I have two of these setup as mono blocks. They have had no issues driving a set of Polk legend 200 speakers which do like power. Sounds good to me especially for the low price. The TI chip is surely a very popular one these days.

The AIYIMA classic version A07 and the high-end bridged version A07 MAX ,They are both very good value for money, both in terms of sound quality and appearance, and if you're an prime member, you can even get the prime price

Nice that Aiyima asked you to review that amp I did not know how you would approach your review There are a lot of reviews of that amp but most of them do not really get much into the practical power Comparing it to a tube amplifier based on practical power is useful information

the Aiyima A07 Max sounds nice for a cheap amp when using it as a simple stereo amp, but when two of these units are used as monoblocks they are really impressive budget amps.

Thanks for taking the time to check this little amp out, I use mine for the sundeck and garage, a powered sub really helps. One thing nobody really mentions is how reliable these are, well my A07 has been chugging away for 3 plus years driving some Elac 6.2 's.

Funny thing about this TPA3255 based amp is that it uses a single/non-symmetric DC rail voltage (like tube amps) and has an inductor in it's output signal path which considerably influences distortion and sound quality (like a tube amp, only much smaller/cheaper indictor). Thus, similar to 'tube rolling' people could do 'inductor rolling' if only those were pluggable and not SMD soldered. TI has a white paper somewhere about their tests with different output inductors on the TPA3255. Quite eye opening.

I got a couple of these the 36v is the best way to go...they are fun, they won't replace a good full size amp,,,what I did with mine after playing around with them is I picked up an nice condition Fosgate surround sound processor and I use the Ao7's powering some extra speakers in a surround sound for once in awhile for fun and movies...they are great for adding on small surround sound channels with an old school pro logic processor without messing up your dedicated 2 channel set up....fun stuff for a few bucks

Ive gone through dozens of these chifi amps. The A07 is one of the few thats really decent. It likes tube pres or a dac thats warmer like the Geshelli Labs J2 Btw.. you can daisy chain out the 3.5 aux out. Its full range

The tpa3255 comes alive with a high amprage lithium battery pack. I was able to get 255 watts rms out of one

This is Skunkie ! She's the best. A very nice and honest review. My respect, Stephe

Great from the heart and honest review... Thanks! I feel better now and dont think I am insane.... I bought a $500 48 volt LiFe Po 4 battery (28Kg!!) with a max current of 50 amps instantaneous current delivery to replace the lap top power supplies that came with 4 small chip amps (Fosi TPA 3255 ) each one running in Mono as part of a four way active system.... They sounded good with the switch mode power supplies, but wow.... Sooooo good with the "mother of all batteries" power supply. I still want to replace them with four of your KT 150 mono blocks (once the tubes are available) but hey I am still loving the music with the "cheap as chips" amps!!

Hi, i compare it with my Accuphase E-600 and this 2 little Aiyima A07max with 2x 48V 10A with or without a Tube Pre-amp destroy the Accuphase on 15T $$ Speakers... I love them..😊

Reason why this amp freaks out on analyzer is that its output is symmetrical. Most D class amps are like that. speaker terminals are + and - negative is not ground!!! If you connect analyzer probe - one pin is live and one is ground. So you short one terminal to ground.

Good review. Always enjoy these videos. Very educational.

Amir at Audio Science Review gives this amp a detailed review. Worth looking at his measurements with the 32 and 48 volt supplies.

@Skunkie. Surprisingly, some of these mini units really have some impressive specs and DO hit hi-fi levels. They have very low distortion and SN ratio. One of the better units that is out there are from Fosi, Specifically the v3 and (more so) the Za3. You might want to try those out. I am considering the latter for a new desktop computer system I am putting together. I think it would be hard to compare solid state amps with tube amps as the latter are designed to produce a different (colored) sound. However, when you said that the A07 clearly trumped the Musical Paradise unit, it just had me shaking my head on how those amplifiers are made. In terms of the power output of these small units, they rate it at 10% THD, which is ridiculous. BUT, many companies DO offer a rating at 1% distortion too, which is realistic. With a 36 volt supply, you could expect to see about a 30watt output per channel. Going to a 48 volt 5 amp supply, this just about doubles to about 55watts. Cheap Audio Man as well as Erin's Audio Corner has done some reviews on these units already. While the A07 is a nice unit (I have the A08 pro from Aiyima), the Fosi units, I mentione, (currently) surpass them.

Hey Stephe, I was wondering if you can compare that A07 Max to the older AV receivers in terms of sound quality. I find a lot of old AV receivers and they are even far cheaper than $80 so I don't know if it's still worth buying them instead of the A07 Max. Thank you. Oh btw, thanks for the video. It really opened my eyes...or my ears in fact. ;)

Yeah those lil chip amps like low impedance loads to drive. They're a current source really xx

It's summertime folks, your $90 is better off in your pocket to buy older gear at yard sales. Personally I have bought a 2015 Marantz for $20, but my real prize was a Pioneer SX-34 for $3.

Refreshingly honest. Thank you! In my opinion, a digital NAD (which has DAC and Bluetooth), would be a no brainer.

Thanks for this. I trust your judgement. I would love it if you could review a high-end class D amplifier and compare it to what you normally listen to. For example, Orchard audio makes $4,000 class D amplifiers. Could they possibly compare to a well-designed tube amp?

What more of these amps need is a switchable high pass for the mains when using a sub like the RSL ia2.55.

Great video in that $$$ vs value are key points to consider when evaluating any product. Secondly, for your realistic approach to the review...

