Tuesday 1 August 2023

REVIEW / MEASUREMENTS: AIYIMA A08 PRO - TI TPA3255 Class D amp with AAC/LDAC/AptX Bluetooth input. On "giant killers" and "CHEAP" amps. Goodbye TIDAL MQA.

Over the last while it has been interesting checking out some TI TPA3255 "PurePath" chip Class D audio amplifiers such as the Fosi Audio TB10D [Upgraded] and AOSHIDA A7.

As you can see in the image above, I've got another one to put on the test bench for a look and listen - the AIYIMA A08 PRO (currently <US$130). Depending who you read/listen/watch, you'll see supporters who like the amp, sometimes calling it a "giant killer" of sorts, such as this blog post, or there are detractors like Andrew Robinson who seem to think these kinds of amps are only good in the nearfield and below 60dB SPL (see from 10:30). We'll talk about this below. :-)

As usual, let's start with a peek at what you get for a low price...

The amp arrived in a simple brown box with a few items like instruction pamphlet, an AIYIMA sticker, and power supply with cable (in my case for North American plugs):

The switching external power supply is relatively beefy:

Rated at 36V/6A, here's the company's table listing expected output based on power supply characteristics:

As with many manufacturer specs sheet, we're often not sure what amount of distortion these number are quoted for. Unless clarified, assume something like 10% THD!

Assuming the power supply rating is trustworthy, it should perform a bit better than the 32V/5A supplies which were what the Fosi Audio TB10D and AOSHIDA A7 were supplied with. We'll see whether this amp can provide a bit more juice in the measurements later.

As you can see, the amp chassis has a distinctive dip in the middle which is meant for the AIYIMA T8 tube Preamp, with headphone amplifier to sit in. The dual assembly would look like this:

Yeah, I guess that would keep the footprint small and could look alright on a desktop computer setup. Here's a look at the back of the amplifier:

Notice the small 3.5mm phono auxiliary output which could be used to feed an active subwoofer (with crossover control) for a 2.1-type setup. There are the two RCA single-ended inputs, and an antenna for Bluetooth 5.1 audio. The wireless chip is the Qualcomm QCC5125, quite a capable little device that can handle the full range of aptX Adaptive, LDAC, AAC, and SBC codecs. Speaker binding posts are of reasonable quality but in keeping with the price, is not as sturdy as they could be.

The box is metal, measures a compact 6.25"x5.25"x1.5" without antenna with a weight of 1.5lbs (~700g). No complaints about chassis ruggedness.

Here she is in use sitting on top of a couple other Class D amps - the AOSHIDA A7 and my Hypex nCore NC252MP.

Size is about equivalent to the AOSHIDA A7 including similar sized, responsive VU meter. Be mindful that the meter is linked to the left channel only. I see it as mainly decorative but do keep an eye to make sure the meter doesn't get into the red zone which suggests the input level is approaching the clipping point.

Turn the volume knob counterclockwise all the way to switch OFF/ON. Notice there's a red light around the volume ring in the image above which means it's using the RCA input. When Bluetooth is connected, the light turns blue. Bass and treble knobs are self-explanatory and I'll measure the effects. Keep it at the 12 o'clock position for flat frequency response. The volume knob is smooth with nice resistance. Bass and treble controls have a pleasant, finely indented feel.

As with other TI TPA3255 Class D amplifiers I've tried, the box barely gets warm when playing music at normal levels.

Let's put this thing on the test bench and see how it performs. For testing, I'll be using a combination of my Linear Audio Autoranger with the RME ADI-2 Pro FS as measurement ADC. I'll use the Beelink SER4 4700U computer for test signal & data collection with the Topping D10s as high-resolution single-ended signal generator (connected to Intona USB isolator to avoid ground loop risk).


Without further ado, let's have a look at some data. Unless stated otherwise, I'll leave the Bass and Treble knobs to 12 o'clock. Maximum gain on the amplifier is measured at +28dB.

Here's a 1kHz sine wave, 1Vrms level, left and right channels on the oscilloscope:

Channel balance is excellent. We can easily see the high-frequency switching noise in the waveform as expected for a Class D device without filtering applied. Let's have a look using the oscilloscope out to 1.2MHz to identify the frequency of that noise:

Looks like a pretty clean ~460kHz switching noise. This is typical for TPA3255 chip amps which will be attenuated with a bit of inductance in your system.

Here's the damping factor and output impedance using a 4Ω load:

While there's some slight variation with each manufacturer's amp, what we see above is similar to other TI TPA3255-based devices. Output impedance increases (damping dips) from about 1kHz up and it's around 1Ω by 20kHz. As with others, average damping factor into 4Ω across the audible frequencies is around 30-40x which is totally fine and will not lead to much frequency response variation using typical loads until around 10+kHz.

Let's confirm this with frequency response measurements using various loads including my "standard" Sony SS-H1600 speaker for these measurements - note the "zoomed in" Y-axis of only 8dB range in the graph:

Notice a similar pattern we've seen with other TI TPA3255 amplifiers with that load-dependent variation at higher frequencies. This amp is quite "flat" into a 4Ω load but there tends to be upper treble accentuation with the higher 8Ω load and the Sony speaker. The Y-axis is tight, so these are in fact small variations, only +1dB with the 8Ω load at 20kHz.

