Wiim Amp Pro review: only for audiophiles

Wiim Amp Pro

MSRP $379.00

Score Details

“Wiim's upgraded streaming amp could be just what audiophiles are looking for.”

Pros

• Unbeatable price
• Slick all-in-one design
• Tons of audio settings
• Excellent sound quality
• Doby Audio support
• Google Cast, Spotify & Tidal Connect

Cons

• No Apple AirPlay
• No USB audio input
• May not sound better than the Wiim Amp

The original Wiim Amp impressed a lot of reviewers, myself included. As an alternative to much pricier products like the Sonos Amp, Denon Home Amplifier, or Bose Music Amplifier, the Wiim Amp delivers an impressive feature set, great sound quality, and a price ($299) that none of the big brands can beat.

So when Wiim announced its follow-up — the $379 Wiim Amp Pro — with better Wi-Fi and Bluetooth, improved audio quality, and Dolby Audio (but otherwise identical to the Amp), I questioned the need for such a device. Now that I’ve spent some time with it, I’ve concluded that for the average buyer, there is no need. In fact, thanks to one significant difference between the two models, you’re probably better off with the Wiim Amp instead of the Wiim Amp Pro.

But that doesn’t mean the Amp Pro should be ignored. Here’s why.

The streamer with an integrated amplifier

Before we get into the details, let’s quickly recap who should buy one of these devices.

The Wiim Amp, Amp Pro, and their competitors are network music streamers with built-in amplifiers. If you have a full sound system (speakers plus an amp or receiver) or you use powered speakers (e.g. Klipsch The Sevens), the Amp Pro isn’t for you. Instead, you want a network streamer without amplification. In the Wiim world, that means a Wiim Mini, Wiim Pro or Pro Plus, or the company’s flagship, the Wiim Ultra.

However, if you own a set of passive loudspeakers that you like, the Wiim Amp/Amp Pro are an all-in-one solution. They not only give you access to the entire world of streaming music, but they can also act as mini receivers, with several digital and analog inputs for other sources like TVs or CD players.

Just connect your existing speakers with traditional speaker wire and you’re good to go.

Wiim Amp Pro specs

Killer value

I’m guessing most of you just want to know if you should drop the extra $80 on the Amp Pro. If that’s you, feel free to skip to the next section.

For everyone else, I strongly recommend reading my in-depth review of the Wiim Amp. It gets into all of the features that make these products such an exceptionally appealing choice for digital music listening. From the flexibility of the connections (like the available HDMI ARC input and the subwoofer output with configurable crossover) to the superb Wiim app, which will prompt Sonos users to sigh nostalgically for the way things were — the Wiim Amp and Amp Pro represent unbeatable values.

I’m not going to say anything else here — everything you need to know about the Wiim Amp Pro is in that Wiim Amp review.

Everything, that is, except …

What’s the difference between the Amp and the Amp Pro?

Honestly, not much. Even the power output of the onboard amplifier is identical.

Physically, there are a few subtle differences.

The Amp Pro’s aluminum shell is only available Space Grey, whereas the Amp gives you a choice of Space Grey or Silver. The Amp Pro’s four rubber feet are thicker, which raises the height by two millimeters. It’s heavier too (4.5 pounds versus 4 pounds for the Amp).

According to the company, the Pro has a revised thermal management system that includes copper, aluminum, and a graphene heat sink.

Wiim got rid of the notchy, indexed movement from the Wiim Amp’s volume knob — the Amp Pro’s knob spins freely. I like the notched movement, but a free spin is more common on integrated amps and receivers, which is likely why Wiim changed it.

Finally, the Amp Pro’s 5-way binding posts have clear plastic sheathes over their collars, while the Amp’s are bare metal.

All of the Amp Pro’s upgrades are invisible:

• Updated DAC: the Pro shares the same 32-bit/384kHz ES9038 Q2M Sabre DAC as the Ultra, an improvement over the Amp’s ES9018 chip
• Texas Instruments TPA3225 amplifier with Post Filter Feedback (PFFB)
• Dual-antenna Wi-Fi 6 (6E is planned with a future update) and Bluetooth 5.3 with LE Audio
• Improved analog-out signal-to-noise ratio (SNR): 120dB versus 98dB on the Wiim Amp
• Improved analog-out total harmonic distortion (THD+N): – 105 dB (0.0005%) versus -92 dB (0.002%) on the Wiim Amp
• Dolby Audio decoding

Better audio?

