I think it is a great little project to see how little you could spend and still clear the bar where HiFi starts. That means, we would take it from a McDonald's burger to a Five Guys burger. We are not going to get at the level of a good steak house. At least that is how I see it. Lets see what a boutique op-amp can do. Mind you, this upgrade path brings you in the territory of a Cambridge Audio amp, and that looks like a real audio component.

Would be interesting to pair this with your preamp

You've got a knack for this! Please do more reviews. :)

Another very objective, honest and expertly supported review. That's why I love your reviews and your channel, instead of these fancy "sponsored" ones. I would really appreciate if you could take a look at the Topping pre90 preamp I recently bought and it sounds better to me than 10 times the price, thrilled (except for the remote)...really appreciate your work. .Keep teaching us..thanks

Been a tube amp user for decades myself (currently a Transcendent Sound T8-LN OTL) but I still really like this thinking about affordable Class D units for DIY! PLUS, less expert DIYers can't kill themselves working on these lower voltage amp - as long as they STAY OUT of the power bricks...

I very much enjoyed your review of the R8, saved me buying one out of excitement over all the positive reviews that never opened up the case (yes I subbed). In this case you are doing good work for people who need sound for a small investment. With regard to decent audio under $500, I suggest used. I have two Audiolab 8000A (integrated 60watt English built) amps that cost about $350 each, I liked the first so much I bought a spare. I'd be pleased to see, amongst your other work, an occasional "blast from the past" review of a commendable older amp with your usual tech insights.

It was interesting hearing your views on one of these a cheaper Class D jobs, which I've never heard any example of, & interested because I've seen some of your valve designs (we call em valves over this pond's-side) I've long preferred valve amps but at 16'ish yrs'old, circa 1977, it was purely for their cheapness, U.K. made vintage pre & power amp combos were cheap & plentiful as I guess folks had long ago or just upgraded to sol'/state & wanted rid of these hot running things, I'd see them in local s/h Mag' sections, shop-window private ads etc . I had vintage Radford STA 25 (2xEL 34 / a ch', Similar Leak TL(?)25 mono's, Quad II's, a little Rogers ECL86 power amp & all sounded Gr8, in memory but they beat the mid '60's s/h solid/state amps easily I thought, & they sold for £10 or £20 back then, I'd earn £20/week in my apprenticeship so they "cost me still". I even kept some running for many years with superior later pre's &/or phono-stages. Now I'm all valves except for a class A solid/state power-amp. Years & esp' eBay saw a pair of ave' con' Leak mono power'amps for £1000 & ++, even the lil' Rogers ECL86 lone-four valved power amp (with sol'/state rectifier) I had fetches £250 to £300, I threw mine away because I couldn't be bothered to buy & fit new electrolytics for the (120'htz?) humming) power amp for the £10 it may have got back then. The vintage pre's are not so sought after, noisy on phono tho the Quad 22 phono sounded good until I put a P.S. Audio pre in its place, s/h of course. Those days & vintage gear are long gone, I guess, Hi-fi shops with s/h sections ...all but gone(?) here in u.k. Companies like Bose (for a.g. sorry Bose) & their marketing never helped old geezers like me who still love music more than ever, I suppose. I've near or actually consistently heard relatively greater things said in reviews about the "Gallium Nitride"(GaN) based transistor class D amps verse the usual silicon Class D's & Class A/AB's Tho they commanded much higher prices whenever I saw them, always favourably reviewed Tho I have also heard what later turned out to be, I thought at the time, utter garbage on certain 'rave review' products (like Naim Nac 32 / Snaps p.suplly, best under £1000 particularly for it's phono stage, I bought a s/h one & it truly sucked, easily beaten by a modular P.S. Audio phono at well under half the Naim 32's r.r.p. price. I've no moral story for it tho except trust one's own ears.