For completeness, here's the frequency and phase into 4Ω:

No problem with the phase response at "flat" EQ settings.

While I have not really noticed an issue, I've heard that some listeners might experience a "harshness" with the high end not just with TI chip amps but also just in general folks claiming to hear this with Class D devices. If we think this might be related to the slight accentuation of the treble when paired with higher impedance speakers, we can apply the treble control, let's "tune" this down a little bit:

A slight reduction of the treble by just a couple tiny "clicks" as in the picture results in about 0.5dB lowering of the 20kHz response which gets it a little flatter into 8Ω but will droop the 4Ω response. Have fun with playing with the EQ settings depending on your speaker; maybe bright speakers with tweeter break-up resonance close to 20kHz could benefit from more fine-tuning.

Realize that in reality, when we connect speakers like the Sony above, there will be more complex fluctuations and things are not as simple as aiming for a flat response into a 4/8Ω load. Regardless, the complexities are likely not going to result in massive changes given the reasonably low output impedance.

Here's what the Bass and Treble knobs do if we examine the limits:

For the graph above, I normalized the curves to 0dB at 1kHz and varied the Bass and Treble knobs to maximum amounts. Basically what we're seeing is +/-6dB in the high frequencies, and +/-13dB in the low end. This is about the same as the tone controls of the Fosi Audio TB10D [Updated].

I had a quick look at stereo crosstalk examining the amount of seepage of 0dBFS 300Hz and 4kHz signals from one channel to the other and see less than -90dB crosstalk on average - excellent.

Let's now move on to the power vs. distortion graphs to see what we can get from this little amplifier with its stock power supply - as usual, tested with 4Ω and 8Ω loads.

Up until clipping, THD remains at most down at -70dB or 0.03%.

As mentioned above, this amplifier has a higher rated power supply (36V/6A) than the other TI TPA3255's I've tested so far and indeed we can see higher output using my usual "hi-fi" threshold of 0.1%/-60dB THD+N achieving 90W into 4Ω and 55W into 8Ω. (The 0.1% threshold selected based on empirical results of the blind test here awhile back.)

While staying below THD+N -60dB, notice that this amp tends to have an increase in 2nd order harmonics above 2Vrms which results in that rise in THD relatively early compared to something like the AOSHIDA A7.

Looking at the stepped sine results, linearity is very good:

Output level keeps track all the way down to about -108dB at which point it derails by 0.5dB.

Let's double check the THD+N across audible frequencies (at 2Vrms into 4Ω) to make sure it looks reasonably well controlled:

Looks good. Total distortion remains flat throughout the audible frequencies. Notice that the 3rd harmonic tends to rise from about 1kHz. Most of the distortion is low-order 2nd and 3rd harmonics and should not be objectionable.

Time for some high resolution 1kHz THD+N FFTs; my "standard" is 2V into 4Ω (1W), both left and right channels driven:

Notice that there is some asymmetry between the distortion characteristics of the 2 channels even though I'm using the same ADC and resistive load. This is typical so long as the results are not wildly different. I wondered if this asymmetry might have anything to do with the left channel being connected to the VU meter. Regardless, we're looking at THD+N around -81dB at 1W into 4Ω. This is in-line with other TI TPA3255 amplifiers.

Using a more complex signal, here's the Triple Tone TD+N using 48/960/5472Hz components, again as usual, both channels driven:

Average Triple-Tone TD+N of -84dB (~2Vrms into 4Ω or ~1W) is very respectable especially when you consider that this is a <US$150 amplifier capable of quite a good amount of power as well! As you can see, all the harmonics and intermodulation products are below -80dB from the primary tones.

And finally, let's use an even more complex tone, the 1/10 Decade Multitone 32 described previously; let's mix it up with output levels at ~2V into 4Ω (~1W), and ~6.3V into 8Ω (~5W):

We're seeing better than -70dB distortion-free range from the complex multitone peaks within the audible frequencies which again is indicative of high-quality audio playback (just think about the noise floor in your room and how much dynamic range you actually need).

For the 8Ω measurement, I ran it longer with 32 samples averaging and kept it running for 10 minutes to make sure I catch any elevated noise peaks (red) found during that time. As you can see, there are no surprises, the amplified complex test signal remained clean over time.


Let's not spend too much time here. To be honest, an amplifier that hits the objective bases including full and relatively flat frequency response, low distortion, and good dynamic range consistent across a battery of modern tests will perform as expected playing music. IMO, subjective evaluations of sound quality are highly injected with the listener's imagination; better to listen for oneself and enjoy the music rather than spending too much time reading/listening to the opinions of others.

In the last while, I've been spending time exploring the massive expansion of multichannel/Atmos content that is available out there now thanks to the drive towards "Spatial Audio" and "immersive" sound. IMO, this has been the most significant step towards providing new experiences for music lovers in decades. The nature, production, and playback of music is shifting significantly, and I believe for the better.