In theory, those upgraded internals should result in better performance. In fact, Magnetic Magazine’s Will Vance waxes poetic about the Amp Pro’s Post Filter Feedback (PFFB) tech. “This isn’t just a buzzword — it’s what ensures you get crisp, clear, and load-independent sound. PFFB tech lets the Amp Pro handle anything you throw at it, whether you’re blasting the latest album in high-res or listening to a delicate jazz recording. The difference? You get an unfiltered, direct sound experience without distortion or color, even at higher volumes.”

Amir Majidimehr’s measurement-based evaluation of the Amp Pro’s frequency response in Audio Science Review appears to confirm that PFFB does help versus the Wiim Amp, especially when dealing with 8-ohm loads.

I’ll have to take Vance’s and Majidimehr’s word for it, because I simply couldn’t hear a difference.

For testing, I connected the Wiim Amp and Wiim Amp Pro to a simple A/B source switch. Attached to the switch’s speaker terminals were a set of Wharfedale Diamond 220 bookshelf speakers. Granted, they’re not the highest-end boxes in the world, but they’re still widely regarded as excellent speakers for the price.

I then began the semi-scientific process of playing my usual test tracks on each device at the same volume, flipping the A/B switch back and forth every 10 seconds or so — sometimes even faster. Keen observers will note that in the image above, I have the Wiim Amp and Amp Pro grouped within the Wiim app. While this is a valid way to play the same content on the two streamers simultaneously, it won’t deliver bit-perfect streams.

To make sure I was giving the two Amps the best possible material to work with, I streamed hi-res, lossless tracks from Qobuz and Apple Music with the players ungrouped too.

Now and then, I thought I detected a slight difference in presentation. Vocals might have been a hair smoother when coming through the Amp Pro, but I began to second guess these perceptions — they both sounded great to me. I repeated the A/B comparison for my wife and several of our friends, and none of them could distinguish between the sources.

Maybe it was the Wharfedales. Perhaps much better speakers would have revealed the nuances the Amp Pro’s upgraded internals and PFFB can supposedly deliver. Maybe it was the volume. I cranked both units well above 85% of their volume setting, but only for very brief periods to see if I could hear any distortion (I couldn’t). Perhaps if I had a really big room and listened at very loud levels for prolonged periods, the differences would become more apparent.

One area that might make a difference for some uses, is the Amp Pro’s ability to decode Dolby Digital. At the moment, with the Amp Pro serving strictly as a two-channel audio system, you’ll need to connect a wired subwoofer to benefit, and even then, the difference between Dolby Digital and stereo may be slight.

If Wiim ever adds the ability to use a set of rear channels to the Amp Pro (perhaps with a pair of Wiim Edition Audio Pro C10 wireless speakers), having Dolby decoding could create a really interesting 4.1-channel experience.

No AirPlay 2

Let’s assume for the moment, that my setup prevented me from hearing a difference and that those of you with great speakers and golden ears will be able to appreciate the Amp Pro’s improved specs. Now, before you go and drop the extra $80 for the Amp Pro, ask yourself this: Are you an iPhone user, and if so, do you like the convenience of Apple AirPlay?

If you answered yes, your decision just got harder. The Wiim Amp Pro doesn’t support Apple’s wireless music streaming protocol. The Wiim Amp, however, does.

Wiim hasn’t disclosed the reason for the Amp Pro’s lack of AirPlay — a weakness it shares with the Ultra — but it’s an omission that apparently can’t be fixed with a firmware update.

The absence of AirPlay 2 is the primary reason that only audiophiles should consider the Amp Pro. As a wireless streaming protocol, AirPlay 2 uses lossy compression. At a maximum bitrate of 328Kbps, it falls well short of the 1,411Kbps needed for lossless, CD quality streaming — let alone the much higher bitrates needed for hi-res audio.

In other words, if you’re committed to getting the most from your gear, you’ll generally avoid using AirPlay 2, even if it’s more convenient than other options. And with local streaming from USB, Google Cast, Tidal Connect, DLNA, and Roon compatibility, there’s no shortage of bit-perfect options.

Conclusion

So who should buy the Wiim Amp and who should get the Amp Pro? If your speakers are considered midrange, and if you have a small-to-medium-sized room, the Amp will serve your needs. Plus, you’ll get the added convenience of Apple AirPlay. I suspect most people fall into this category.

On the other hand, if you’re not fussed about the lack of AirPlay, and you believe your speakers (and your ears) could benefit from the Pro’s improved performance, $70 is a small premium to pay for potentially better sound.