HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

scotty38 wrote: ↑Wed Nov 13, 2019 8:19 pm

slinger wrote: ↑Wed Nov 13, 2019 6:05 pm
I saw them on eBay, but I saved almost twenty quid by ordering from China. The burning question is though, are they any good?

Ha not sure to be honest, I bought one to power my project pre s2 dac but haven’t used anything else with it. It works just fine I can say that. I did take the lid off and disconnect the fan to eliminate its noise, never even gets warm for me here....

It's useful to know about the fan. I was considering either disconnecting it or replacing it if it was as noisy as one of the purchasers said in his review.

I spent several years as a teenager in (then-Colonial) Hong Kong - my father had been posted there and the cultural shock from the grim Pennine wastelands of Todmorden could not have been greater. One thing that this time did leave me with was an appreciation of the Chinese mindset: 'work hard, make money.'.
With the handover of HK to mainland China, the ex-colony had a foundation of western-orientated manufacturing upon which the new mega-city of Shenzhen built and became a massive assembly plant for the rest of the world.

Chinese hifi began as cheap knock-offs with cut-price components in flimsy casings. Then many (UK) audio companies began to get their products made there, this brought a wealth of information about the quality and style that Western hifi-consumers required and the Chinese market adapted itself and began to aim for similar quality within the quantity.

In a relatively short space of time, many ChiFi audio companies have begun to make distinctive and attractive hifi for attainable prices, look at: SMSL, Loxije, Sabaj, Denafrips to name but a few. These companies have seen that by using good components, careful designs, solid cases and high-volume production techniques, there is a market of music-fans around the globe who will be interested.

Another player in the field is Aiyima, specialised in quirky amps and DACs - if you want a tube-amp with a big VU meter then check em out! They appear to have been going for a while and have an in-house development and improvement programme. When I started dipping my toes in the murky waters of ChiFi, one little power amp was gathering much praise for its sound quality, the Aiyima A07, a basic stereo amplifer based around the Class D Texas Instruments TPA3255 chip.



Despite its clunky appearance and basic functionality it had many fans and Aiyima decided to bring out a PRO version with tone controls and Bluetooth - this was also well-received and helped the company's growing reputation. Attractive prices too - the A07 PRO with power supply sells for about 100 dollars in the USA.



These amps are little powerhouses as well, with a 48V/12A power supply the TPA3255 is capable of churning out a massive 300W/ch and then with an audiophile-friendly character that has removed the glare and graininess previously associated with Class D designs.

Idly surfing, I came across yet another, newer version of the A07, the A07 MAX, a complete new redesign based around the trusted TPA3255 and now with stereo/mono switchability. That set off the 'Red Alert' lights in my head! Experience with the Sabaj A10a 2022 showed me that stereo Class D amps are full of fun; bouncy and forward. But bridge them into monoblock mode and you get a beast that has unlimited power, pinpoint imaging and razor-sharp detail. Carefully matched in a system to rein-in the forward edginess, these amps have been providing me with enormous pleasure over the last year. And maybe it is my 60+ ears needing a bit more pronounced treble, or that I listen to recordings in a different way - wanting that extra detail and precision, certainly the sound of Class D is beginning to take my preference.

So, enter the Aiyima A07 MAX:



Very chic with a minimum of clutter. The volume knob doubles as the on/off switch and mono-stereo mode is selected via a little slider underneath. Reviews are glowing with an elegant and musical sound that should please and impress. The amp is available with a selection of power supplies and I have gone for the intermediate 36V option (who the hell needs 600W per channel?) and ordering directly from Aiyima not only gave me the best price, but an extra 5% discount, so a pair of A07 MAX costs €170, quite a bit less than an AQ Carbon 75cm USB lead, for example.

A pair of these will be appearing on my doorstep sometime soon and I still have a pocket-money SMSL DAC to review.

Life's hard ...

So what's the best way to tame the top end (if required) of this type of amp Fret ? With the source or speakers ?

These are Chinese knockoffs of the EAR 834p

https://www.ebay.co.uk/itm/282312879159 ... media=COPY

They can probably be found cheaper on AliExpress.

They are not properly grounded, and are actually dangerous as delivered. They also have quite cheap caps. But everything else is an exact clone of my EAR phono stage.

A bit of light fettling by someone who knows what they’re doing, proper grounding, and a
Recap, and they sound identical to the EAR. I have a modded one as a backup (and my Schitt Mani 2 as a backup to the backup).

Superb at MM, crap at MC. I modded my one for MM only, removing unnecessary MC bits/inputs etc. also modded for variable loading for different carts.

I modded (ok, my tech guy modded) both the EAR and the clone and removed the power supply for each, and housed it in a separate box away from phono stage itself. This makes a big difference. Inky silent blackness between tracks.

I might sell the EAR, as there is nothing between them. I’d still get good money for the EAR, but no so much the knockoff. Would loose too much on that. Regardless, a fun experiment

karatestu wrote: ↑Thu Jan 04, 2024 9:02 am So what's the best way to tame the top end (if required) of this type of amp Fret ? With the source or speakers ?

Mainly speakers. Shrill/bright speakers are not good with class D.

Many DACs these days have PCM filters that control treble roll-off.

And there are always tone controls, equalisers and DSP processing.

My tips: leave Class D amps on 24/7 and give them a week to settle in.

They aren't for everyone but can be serious music -makers.

Finally found the strength to mess about with hifi and top of the list are the new Aiyima amplifiers.



Opening the neat packaging reveals the amps, and they are tiny! About half the size I expected, even smaller than a CD jewel case. Solid though and oozing class. The PSU's are fairly chunky as well.

Inserting them in the Downstairs setup involved a couple of tribulations with a loose speaker plug, sorted that out and fired everything up.

The A07 MAX has a 'Mono/Stereo' micro-switch on the underside and you need to check the instructions for correct speaker/RCA connections. Initially turning the volume pots to maximum, I adjusted master volume via the NVA preamp.

Immediately you get that 'Class D effect' with a forward, detailed character and deep, articulate and incisive bass. Also the mono amps allow me to (finally) adjust the balance of this system.

First listen; cold out of the box and no burn-in, a surprisingly rich, full sound. No excessive glare or edginess. However it's a bit dry and flat - but this should fill out after a week or so - and the amps are struggling to resolve complex passages. Something to keep an eye on.

The up-front presentation is what I have come to appreciate from Class D and these do not disappoint. They don't sound tiny either, this is a big, wide-screen soundstage of authority and control.

So far the ultra-budget Aiyima's are looking hopeful. Now for some serious running -in and then see what happens.

To be continued...

Re-reading my thoughts on the Sabaj A10a 2022 Class D monoblocks, I see that my initial impression was very similar to what I'm hearing from the A07 MAX.

viewtopic.php?f=3&t=51525

Did I mention that drums sound incredible through these amps!

I do look forward to your reviews- thanks

Sounds like these may be a great option for my cycling pain cave

TheRealAleman wrote: ↑Sun Jan 14, 2024 5:03 pm Sounds like these may be a great option for my cycling pain cave

These sort of amps are perfect for starter/second/party systems and if you need more power or quality then get a second unit and monoblock them.