No, it's not that we did not have multichannel content before (since the 1970's we've had quadrophonic sound and discrete 5.1 since the early 2000's), but we're at the point now where finally, in some genres like pop and modern rock, the catalogue of multichannel/Atmos mixes is getting substantial. Thank you Apple, Tidal, Amazon, and Dolby for making the tools and policies needed to expand the mixing techniques and creative options. This is IMO what leadership looks like.

To put it through its paces, I ran this AIYIMA amp as my front channels from the analog pre-outs of the Yamaha RX-V781 receiver switching out between this and my "high-value/quality" reference Hypex nCore NC252MP amplifier. Output levels were equilibrated between the amplifiers.

I listened to a wide genre of material - some lossless 5.1 multichannel classical from Qobuz (as discussed last time), Joe Haisaichi's soundtrack material, pop stuff like some Ariana Grande / Ed Sheeran / Olivia Rodrigo, progressive rock like Pink Floyd / Roger Waters, rock like Kiss / Rolling Stones, some jazz and blues like Miles Davis / Joe Bonamassa (the album Time Clocks [2021, DR9] is very cool).

[By the way, if you like Joe Bonamassa's work, check out the BluRay concert Tales of Time (2023, DR12, TrueHD 5.1 multichannel) which is well done with good surround immersion.]

For completeness, I also listened to some 2-channel stuff comparing the Hypex and AIYIMA with quick speaker cable and interconnect switches as well.

While not blinded, the best I can say is that the difference is so minimal between the AIYIMA A08 PRO and the Hypex nCore NC252MP that it really doesn't matter; I can easily enjoy both of these playing at normal listening levels (~75-85dB SPL average) driving my Paradigm Signature S8 v.3 front speakers.

Yeah, I still have a bias towards the Hypex NC252MP with a subjective sense that it sounds a bit smoother in the higher frequencies. This is minimal though and I don't believe I would be able to notice a difference without some quick A/B switching.

"Clean" amplifiers that measure with low distortion and noise (if we want to put a number on it, say triple tone TD+N at 1W into 4Ω of better than -70dB) IMO will sound much more alike than different assuming there's nothing remarkably anomalous with output impedance / damping factor, and the frequency response itself. I personally don't see a need to get too excited about whether an amplifier is Class D, or A or AB if in general the measurements check out fine and the sound is clean. All things considered, it would be wiser to spend time optimizing the speakers/room and perhaps adding DSP correction if an audiophile seriously wants to make a meaningful improvement than spending too much time on amplifiers.

When differences are so minute with modern "hi-fi" amplifiers regardless of price these days, we're simply more free to sit back and enjoy the music.


Alright audiophiles, here's the summary graphic:

It's good. The AIYIMA A08 PRO with its more powerful switching supply can provide up to 90W into 4Ω and 55W into 8Ω loads while keeping THD+N below -60dB/0.1% than the other TI TPA3255 amps I've tested thus far. At 1W into 4Ω, distortion is at a very respectably low -84dB using the triple-tone signal. And the frequency response is reasonably well controlled through most of the audible range although be mindful of those high frequencies >10kHz; there is a treble control that one can use to finesse the sound.

Looking at the fine details, we see that THD does increase a little more than similar amps (like the AOSHIDA A7) above ~1W (both 4 and 8Ω). I still don't think it's a problem because this is all <0.1% total distortion and since this is low-order stuff, maybe some listeners might even have a preference to that extra "detail" from added 2nd and 3rd harmonics. :-) 

Given that the AIYIMA is the third TI TPA3255 Class D chip amp I've measured, I must say that across the board, this inexpensive, high-efficiency amp chip technology works well for moderate-power amplifiers that many audiophiles and music lovers will enjoy in the home. As such, these amplifiers represent a level of sonic performance at the $100-150 price point as a kind of benchmark which I would hope more expensive products should exceed.

Although I obviously cannot vouch for longevity of these inexpensive amplifiers or manufacturer quality control, what I can measure and hear represents an astounding value; an important reminder of just how good sound quality can be without in any way "breaking the bank". As usual, I have no issues with audiophiles spending thousands and thousands of dollars on amplifiers. That's totally fine, just realize that for "high fidelity" playback, the base quality is already very high so I would make sure something more expensive at least can perform up to par and represents acceptable value in the construction, materials, features, and whatever "non-utilitarian" benefits one might also seek.

It has been years I think since publishing on Bluetooth audio measurements. Let me see if I can examine Bluetooth quality of a device like this over the next little while since it accepts multiple codecs.


To end, I thought it would be fun addressing how in audiophilia we often talk of finding products that are "giant killers", and on the other extreme a tendency to devalue certain products, especially those viewed as "cheap". All kinds of opinions on blogs, magazines, and of course these days, YouTube videos out in cyberspace...