I have an Aiyima A08pro as an interim product but it had then anchored firmly into my system. A07max, with high anticiopation, did not do the magic for me, exactly like you have nailed it, sucked the life of music . Based on this review and the next one with Sparko opamp, I am very curious if this could be another upgrade to my older A08pro! Thanks

Thanks for the review! Especially the comparison to budget-fi tube amps like the Reissong A12 were interesting to hear. In the sub-500 dollar range I'd throw in the Hypex NC122MP (2x125W peak power) module which you can get on asian online stores in an enclosure either with XLR or RCA inputs (just as a power amp i.e. no volume knob) for less than $500. I have those modules in my active speakers and to my ears they are superior to any of the 100...200 dollar amps available elsewhere. Very dynamic, excellent bass control, super low noise and distortion, neutral sound signature, not sharp or digitally sounding. Also available with twice the power as NC252MP but then also a bit above $500.

As always, very interesting stuff.

Good review Stephe. These are not for me but others may see a place for them

First one here❤ interesting stuff this very affordable off the shelf DIY upgrade it’s not for me personally fortunately, I could go out and buy premium stuff already, which I already have all the latest Macintosh components my question is what do you think about McIntosh? I know I am a fanboy of it. Just want to hear your opinion which I value thank you so much Steve Costello.❤❤

Looking forward to your take on the op amps. I ordered two Sparkos op amps for the Fosi Audio ZA3 and I'm confused now whether I should have ordered a third one for the XLR inputs, or whether the two main op amps are doing the job.

It use's a TPA3255 chip set.have built an amp using this chip set,it puts out 95 watts RMS into 8 ohms.For the price it is reasonable.

There are some more expensive Tpa3255 with a built linear power supply. Any advantage over smps? The magic comes in when you add a tube preamp.

will be interesting to see what happens, i like the idea of having one of these amps so i don't have to use a big yamaha amp as my desktop amp haha

The only thing that continues to bug me about this new era of chi-fi...they keep making odd chassis sizes and shapes. It's a cool little unit, but my rack is no place for electric pencil sharpeners. I wish they would just use 1u chassis either half width or full and put the damn power supply inside of it. No more of this making the product cheaper by offering it with smaller power bricks that can't fully power the amplifier in order to have a cheaper price version, either. It's so strange. Icepower has no problem building single board solutions with correct power supplies on the same board. If that was a 1u half width box with the power supply inside of it, I might consider owning one.

Hi, I am thinking of getting this amp and was wondering if the turn on and off pop is loud. I have klipsch bookshelf speakers. My current Breeze Hi Fi is very soft barely noticeable with ear next tweeter.

I only ask you for one measurement to confirm or not my suspicions: the phase curve. At least how many degrees it deviates at 20 kHz. It is the usual problem with cheap class D.

Idea maybe changing the caps in the a70 to some higher end caps too. It can really change a tube amps sound but I'm not so sure how much it will effect the class d amp

Measurements???

A 200W power brick? BS! That thing would explode in flames trying to supply THAT much power! There's not even a cooling fan on it! What a complete joke Stephe! - Or have I missed something? How many watts per channel is it rated at?

daniboun at ASR Chipset: TPA3255+NE5532 Replaceable operational amplifier chips: RT3609SM, OPA2604, OPA2134, LM4562, JRC5532, OP275GSZ, OPA1612, MUSES01/02/03, etc. Distortion:0.0015%(@1W) Signal-to-noise ratio:≥≥116 dB Frequency response: 20Hz-20KHz (±1DB) XLR input sensitivity: 3.8Vrms (19dB) RCA input sensitivity: 1.9Vrms (25 DB)/1.1Vrms (28.5 DB) Speaker impedance: 4-8Ω Stereo maximum output power: 2x300 W (@4Ω) 48V10A Input mode: RCA+XLR Trigger: 12v Tigger input I also see in pictures some Nichicon alu. caps PW serie 2200UF / 63V + SMD RVT NoName 25V/220UF Output caps