AIYIMA A07 MAX 2 Channel Stereo Amplifier Home Audio 300W*2 TPA3255 Class D Power Amp/Bridgeable Mono Amplifier 600 Watt with 3.5mm Line Output for Passive Bookshelf Speakers+DC36V 6A Power Adapter

I purchased a pair of the Aiyima A07 Max amplifiers for use with a WiiM Ultra control preamplifier. The A07 Max amplifiers performed well with the WiiM Ultra control preamplifier using the line out from the WiiM Ultra. I compared this combination with the WiiM Amp Pro. The WiiM Amp, WiiM Amp Pro support digital optical input, that is how I prefer to listen to music via the WiiM Ultra to the WiiM Amp Pro versus the line out/line in (RCA) connection. The Aiyima A07 Max does not provide an optical input, only one pair of L/R RCA connections.The Aiyima A07 Max can be set to stereo mode or mono mode. You can start out with a single A07 Max amplifier set for stereo mode. You later can add a second A07 Max amplifier, set both A07 Max amplifiers for mono mode in a two channel system.Mono mode can provide increased channel separation. Using two amplifiers in mono mode unburdens a single power supply from having to supply power to both channels while maximizing dynamic headroom. As excerpted from the A07 Max owner's manual maximum rated power with the included 36V/6A power supply (in stereo mode) is: 107 Watts x 2 channels @ 4ohms, 100Wx2@6ohms, 94Wx2@8ohms. (In mono mode) the maximum power rises to 190 Watts x 1 channel @ 4 ohms, 150Wx1@6ohms, [email protected] A07 Max amplifier has no tone controls. I prefer to use the WiiM Home app's equalizer functions (both graphic and parametric equalizers are included) rather than conventional bass and treble tone controls. The volume knob on the front of the A07 Max is also the power switch. There are two blue LEDs on the front of the A07 Max. One LED is on the left and the other LED is on the right side of the volume control. These LEDs indicate whether the amplifier is set for stereo mode or mono mode. There is a recessed Stereo/Mono mode switch on the bottom of the A07 Max. Among the small, inexpensive Class D amplifiers the Aiyima A07 Max is noteworthy for being able to be switched between stereo mode (BTL) and mono mode (PBTL).I found the A07 Max sounded better when set to mono mode, including bass extension and tightness of the bass notes. In mono mode, in addition to having to connect one pair of speaker wires to the binding posts labeled "+ Mono Mode -" you need to connect one channel of a typical dual RCA cable to the A07 Max's RCA white colored connector that is labeled "L". If you accidently connect the RCA cable connector to the red RCA connector that is labeled "R" you won't get any audio output from the A07 Max amplifier.Compared to some other small amplifiers, the speaker binding posts on the A07 Max are a bit larger (but still made of plastic and metal, not all metal) and are staggered with the lower connectors shifted slightly to the right for easier access. I recommend using banana plugs to connect the speaker wires. I use the Sewell deadbolt banana plugs (sold on Amazon.)There is a 3.5mm Aux Out connection next to the RCA connectors that is a pass through from the RCA inputs terminals The Aux Out level is not controlled by the volume control on the A07 Max. For connecting to a powered subwoofer I use the WiiM Ultra's single RCA subwoofer output connection.A key differentiator between a two channel audio system based around the WiiM Ultra with a one or a pair of Class D amplifiers (such as the A07 Max) versus using just the WiiM Amp or WiiM Amp Pro is that there is no upgrade path with the WiiM Amp/WiiM Amp Pro that does not involve replacing the WiiM amplifier unit with another amplifier unit. [Update: WiiM has introduced the WiiM Vibelink Amp as the matching amplifier for the WiiM Ultra. You could start out with or upgrade to the WiiM Vibelink Amp from the WiiM Amp/WiiM Amp Pro for ~3db more headroom and maximum power (100WX2@8ohms/200WX2@4ohms) when using the optical connection.] From a cost/value perspective a single Aiyima A07 Max amplifier (or a pair of A07 Max amplifiers used in Mono mode) are a viable alternative to one of the WiiM amplifiers. The maximum available power from the WiiM Ultra/A07 Max combination can be increased by adding a second A07 Max unit (while retaining the original A07 Max), in mono mode. You can maximize available amplifier power of the A07 Max by upgrading the power supply.Should you require maximum power from the A07 Max amplifier you can substitute a 48V/10A power supply for the standard 36V/6A power supply. In dual mono mode, a pair of A07 Max amplifiers set to mono mode and a pair of Aiyima brand GaN 48V/10A power supply units (sold on Amazon), each A07 Max amplifier unit can then provide (315Wx1@4ohms, 240Wx1@6ohms, 190Wx1@8ohms). This is significantly more power, (3dB or more headroom and available power @ 4 and 6 ohms) than the advertised maximum rated power of the WiiM Amp or WiiM Amp Pro (60Wx2@8ohms, 120Wx2@4ohms).I measured the temperature of the case of the A07 Max amplifier when using the stock 36V/6A power supply while powered on, while in use. The case temperature was 82F in standby. In comparison the temperature of the case of the WiiM Amp: 76F, WiiM Amp Pro: 79F, WiiM Ultra: 76F, WiiM Mini: 79F. In comparison the temperature of the case of the Fosi Audio TB10D amplifier with the stock 32V/5A power supply measured 72F. The cooler the better, for longevity. [Update: I measured the standby power consumption of the A07 Max amplifier. Plugged in, switched off, the power consumption measured 0.1 Watt. Powered on, no input signal, the power consumption measured 4.3 Watts. This measurement was for one A07 Max amplifier in either stereo mode or mono mode. A pair of A07 Max amplifiers switched on, with no signal, consume 8.6 Watts.]