At the start of this post, I mentioned the fascinating blog post from a Hong Kong writer about the AIYIMA A08 PRO written in October 2022 (and other contributors to the page). Amazing that for the writer, with the AIYIMA: "I was forced to use my best setup to squeeze out its maximum potential and I felt that it would go from strength to strength if paired with good associated equipment". From a guy with an interest in more expensive gear driving his Dynaudio Crafft studio monitors (86dB/2.83V/m, rated 4Ω). The article certainly reads like he sees this <US$150 amplifier as a kind of "giant killer" that can take the place of all kinds of more expensive stuff (including his 47 Labs GainCard which costs something like $1500 itself, then you have to add at least another $1800 for the official power supply).

Let's think about this... If there are to be giants to kill, then we must believe that there are giants out there. Among the high-fidelity amplifiers, the mythical ideal being "straight wire with gain", are there truly amazing devices in the 2020's that sound "even more high fidelity" than much less expensive amps when paired with typical loudspeakers?

I would argue: No, there are no giants left to slay. Sure, some amps are giants when it comes to size and weight, or have giant-sized MSRPs; however, we're talking about sound quality. Salespeople and the audiophile media would like you to think otherwise since there must be a market out there for the ever-more-expensive "ultra high end" based on sound quality, right?

If we look at the blogger's 47 Labs GainCard (see Stereophile measurements here), we see a less powerful amp performing at around 20W (into 8Ω) before clipping, modest distortion vs. frequency performance with increased distortion at low and upper frequency extremes, and maybe some power-supply related noise in the FFT. The fact that he preferred the AIYIMA A08 PRO is no surprise based on the objective performance since it can deliver more than twice the amount of power with more consistent, low distortion across the audible frequencies.

Sure, one could subjectively use all kinds of claims to justify a preference in the sound quality, for example to quote from the blog:

"This little guy got rhythm and PRAT and is also very musical as well. It also has great soundstaging; despite not being the deepest, it’s wide enough to fill my whole living room! I also hear nuances of musical instruments and details. Vocals are natural, uncanny and realistic, not at all without emotion. Highs are a tad on the dark side, but while they don’t sparkle there's no lack, smooth and soothing (perhaps it's also the signature of the Watt Emerson). Bass is solid, with body and authority, tuneful and with a tactility that is lifelike! Overall picture is very musical. On some music I detect some hardness on the edges, which may or may not be limitations or characteristics of Class D amp; I may want to use some softer cables to pair with it."

That IMO is beautifully written and I wish I could come up with subjective content like that! (Maybe ChatGPT can. :-) But are those descriptions true in the sense of them being reliably replicable perceptions among many audiophiles? Who knows, even though I would agree with the blogger that the AIYIMA does sound very good even if I can't honestly use terms like "PRAT" with a straight face.

I think with the improvements in amplifiers over the years, and the quality we're getting with inexpensive Class D devices these days, we're approaching the point of "perceptually more than good enough" even at the $100 price point for most audio lovers and audiophiles. This is similar to the state of hi-fi DACs where at a low price, the fidelity IMO has easily reached a point of "perceptibly perfect". Sure, we can spend more on features, build quality, etc... but be extra careful when describing uncontrolled, unblinded evaluations of the sound quality!

If there are truly hi-fi amplifier "giants" out there, show us which ones and into what speakers. Let's see if audiophiles can agree on the remarkable sound quality such giants supposedly can provide.

On being CHEAP:

Let's face it guys and gals, much of the content we read and watch online is vacuous stuff. There's definitely a lot of "style over substance" out there. To be honest, that's the sense I get when watching material like this as I was researching opinions on the AIYIMA:

So, if you watched the video, did you learn anything in that presentation from a channel with the tagline "Audio - Video - Tech - Design"?

Let's see... There's side discussion on nearfield listening which is a bit nonsensical when talking about amps that can provide >50W power. There are also inaccuracies here - why is nearfield 75dB any different than 75dB SPL in a room when it comes to being "loud" (around 2:45)? True, manufacturers claiming TPA3255 amps hitting "300W" are selling a fantasy, but these little boxes can easily go beyond some expensive Pass/First Watt amps (like this). Besides, as an audio reviewer, he knows that exaggeration of power specs is everywhere right? If there's anything we've learned from reading manufacturer advertising, it's that we should independently verify the specs regardless of whether it comes from an inexpensive brand or stuff in the "high end". And what has he done to verify for viewers just how much power the amplifiers he reviews can honestly provide?

For example, he claims this video was initially supposed to be a review of the Arylic B50. He talks as if he believes the Arylic is truly a "50W" amp [5:20]; it's actually 30W into 8Ω since it's a TI TPA3116 inside and that 30W is at 10% THD+N. Is it any surprise then that it may not have driven his speakers particularly well and distortion at "100%" volume might not have been good? The Arylic has features like the HDMI input which could be useful, but as an amplifier, it clearly belongs to a tier below the TPA3255 devices like the AIYIMA - was he able to notice the difference and express this basic fact to his viewers? (The TPA3116 is what was in the Yeeco I measured many moons back, in general not the kind of amplifier I would recommend to audiophiles.)

