp, it's unlikely there was any real difference assuming you were using it with the same speakers in the same environment with everything in the same position.

The only way a difference may have actually been there is if your speakers have >8 ohms impedance above 5000Hz or so, where they could interact with the amp's load dependency to elevate the treble a bit. But since the Wiim Amp has built-in parametric EQ, you could just use a shelving filter to compensate.

True, it was not the pro. To be honest the amp sounded bright and distinctly different to my Yamaha. Using EQ to compensate a deficiency is a way to work around but not something i would do. This amp is massively hipped for a very mediocre performance.

 

[MyCuriosity]

We’re discussing the WiiM Amp Pro here - I don’t believe you bought one from Amazon but its predecessor the basic WiiM Amp.

True. Still, don't expect any difference between the models. The one i got was massively hipped only to be returned. It is what it is, a cheap and affordable little amplifier. Calling it state of the art with a golfer panther is a stretch.

 

[Descartes]

This is a review and detailed measurements of the WiiM Amp Pro networked streaming stereo class D amplifier. It was sent to me by the company and costs US $379.
View attachment 394860
The package is minimalistic in nature and matches the "non-pro" version of the amplifier. The volume indicator is that set of LEDs. They are modulated though to show partial levels with dimming which is nice. The included app is quite sophisticated with many features which is one of the key differentiators for the company products. This revision adds PFFB (post filter feedback) which should do away with the load dependency of the non-Pro version.

Back panel shows nice inclusion of HDMI ARC (I still can't test this) and sub/mains output which actually works since you can apply filters to both.
View attachment 394866
Digital inputs are in the form of streaming and Toslink. Nice to see inclusion of power supply which is rare in this price/power class.

If you are not familiar with the measurements that are about to follow, please watch my tutorial on testing power amplifiers:

WiiM Amp Pro Measurements
Let's start with toslink input and our usual 5 watt output of 1 kHz tone:
View attachment 394868
That is excellent performance, landing the WiiM pro in that very class in our rankings:
View attachment 394870
I am showing the non-pro version in dashed highlight, indicating good level of progress made:

View attachment 394871

Analog input is digitized so doesn't have the same performance but should be good enough for a turntable and such:
View attachment 394872

Noise performance is excellent:
View attachment 394873

Even at 5 watts you easily clear the hurdle for 16 bit audio which many at much higher cost amplifiers fail at.

Let's get to the main test, which is frequency response:
View attachment 394874
We see peaking but it is outside of the audible band and at any rate, shows essentially no difference with the two load impedances. PFFB works!

Multitone performance is very good up to lower treble but then it rises some:
View attachment 394875

That results in less than stellar 19+20 kHz intermodulation distortion:
View attachment 394876
Fortunately there is zero content out there with full amplitude 19 and 20 kHz tones so practical impact is nill.

Crosstalk/channel separation is excellent:
View attachment 394877

Digital crossover works as expected:
View attachment 394878

Let's see how much power we have into 4 ohm load:
View attachment 394879
Output is limited to avoid clipping. 117 watts is plenty though for where this amp will get deployed. 8 ohm works the same way:
View attachment 394880
Keep in mind that most speakers have 4 ohm impedance in low frequencies where there is most demand for power.

Changing frequencies highlights the rising distortion with frequency yet again:
View attachment 394881
Ability to produce the same power at 20 Hz is impressive for such a compact design.

Reactive loads are handled well as long as you stay at 4 ohm and higher:
View attachment 394882
View attachment 394883

Amplifier is stable at power up:
View attachment 394884

Sorry, forgot to capture thermal image. The package insulates the insides anyway so wouldn't be very accurate.

Conclusions
Just about every measurement has subjective assessment of "excellent" showing the company has paid attention to all aspects of the design. It is in every way improved over the original version which warms my heart. Functionality is top notch with streaming and sophisticated app support. Price is quite reasonable for all this functionality, power and performance.

I am happy to recommend the WiiM Amp Pro.

P.S. Yes, I have the Ultra version as well. Hope to test that soon.

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As always, questions, comments, recommendations, etc. are welcome.

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Thank you Sir! It’s unfortunate it does allow you to use Airplay 2.0!

Some nice I have Apple Music, I will keep the original for now until the pro gets Airplay 2.0

 

[Haskil]

.20%, .08%, and .04%. Audible or not, that translates right into "not good" by any reasonable metric. It also suggests it is prone to IMD, which in fact it does exhibit. Audible? I'll leave that for someone else to judge. But as an amplifier it's not impressive. This is objectively bad, and in a Class AB would indicate no feedback or a very poor implementation. This isn't Class D done well. It's mediocre technical performance (which is exhibited by many of these chip amps) in a lightweight, small package. Meh. I'll take a Fire HD 10 tablet on a charging stand with a USB DAC hooked to amp of choice over this, thank you very much.

I wrote the following, which you ignored in your reply:
“Of course, we would have preferred even better distortion values, which do not vary with amplified frequencies, as well as lower intermodulation distortion, although again the values are all below -68 dB...”

- 68 dB is 0, 039 %

- 54 dB at 15 Khz : 0,2 %
- 62 dB at 10 Khz - 0,08 %
- 68 dB at 5 Khz : 0,04 %

[URL scroll down=“true”]https://sengpielaudio.com/calculatrice-thd.htm[/URL]


And also:
“Most of yesterday's reputable integrated amplifiers and amplifier blocks, both transistor and tube, don't do any better. But they're a lot more expensive.

And finally this:
“If you look at what this Wiim Amp Pro gives to the market today, at the price it's sold for, and if you take a time machine and see what you could get as an integrated amplifier for the same price in 1982, the year the CD was launched.... You can't find much choice for a hundred dollar-euros...”

And the problem with measured defects is knowing, when you take your eyes off your computer to check whether a device is in the blue, green, orange or red, and start listening to music, whether or not these undisputed objective defects are audible, under what conditions and in what proportion. This is important in real life. And it's no mean feat. I'm a convinced objectivist, attached to the quality of engineering put into products, but like many ASR readers I'm also a music lover, a pragmatist. And I've noticed that many of us own one of those little Class D amps with perfectible performance. We knew it when we bought them, and we don't suffer when we listen to music with them. We know we're not talking about a Purifi, a Nilai, an NC 500 from Hypex or any of those excellent Class D amps whose engineering is far more advanced than the amplification part of the little Wiim Amp Pro we sometimes own.

So yes, I'd prefer, as I wrote, even better performance, but I'm still going to buy one to put under my TV. And I agree with those who have spoken here that these distortion rates are in frequency zones and at levels where they won't be audible when listening to music or watching a film or program.
This is undoubtedly why ASR readers voted as they did, why Amir commented on his test in the way he did, and why so many others followed his example.

 

[morillon]

multitons ap32 in....4ohm...
would be interesting under 8 16 32 ohms it seems to me...( nid too?)
( not to mention complex loads, in this case we cannot stick to a max of 8ohms in the observations...especially since the impedance is rarely at its lowest on the tweeters...on the contrary)
;-)

I repeat myself but if used in reality often with the TV... the latency is really observed closely...(?)