WiiM Amp Pro Streaming Stereo Amplifier Review

[amirm]

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.

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.

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:

That is excellent performance, landing the WiiM pro in that very class in our rankings:

I am showing the non-pro version in dashed highlight, indicating good level of progress made:

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

Noise performance is excellent:

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:

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:

That results in less than stellar 19+20 kHz intermodulation distortion:

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:

Digital crossover works as expected:

Let's see how much power we have into 4 ohm load:

Output is limited to avoid clipping. 117 watts is plenty though for where this amp will get deployed. 8 ohm works the same way:

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:

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:

Amplifier is stable at power up:

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.

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

 

[amirm]

Reserved for @AdamG to kindly post the specs.

Manufacturer Specifications:

 

[kyuu]

Excellent performance. Whenever I have need for a 2-channel amp, can't see any reason to spend more than this, even ignoring everything else this little gem can do.

Now, Wiim, get on making a multichannel amp and/or full-fledged AVR pretty please!

 

[mcebrian]

I have to say that I am quite surprised with the adjectives used.

I like the product, and I see it has a ton of value, but I think we are behaving borderline hypocritical. With those “11bits” of IMD or those distortion figures for 10-15Khz other brands would have received only comments about bad engineering.

I don’t think it measures well enough for a community that has publicly cancelled products measuring better.

 

[kyuu]

I don’t think it measures well enough for a community that has publicly cancelled products measuring better.

Which products were "cancelled" with comparable measurements, exactly?

Edit: Perhaps you mean something like the Aiyama A70, which has an amp section that measures similarly, if not quite as well in most metrics, and which was cancelled? Oh wait, that received a golfing panther and was pretty universally praised it seems like?

 

[SiR]

@amirm thanks for the review and glad to see it receives your recommendations

Hope and wish to see your review of ULTRA at the earliest , which would help in deciding, whether to add it to my setup or not

 

[Sokel]

No FTC-like measurement?

Thanks Amir!

 

[kyuu]

No FTC-like measurement?

Ah yeah. I was hoping we'd see that measurement going forward so we could compare how amps respond.

 

[Sylvia]

Thanks a lot @amirm !!!
This has been awaited for a while

 

[mumadadd]

I kinda wish I had a need for this. Love the looks, performance and functionality. I have a WiiM streamer so I know the app is decent.

 

[Kegemusha]

Wow, just what I needed, I was waiting for this one. Thanks

 

[morillon]

to make a little system with two not too""temperamental "" libraries and a little sub... rather interesting now that the pffb to temper the particularity of these approaches...
"" too bad"" that not a correct headphone output which will benefit in addition to the peq...; -)

 

[Zek]

@amirm What is the USB port for?
Is it the DAC input?

 

[DSJR]

I'd just like to see hf distortion come down a bit to match the rest of it. Just a probably daft hunch, but I'm minded of metal dome tweeters taking off at 30 - 40kHz, often badly. Add the distortion harmonics and just possibly/maybe (maybe not), any intermodulation effects might come down into the audio band - maybe/possibly (maybe not).. The rest of it seems great and the price is very low really for a little box like this (my local audio salon now sells them as well - wonders never cease!!!), so forgive my excessive caution here.

 

[Haskil]

I have to say that I am quite surprised with the adjectives used.

I like the product, and I see it has a ton of value, but I think we are behaving borderline hypocritical. With those “11bits” of IMD or those distortion figures for 10-15Khz other brands would have received only comments about bad engineering.

I don’t think it measures well enough for a community that has publicly cancelled products measuring better.

Translate into percentages, the distortion of - 54 dB at 15 Khz, - 62 dB at 10 Khz and - 68 dB at 5 Khz... and you will undoubtedly be less disappointed.

Even if obviously, we would have preferred even better distortion figures that do not change with the amplified frequencies, as well as lower intermodulation distortion, even if here again the values are all below - 68 dB...

Many of yesterday's renowned integrated amplifiers and amplifier blocks, both transistor and tube, do no better. But are much more expensive.

If we look at what this Wiim Amp Pro gives for the market today, at the price it is sold for and if we take a time machine to see what we could buy as an integrated amplifier for the same amount of money in 1982, the year the CD was launched... You won't find much for a hundred dollars-euros...

I have just celebrated my 70th birthday and I am resolutely in the camp of "it was much less good and much more expensive before"...

 

[fordiebianco]

Nice one, @amirm . I continue to be impressed by this company, particularly by their ongoing software support for their legacy devices.

 

[Burnside]

@amirm What is the USB port for?
Is it the DAC input?

On the WiiM Amp, it supports usb media like a thumb drive or external ssd, as well as audio out to a DAC. I expect the Pro to do the same

 

[JeremyFife]

Thanks for this review Amirm, been looking forward to this.

For the likely intended uses (for me, that's avoiding a sound bar as a living room system with the TV as one source) it's pretty impressive. A fully featured integrated amplifier with great streaming, sub management, PEQ and basic room correction for a very reasonable price.
Measures very nicely indeed - slight drop-off at high frequencies and harder speaker loads are completely inconsequential (for the likely uses)

It's no powerhouse beast, able to shake your house ... but it's not for that. It's also new, so usual early adoption caveats apply - it's pretty nice though!

 

[Jimster480]

Performance is pretty decent, about 12-15db better than the Denon HS2 for around the same price.

 

[Romario]

Nice little amp that could replace my Naim UnitiQute for tv duties. However, the lack of a pre- out is fair at this price point but maybe something some might want.