He jumps around in that video between the different amps while making generalizations that I don't think are accurate. Specifically for the AIYIMA A08 PRO, check out his frequency response measurement at 7:14. Hmmm, looks to me like he turned the AIYIMA up a little louder! And if he doesn't like the relatively higher treble in that measurement (is it also possible that the Cambridge is "darker" sounding?), isn't that what the Treble knob is for? What's the problem? And what does it mean that his results are "different" each time he measured the frequency sweep in his room!? There's always a small difference if that's all we're talking about, or maybe there's something wrong with his technique or amp if the results are truly way off each time? Maybe the "quality control" he needs to think about is what he's actually doing to test these things, not necessarily manufacturer issues.

Then there's the part about audible "ringing or whine" from his tweeters (8:15) with these inexpensive amps. He must be talking about a high pitched noise, not "distortion" since this is arising out of silence. Odd, I don't hear any issues on my end with various speakers using the TPA3255 amps. We don't know what source, preamp (gain structure), or speakers he's specifically using to complain of this problem. He apparently has done nothing to diagnose the source of the issue (this noise can be measured, right?). As such, I think the viewer can't know what he's actually talking about.

Notice his version of the wife-hearing-something anecdote with Kristi asking him "Do you hear that?" (8:30), supposedly about distortion heard at just 60+dB SPL as evidence that there's an anomaly. It's similar to the apocryphal anecdote of a wife in the kitchen who can hear all kinds of amazing differences claimed by audiophile magazine writers. He also says Kristi's high pitch hearing doesn't go to 20kHz in auditory testing - does his!? So is this then justification that the sound anomaly is even more significant because someone with less-than-childhood-perfect hearing acuity can hear it? How odd.

By the way, if indeed there is some "ringing" when listening and it's not just persistent noise, one could try a simple EQ to deal with perceived harshness. Something like this gentle high-shelf with low Q to tame excess content mainly from 5kHz up:

44.1 and 48kHz upsampled to 88.2 and 96kHz respectively; give the software a bit more latitude for the EQ processing. Sounds smooth, reduced fatiguability with some of the harsher pop sounds on "bright" speakers. Also can help some of the old "tinny" material from the '80s. "Procedural EQ" option to apply to different speakers in the multichannel system.

Might be especially helpful for those with metal tweeters (eg. aluminum, titanium) that have break-up modes close to 20kHz.

I could go on, but this is just a painful video to watch and listen to from a guy who's supposed to have been reviewing for years (he says 20 years near the end). I guess I'm not completely surprised given his review of the Fluance speakers and presentation on measurements I noted years ago. To me, this is an example of what "style over substance" looks like in the age of the YouTube video monetization cottage industry, much of which is obviously questionable even at a surface level for experienced audiophiles.

Dear readers, it's not that I want everyone to buy "CHEAP" China-made amps or DACs or whatever. I suspect most of us reading here can easily afford a $1000+ amplifier if we really want to. But being "more objective" in examining the properties of these recent inexpensive devices, I'm impressed by how they sound and what they can do regardless of comparisons with other devices - feel free to compare, but objective results can also stand on their own. Small size, low weight, good power level, low distortion, and high efficiency are I think desirable characteristics that satisfy playback needs, not just the low price.

Andrew Robinson and Kristi seem to like the Cambridge AXA25 amplifier which looks like a reasonable unit as well with multiple inputs and a balance knob which is good. Nonetheless it is only rated at 25W into 8Ω, would be less efficient as a Class AB amplifier, is larger, asking twice the price of something like the AIYIMA, and lacks Bluetooth input if that's useful for you. Maybe I'll give it a try at some point... But I have a strong suspicions that the Cambridge's performance is not going to be particularly impressive for distortion and power. I suspect it's much more likely that Robinson's opinions in that video are based on negative biases rather than actual performance characteristics - negative biases related to these amplifiers being "CHEAP" (emphasis his) surely must play into this!

Many YouTube reviews/channels are to me like certain audiophile magazines with nice pictures but at best add little to the discussion, and forgettable. A bit like the superficial glossiness of TAS with paucity of technical details, and no real insights since everything reviewed will have their plusses and minuses spoken in vague subjective testimonies - one device is "fun", another is "articulate", and another is "refined" (have a look at Robinson's B&W 703 S3 review for a taste). Some videos add to misinformation and the viewer ends up more confused afterwards given overgeneralized or just plain incorrect content (IMO, like this video above).

I believe that a good balance between objective and subjective reviewing is still far and away preferable with a meaningful legacy that adds to the audiophile hobby. Despite some missteps, I still think that among mainstream magazines, Stereophile over the years has done a reasonable job at straddling the balance.


The new TIDAL quality tiers: hi-res "MAX", CD-quality "HIGH", lossy 320kbps "LOW". MQA "MASTER" no longer an item.

In other news, it looks like TIDAL is likely flipping on the FLAC hi-res content this month beyond the iOS beta subscribers, superseding the failed MQA. About time they saw the light and inevitable since the bankruptcy. Over time, the old MQA content will get replaced as they clean up the "MQA-CD" 16/44.1 stuff along the way - TIDAL team has confirmed this. Furthermore, it looks like the web player will be able to handle hi-res playback. This is a nice upgrade, perhaps related to the fact that there's no need to decode any proprietary codec.