I never thought I'd be writing about this, but some of these newly released class D amps (that allow for Op-Amp interchangeability), are now approaching audiophile level, class-AB amp sound reproduction.I've been giving many of these Asian-made class-D amps a try over the past few years. With the likes of the Aiyima A07 (the original), the A07 Pro, and now the A07 Max - along with the Fosi Audio BT20A Pro, V3, and most recently, the ZA3 - audio performance quality levels have risen dramatically among compact budget amplifiers - at a pace much faster than I could have previously anticipated.Before I get into the meat of the matter (for those of you interested in this comparison), in my opinion, the A07 Max begins life out of the box with a slightly overall warmer audio tonality to my ears than Fosi's recent ZA3 release. I find that with or without Op-Amp upgrades, the A07 Max has that slightly warmer sound signature (which tends to inch a bit closer to that much desired class AB tonality). As an aside, even the Fosi V3 has a slightly warmer overall sound signature as compared to the ZA3. I found that the A07 Max's sound-staging is pushed more to the rear (behind the speakers), whereas the ZA3's sound-staging is brought much closer to the listener and extends beyond the periphery of the speakers if it's a great recording (at least on my system).A tidbit of note is that with the A07 Max, one can use a variety of different speakers without noticing much of a tonal personality change. However, what I surprisingly discovered was that the Fosi ZA3's tonal personality changed, dependent on the speakers being used. For example, with the KEF Q150's and Q350 bookshelf models, the ZA3 sounded absolutely superb and and I could listen for hours on end! Yet with others - i.e. my Wharfedale, Mission, and Polk bookshelf speakers that I also have on hand - the ZA3 had a tad more of a coolish sound quality to it. The key to remember here is not to use speakers with the ZA3 that have pronounced treble capabilities (or are considered overly bright). With the A07 Max, that is not much of an issue from what I could discern.As to personal preferences for design appearance, I find that the A07 Max's design does not (subjective I know) look as appealing as the Fosi variants. I don't particularly care for the light gray (silver?) front panel which has a tinny and cheap feel to it - but that is just my interpretation because sonically, it far surpasses what one might think about its looks.In my opinion, the A07 Max punches far above it's price-point. This has brought me to say something that I never envisioned saying - and that is, between the Aiyima A07 Max and the Fosi Audio ZA3, they both are now what I would consider to be my standard desktop reference integrated amplifiers. In fact, they have supplanted my Cambridge Audio AXA25 and AXA35 integrated amps as my main reference units. With the Cambridge amplifiers, their size alone are some 8-10 times the size of the Aiyima A07 Max or the Fosi Audio ZA3. I've placed the Cambridge amps back in their respective boxes and will be selling them soon. I guess you could say that's high praise enough.The A07 Max music is a tad less "airy" than the Fosi V3 or ZA3 (where the latest Fosi amps tend to shine), however, its bass capabilities are about on par with the ZA3. However, in some cases, the A07 Max can project a bit too much bass. Highs such as can be found with stringed instruments in a full symphony orchestra, come through with a silky sheen in good recordings. I virtually get lost in the music from good quality recordings - those performances being characterized as highly immersive and musical. Every once in awhile, I have to remind myself that I'm listening to this diminutive box of an amp. More so, I can listen for hours to the A07 Max without experiencing listening fatigue - and yes, the same holds true for the Foxi Audio ZA3.Now here's the one variable to remember - and you have to determine if it's worth it to you to upgrade. I tend to change out the Op-Amps in most of the class D amps that have that feature. I changed out the 2 Op-Amps in the A07 Max, removing their generic cheap NE5532 versions (often used as the stock Op-Amp in most class D amps), with the more expensive discrete Sparkos Labs SS3602 versions. I've also used (and tested) the MUSES02 IC-based Op-Amps - and all sounded absolutely superb, and my comments in this review are based on my trying and using all of these Op-Amps. The upgraded Op-Amps elevated the audio qualities on the A07 Max quite noticeably - read "expanded sound-staging, smoother transients, warmer sound, increased depth and dynamics." More so, in my opinion, changing out the Op Amps to versions from either Sparkos Labs, Burson, or MUSES, brought the A07 Max more in tune with what a class AB amp would sound like.So do I recommend the A07 Max? A big time "hell-yes," I do - with a full 5 stars! Times are a changin' as they say. No longer does one have to spend $500 - $1000+ or so to get a decent audiophile level of amplifier. The likes of Aiyima and Fosi Audio (and a few other brands) are turning heads for less than $100 USD, and that's a good thing - actually, more so, that's a remarkable achievement! If there is one area that I would change, it would be with the appearance of the A07 Max. The Fosi units - in particular the V3 and ZA3, have a more refined (and higher quality) look to them, whereas the A07 max - for some odd reason - still feels a bit cheaper in both appearance and touch (particularly the front panel area). Of course, this is subjective on my part. I would also hope that Aiyima adds balanced inputs in one or more of their future releases if they want to remain competitive, and I bet they will in their next release of this particular style of amp.It is obvious that Fosi Audio and Aiyima are in competition with each other, trying to play leap-frog with their similar releases. It would be nice to now see Nobsound/Douk (really the same company) do the same thing. Choices are nice to have - but in the end, it is the sonic performance of a given amp that will determine a winner.Equipment-wise, I listened to this amp through the likes of the KEF Q150/Q350 bookshelf speakers, along with the Wharfedale D320 and Mission LX2 models. DAC's used were the iFi ZenDac V2, various Schiit DAC's and Head amps, Topping D10S, and the JDS Labs Atom DAC X. Cables used included Audio Quest interconnects, along with 10 gauge banana terminated speaker cable from Blue Jeans Cables. All music came through with a pleasant sense of musicality, great definition, and separation of instruments (and delineating the sound-stage properly).In the end, your mileage may vary of course, and who would I be to argue.