A lot of those little inexpensive amps are great for a desktop system or a bedroom. I imagine that if it weren't for cheap Chinese labor we wouldn't even have many of these kind of products.

Steph, you really should build a value for money RH84 SE amp. Use the 10W Edcors, build it for cheap or even get the super budget 5K guitar transformers from Antique Electronic Supply and build it and I bet it'd put the chip amps and Chinese garbage to shame in the 3-4W amp bracket. Seriously, try it. I'd love to see the measurements.

I believe a lot of these cheap class-d amps manufacturers publish output figures at 10% thd into 4 ohms.

I have a couple of these, Aiyma, and Fosi, they are not that bad and they will drive my Maggie LRS+ speakers without breaking a sweat. At least at the levels I normally listen at. One thing I found is that using a Douk Audio $35 line level booster will improve the sound, as I understand these TI chips like a healthy input line level voltage. The 48v power brick helps, but with more efficient speakers, I did not find it mattered, the 32v brick was fine. I found them all pretty punchy, detailed etc. But, they were two dimensional in regards to the sound, and they can get a bit fatiguing in time. A nice warmish DAC helps in this regard. The SMSL SU-1 comes to mind as a good pairing. I think it is pretty cool what they are doing in regards to hifi gear. To add, my buddy has a $1400 Deer Creek, the latest Class D chip, I forget what it is called, go to Deer Creek Audio, they are there, the two channel model in assembled form. My buddy has that Deer Creek amp, and he also bought the Fosi V3, their ZA3 and their TB10D, the Fosi with tone controls, around $80. I own several of these little amps, and internally, they are all pretty much identical. Well, he put his $80 amp up against that Deer Creek, he kicks himself now for purchasing that unit. He stated yesterday that this little Fosi TB10D when put up against the Deer Creek, that there is not $1325 worth of difference in the sound.

Oh wow I can't believe I'm one of the first viewing this video, Skunkie! This one is going to be interesting, I have a feeling (whether that means this little amp is terrible or decent TBD haha). This is Clay btw (we've talked and messaged about your rp-600m crossovers 😁)

Did you try it set to mono output with the analyser? These class d chip amps are great to use with a PC. I have a pair of used Cambridge Audio S30 I got cheap being powered by a Douk Audio ST-01 Pro amp (class d with tubes on the output side). The setup takes up little desktop space and sounds better than a lot of high priced midi systems. If you want to see what state of the art class d sounds like, I recommend Hypex Nilai power amps that use discrete amplifier modules, no chips. Absolutely flat frequency response from 20 to 30,000hz yet none of the top end harshness associated with class d. They have a very detailed, smooth, natural sound that is comparable to high end solid state amps costing 4 times as much.

This is what I’m thinking for my tri amp set up to run my heils and mid, crown for the 15 sub

These amps have $1 op amps in them. The sparkos ss3602 op amp is a big improvement. Makes it sound analog. I'm sure it still wouldn't compete with the tubes but it sounds a lot closer.

Thank you for being honest and real.

I use the class D twenty dollar range chip amps on my tv and computer. they sound excellent. these amps are so good they make tube amps obsolete. sad but the way it goes.

Total novice here entering the hobby....is this a pure power amplifier?Do i need to hook this up to a preamplifier if my dac does not include one.Thanks in advance!

Thank you for not calling it a giant killer like most You Tubers and their click bait tactics.

Im Surprised class d can beat 400 tube amp, dont you feel class d sound dry?

Try monoblocking them and swap out the opsamps - LM4562s are good for me. OPA2604 went too bassy. AD823 were not bad either.

The 300 watt power rating is what the chip manufacturer publishes using a giant 52volt power supply and is a 10%THD rating! These brick supplies will do good enough for a single 1 khz tone power rating. But with multi-tone and noise input they drop off the charts. 1) because there is so much voltage drop in those dinky power cords to the amp under load. Never a good idea to separate the power supply from the amp… unless ps is very noisy, but trade off will be much less capable amp. Hence way the output seems similar to 6 watt tube amp.

Finally ! a real and honest review for these cheapo classD amps 👌

Very interesting conclusions

In the old days, at least we knew what "peak" & "IHF" power ratings meant, but how the power ratings of these current Chinese amps are determined, I have no idea. I think the only possibility is that the CCP has redefined the 1st Law of Thermodynamics to enable them to say that the output power of an amp can be greater than the power input.

Being an electrical engineering and computer science professor and designer and owner of Johnson Audio Group, an audio equipment manufacturer, an audio amplifier output is not measured in SPL which is sound pressure level that loudspeakers produces not amplifiers which produces electrical signals. Hope this helps

Fantastic review and comparison

It makes 50Wrms per channel.

If they could only have the guts to say it is a 7W amp, I would respect them so much more.

Color preamp with class D?

Honey, buy yourself an SMSL AO200mkI, replace the OPA with an OPA 1656, replace the electrolytic capacitors with sounding ones and throw out all your tube amps. ))

Ill buy it from ya for $50 Ha!

D class is big no-no for me

Inductor on the output ay? It's gotta be a class 'D' amp then! Maybe the o/p chip is 'bridged' as well. So the negative speaker terminals won't be the same level on each channel, which may be why your test rig set-up with the Analogue Discovery II went into conniptions! Your ADII probly has common negative i/p's, which kinda shorted the amp outputs. That Nelson Pass (?) amp you reviewed, from memory, had the worst distortion curves I'd ever seen! - Absolute crap! - & yet the soy boy reviewers were having organ spasms over it! A bit like the world medical authorities - whatever they say - the opposite is probably true.

Class D sucks.