Hmmm, I wonder when the major audiophile magazines will say something about this!?

MQA went into bankruptcy protection on April 3, and I don't think Stereophile or TAS or Hi-Fi+ have even acknowledged this on their pages over the last 4 months - more than a fiscal quarter! It's not like there has been much other news in the audiophile world recently. Considering they were very quick to praise the company with articles, isn't it kind of weird that they don't even report that the company is essentially defunct and the last significant source of MQA-encoded content is abandoning it? Shouldn't "journalists" tell their readers about these things, especially for those deciding on whether a DAC purchase should include MQA decoding (typically adding to the price)? As usual, we have to wonder how much responsibility the magazines should have in presenting a balanced perspective for their readership. Maybe by the time the mainstream audiophile media finally reports on this, it's basically the bookend to this unfortunate codec drama.

August is here! Time for a little holiday soon. Hope you're all enjoying the music and having a great season...


  1. MQA: the fact that the big time audiophile press doesn't acknowledge the obvious is telling. It's simply the other side of the coin of their sellout for MQA. No intellectual honesty and no sense of responsibility to their readers. Just flogging whatever comes around, trying to get people to spend money.

    1. I agree Danny,
      Interesting to watch it play out like this, which makes it so transparently clear to audiophile hobbyists just what "side" the press is playing on and for whom they prioritize their biases. You would think that at some point they need to "cut the losses" and just get on the side of history that's simply, obviously, playing out after all these years...

      Maybe the strategy is just to weather this out. Let MQA die saying nothing other than the occasional kind words in reviews. Eventually audiophiles and music lovers forget all about this sorry chapter, and it's business as usual. Or maybe it won't work out so well in that they've lost the trust and whatever loyalty left of hobbyists and audiophiles. Readers simply recognizing that their voice, the companies they represent, and this "high end" segment is simply irrelevant to the honest high-fidelity pursuit.

  2. Hej Arch!
    Another most interesting and varied read. I joined the Kickstarter campaign for the Fosi Audio V3 which utilizes the same TPA3255 as the Aiyima. It boasts top-notch components and is a very minimal amp with only a volume control, 2 rca inputs and speaker terminals. It fits comfortably in the palm of your hand. I bought it with the 48v power supply which gives me more than enough juice for my needs. There are loads of favorable reviews from the usual suspects on you tube but I have yet to see it mentioned in the ahem, “serious publications”. I also upgraded the two op-amps to Sparkos SS3602 which did make a difference. However one can question the logic of throwing in 160 dollars in op-amps in a 100 dollar amp 😊 Nonetheless it is extraordinary what is achievable today for so little money. I have the amp in a desktop setup. Dali Menuet SE speakers, an op-amp upgraded Aune X8 Dac connected to my labor of love pc. I cannot complain. Occasionally I will use my Little Dot headphone amp as a preamp. The near field listening experience is highly immersive. This little amp replaced my beloved Luxman L-10 freeing up a lot of desktop space!
    I am not sure if I read the following on your blog but I am reminded of it every time the discussion arises concerning the value or necessity of high-end audio equipment. Especially the part about amplifiers.
    What about the amplifier?
    Vastly exaggerated in importance by the audiophile press and high-end audio dealers. In controlled double-blind listening tests, no one has ever (yes, ever!) heard a difference between two amplifiers with high input impedance, low output impedance, flat response, low distortion, and low noise, when operated at precisely matched levels (±0.1 dB) and not clipped. Of course, the larger your room and the less efficient your speakers, the more watts you need to avoid clipping.”
    Here is the link: https://www.biline.ca/audio_critic/critic1.htm
    Cheers. Take care //Mike

    1. Thanks Mike,
      Nice link to the Peter Aczel article. He was quite the character. ;-)

      That Fosi Audio V3 looks great. No nonsense, simple design to basically achieve the best that you can get from the TPA3255 with op-amp rolling option, cool! I see they measured very well on ASR as well.

      I agree with Amir when he said in that review:
      "State of the art DACs run on highly performant silicon that when well implemented, produces the best performance we have seen. We are seeing similar development with these class D IC amplifiers. Noise and distortion is quite low and beats many amplifiers in the market. They bring two drawbacks: external power supplies and load dependencies. If the latter is resolved, these amplifiers would obsolete large segment of the audio market."

      I hadn't seen that review before and it totally resonates with my impression looking at these TPA3255 amps as well over the last few months.

    2. Also enjoyable: https://www.reddit.com/r/audiophile/comments/dt4xin/peter_aczel_what_i_have_learned_after_six_decades/

  3. Yes, I can afford a $1000 amp. The amp driving my LS 50 Metas is a Purifi Eigentact, but the amp driving my Kef HTC 3010 SE center channel is an Aiyima A07, and there's really not much difference between the two. One cost more than $1200 (or more like $4K if assembled by a high end company like NAD) and is probably considered Edge of the Art by most audiophiles, and the other was purchased for $79 from Amazon.

    Bought it because I wanted to add cheap center channel that used Kef's concentric driver that would fit in the tight space under my LG C1, and I really didn't want to spend another $1000 to drive it when I only paid $150 for the kidney shaped earlier generation Kef Center on Ebay.

    And that center driven by the Aiyima A07 sounds just fine, thank you. I paid l.t. $250 to add a center to my system, and I think it betters any number of systems with super expensive home theater centers I've heard over the years. And I wouldn't hesitate to use the Aiyima on my LS 50 Metas, particularly in the near field, because I'm certain it would do a great job driving them. These days, it's possible to get high end sound with $300 worth of starter electronics if you just follow some of the reviews here and in places like ASR. So why pay more?

    1. Nice one Phoenix,
      Yup... Why pay more? ;-)

      Mindboggling to me the MSRP of stuff. Amps are at least active devices and there's technology inside of them so nothing wrong with paying more for good quality products. I remain particularly amazed by the things that literally do nothing (other than conduct electricity) like cables and stuff like that... I suppose if audiophiles are still willing to spend $$$ on snake oil, there will always be a market for exaggerated claims.

  4. I think some people ignore some simple and obvious facts, that made me personally buy the expensive Benchmark AHB2 instead:
    - speaker protection. I don't trust these little cheap boxes to have any, or at least not a really good working speaker protection. Both for overloading the speakers as well as internal amp error that will destroy the speakers. The AHB2 has all this and it works.
    - SNR unbeaten, no issue in whatever application
    - no external power supply brick
    - no (zero) HF spit out at its outputs
    - reasonable size and weight
    - no hum in itself or with others due to internal, cleverly regulated switching power supply
    This is reference technology that comes with a price, but gets you the best you can get for many many years, plus a reputable manufacturer where you will get service and help. Taking all this into consideration this amp is simply worth it to me.

    1. Hey Tech,
      Yup, absolutely! The AHB2 has been the purchase-and-forget amplifier for simple sonic purity since I think 2016 when it came out. An important "benchmark" in no-nonsese hi-fi.

      Will keep an eye out for one here locally :-).

  5. Hey Arch, just want to thank you for these articles. I recently got an Aiyima A07 for a really good price and using it with a bedroom system. Excellent sound. Nice to see the measurements of these chip amps and the similarities between the models across companies.

    I like how you condense so many thoughts into one article! The complexity you put into even just 1 of these articles puts basically every other audiophile writer to shame. I think it's because you're not afraid to just "call it" as you see it and assume your readers are smarter than the average grade 5 newspaper reader who barely goes beyond the headlines. Bravo!

    Congrats on the work on MQA. As someone who has contacts in the audiophile industry, I know your articles have had a big influence on how many people even in the industry think about MQA. I'm sure it must be gratifying to see this outcome where truth prevailed!

    The "audio press" has been an embarrassment. Wish there are more writers willing to investigate independently instead of just paying lip service to buddies in companies.

    Keep up the great work!

    1. Greetings Stax,
      Thanks for the comment. Hope you're enjoying the little A07; seems like a competent little amp!

      Yeah, I think not having ties in the industry and not doing this as some kind of career goes a long way towards being free to examine and comment on what I see as nonsensical myths and other hype. The whole thing about MQA should have smelled fishy from the start for the experienced writers in the audio press. I suspect being "friends" with someone like Bob Stuart must have clouded judgments and the press was just lead to comment positively. I think there's a need for audio writers to review the nature of their relationship with industry. This is of course not unique to audiophilia. Press should always have the freedom to research and speak truth to the varieties of advertising used on audiophiles.

      Well, I think soon, once all the dust settles as some "grieve" over the loss of MQA, and others "celebrate" that they didn't waste money on the MQA scheme, it'll just fade into the background. That will be good. So long as we as hobbyists learned from this experience, never to repeat a failure to show skepticism for these kinds of flaky companies.

    2. Hi Stax, I applaud the inevitable demise of MQA as it from the start looked suspicious, lacked transparency and above all was so aggressively defended by it"s creators. I do wonder though, why this codec is still included in many new products. Some companies are offering a with or without choice, but why bother? With Tidal subscribers being the only obvious target group comprising roughly 5 million, where do they hope to sell these products? And with tidal soon dumping MQA, where will their clients come from? // Cheers Mike

    3. From what I can tell, it's just inertia in the pipeline. For example ESS designed a few dac chips with MQA filtering licensed in the hardware like the ES9069 they need to sell as "new" products. I don't think most manufacturers were amazed by MQA but willing to put it as a feature in their specs for all their "next gen" model refreshes and some consumers asked about it.

      It was like this with HDCD as I remember also. Hardware continued to support it for awhile but then faded away. For MQA it'll be a lot quicker I think because of few legacy MQA-CDs still floating around now that streaming MQA has stopped which was the lion's share of the content.

      I think magazines are not talking about the death of MQA because there's still hardware inventory to sell and even though knowledgeable audiophiles already know, there might be audiophiles out there still unaware and still be some demand for the stuff.

  6. Hi Arch,
    That is an absolutely enjoying and great post which I thoroughly enjoy reading it!
    To me, the post that I wrote about the Aiyima A08 pro is purely based on my own experience ever since I was a first grader and totally subjective, lol. The A08pro was supposed to be an interesting and quick review of a cheap product and I'm expecting I would switch back to my current amp as soon as I spend enough time with the A08pro. Instead, l have been extremely happy with my current setup that I am reluctant to switch the Aiyima out of the rotation afraid of ruining the balance of the setup. I do constantly researching on more expensive Class D amp for my next upgrade and in fact am eyeing on the Hypex 252 that you are using. Nord has their value line selling at 350gbp seems a good upgrade. But having read your comments, I may have to look for better options!

    I also think Andrew's review and many other reviewers' posts did not do justice on the A08pro and is really disappointing indeed.

    Last but not least, not only did I own the 47 Lab, I have owned a few more power amps with one puts out 300W per ch. But none is able to provide as much fun as with this little gem!

    Whether or not it's a giant killer, we do agree that Aiyima A08 pro is
    a very respectable product able to pump out decent music at dirt cheap price in the hifi world, right? :)

    E Lo
    P. S. Do pair it with a tube preamp for more cerebral performance!

    1. Greetings E Lo,
      Nice seeing you in these parts! And applaud you for writing the blog post and sharing those experiences.

      I agree, the subjective experience with these little Class D chip amps can be startlingly good and worthy of consideration with audiophiles who perhaps previously like yourself would have thought it would have been a quick listen and then switch back to what you had before!

      Glad you're enjoying it and thanks for the tip on the tube preamp. I have an old tube headphone amp and preamp I should give it a try with... Thinking about it now, could make a very interesting small system with both loudspeakers and headphone capabilities.

      Yeah, Andrew Robinson's video is disappointing...

      All the best!

    2. Do keep me posted on your experience with Aiyima and a tube pre!

      Having said that, as the name of the blog created by Doctor John had suggested "cheaptubeaudio", we like to look for bargains across all spectrum of prices! We believe with knowhow, lessons learnt gained over the years, we are wise enough to disregard the shelf talk and form our own judgement on what's best for value!

    3. Fantastic work on the hunt for bargains, E Lo & Dr. John.

      I believe, probably like yourself, that one of the markers of technological progress is not whatever we see in the "High End" these days with stratospheric prices (although admittedly it's fun to listen to and see at audio shows and such). The "spec" I find most interesting are the MSRP numbers in the range that is within reach of the common man/woman coupled with performance that maybe a few years ago would have been found only in devices out of reach.

      I look forward to the day when we see MSRPs of GaN amps well below $1000 with fantastic performance. ;-)

    4. You think GaN is superior than other Class D amps? Have not heard of it yet.

    5. The GaN transistors are capable of switching at higher speeds, more efficiency and are even smaller so for example that 460kHz switching noise we see with the AIYIMA would be even higher out closer to 1MHz.

      Will not automatically ensure better sound but technically can have some benefits... All whether it's done well as with any technology.

      I'm sure we'll talk about this and engage in many audiophile debates when they're more available!

    6. I see.. Peachtree is having this GaN amp and price is notso outrageous. May be sthg worth looking into

  7. Regarding Andrew Robinson and his reviewing.

    My main beef with Robinson is that, although I appreciate the quality of the production, at this point is that I can barely stand to watch his videos. That's because he has fallen to youtuber syndrome. It's not just the goofy face/click bait thumbnails. It's that his act has grown over time such that now he is exaggerating and over-acting in every word he says - the sort of smarmy "a few degrees too chill and smooth" presentation, yet now every damned word emphasized with actorly vocal acrobatics and facial ticks. Apparently the idea is we are so attention deficit we need someone to exaggerate everything they are saying. Ugh.

    But aside from that...

    I actually appreciate his subjective reviews. Generally, he gives a good lay of the land regarding a product, it's technical story, build quality, what it's like using and living with it. And I think he's quite good, especially in speaker reviews, at getting across the character of a loudspeaker, especially contrasting different speakers. When he's talking about a brand I'm familiar with, his descriptions strike me as accurate.

    1. Thanks Vaal,
      Interesting observation about the "YouTuber Syndrome". I was thinking also why I could not tolerate most of the videos as well which is why I only run across them once awhile if I'm testing something and they happen to pop up.

      Production quality is great so it's not that. A purely subjective presentation of something that appears to be accurate is good (as you say, maybe the speaker reviews are fine)... But:

      1. The moment he goes off the rails and clearly says things that are questionable or grossly technically inaccurate really collapses the "professional" production for me. And when this happens plus...

      2. As you alluded to, the vocal and behavioral presentation with those "acrobatics", "tics", dramatics, trying to be personable, looking into the camera like that with the crooked smile really comes across as highly superficial for me. Like a slick salesman who really doesn't know that he has reached his limit of credibility but yet keeps pushing (especially in that amp video). Really painful to watch when this happens.

      I get this same feeling watching scam televangelists or late-night infomercials... Oh well. Maybe his presentation comes across as fine for others.