S.M.S.LA300 HiFi Power Amplifier, Class D Integrated Amp SDB Sound Effects 2.1 Audio System Hi-Res Audio Receiver RCA/Bluetooth 5.0/USB Input 8 Modes of EQ 165W x 2 THD+N 0.004%(with Remote Control)

Just like with the A20a I had recently, I purchased the A300 with the intent to use them as monoblocks. I thought it would be cool to have amps underneath my Lintons on the stands, and admittedly, have gotten caught up in the swirling opinions regarding the benefits of “MORE POWER”. After some disappointments with the A20a, I turned to the A300 which I had just recently discovered. At the $150 sale price, I knew resistance was futile. Are these the cheapest entry into monoblocks? Naturally, I’ll be making comparisons to the A20a throughout this review.Starting with the build and functionality. Now, this is usually something I don’t care to spend too much time on, but this is where the main deciding differences lie between this and the A20a. For one, I think these just look better. Black just blends in effortlessly and they disappear visually much easier than the A20a. The volume knob is awesome! More like an infinitely spinning disc with gentle clicks for feedback. I love that it sits flush with the face of the unit, helping it look more streamlined. The power button is much preferred over the lever of the A20a. Bonus points for not having to hold it either! One click on, one click off. The blue display numbers aren’t too jarring, especially when turned down to 1 brightness, but are more difficult to read than the orange display on the DX3 Pro+. Binding posts look/feel cheap compared to the nicer ones on the A20a, but they function so I don’t really care. Same with the housing, A300 is thin and hollow whereas the A20a feels more substantial and hefty.But again, here we have a mediocre implementation of bluetooth. A feature most of us won’t use but have to pay for. Pass. On the brightside, the included remote is a glorious addition! Being able to power the units on/off remotely is invaluable, as is being able to control the volume if not using a preamp (more on that later). The included digital filters (tone controls) are also a nice bonus, being able to mess around with the sound if one wishes. And I’ll take the digital volume of the A300 over the analog volume of the A20a any day! All said, here we already have a better featured, more versatile package than what was offered with the A20a.On to power. I tested a single A300 in stereo, dual A300s in mono, and my PA3s in stereo. I set my UMIK-1 up at my listening position 6ft away from my Lintons and used REW to produce a 75db test tone in these different configurations. The amps were maxed out on the dials and my DX3 Pro+ was used as volume. The results:(2) A300 in mono: -43 volume(1) A300 in stereo: -37 volume(1) A20a in stereo: -34 volume(1) PA3s in stereo: -22 volumeMuch greater volume and power than the PA3s! But a less significant change going from stereo to mono. Using these as monoblocks, I detected a level of hiss that was consistent from 0 to about 50 on the volume. Onwards past 50 and especially at 55-60 (max volume), the hiss got louder and more distracting. Thus, I settled on using these at 50 when using the DX3 Pro+ as the preamp. However, I soon ended up stacking both A300s front and center, switching the DX3 Pro+ into DAC mode and using the volume normally on the A300s. Close proximity offered the advantage of using the remote to control both at once, although I didn’t always find this consistent and it would change the volume of one and not the other. Sometimes they both magically “rematched” themselves when adjusting volume, but other times, I had to get up and manually adjust one dial to rematch them. I liked this configuration better, knowing all the power was available and I wasn’t cutting a significant portion off at 50/60. The digital volume kept things perfectly consistent, being able to listen at 1/60 and the channels were perfectly matched.So what now? Well for one, these are definitely usable as monoblocks with their unbalanced RCA inputs, the A20a were not (much too noisy in unbalanced mode). Both are still perfectly viable to be used in stereo with a single unit, so don’t sleep on that. As mentioned earlier, the biggest differences between units come cosmetically and in functionality. It really depends on what you value most, but I just don’t see much advantage of the A20a unless you love the look or need balanced inputs. Otherwise, the A300 is an easy pick over the A20a for me. Grab ‘em at $150 and the decision is almost too easy.Finally, the reason I’m sticking with the PA3s lies in the hiss volume that emits from the speakers, or lack thereof! Seriously, the PA3s is so dang quiet and now I have a true appreciation for it. The A300, like the A20a, is definitely audible especially if in a quiet room. Even when I thought I got used to it, I’d hit mute on the remote and was like “ahhh quiet”. Some may never care or even hear it depending on your ambient noise levels and speakers. Personally, since I’d never approach even a fraction of the available volume and my preference for as quiet as possible devices, the PA3s becomes the winner by default. Plus, we all know that splitting a matching equipment “stack” is blasphemy.Oh. I almost forgot. They all sound the same to me.

As an aged audiophile, I've been playing with mid-fi equipment for over 50 years. I've had amps from Rotel, Acdom, Marantz, Analogue Audio and others. Most recently I've been using a Schiit Audio Saga+ preamp with a Sonance power amp and KEF Q350 speakers. The Sonance is a quality amp, if relatively unknown. I was looking to reduce the footprint of my setup while retaining reasonable power. So I decided to try the A300. Swapped it in for the Sonance and started playing. Wow!! Another reviewer said the A300 was smooth, and that's pretty much the case. Smoother at least than the Sonance. I played Hi Res streamed from Qobuz and some CDs. Every part of the range was great. I wasn't hearing bass, mids and treble - I was hearing a cohesive one-piece sound. Not edgy like the Sonance but complete with fine detail and well placed instruments in a beautiful soundstage. Utilizing the built-in high pass filter made integrating a powered sub easy and very effective.I experimented by removing the Saga preamp and plugging my sources directly into the A300. An even more resolving presentation. Even though the Saga is a passive preamp, in comparison to the A300 in direct mode the Saga seemed to add a slightly soft glow to the sound, not at all unpleasant but without the detail and clear top end of the A300. The A300 is quiet and runs cool. The EQ menus are nice to have though I use Direct Mode most of the time. The proprietary SDB mode is akin to a loudness contour and is helpful at lower volumes. The Soft mode can help tame down an overly hot recording. As mentioned the high pass filter is great. I don't object to the blue info screen although SMSL has more attractive screens in lots of its other equipment.So that will be on the short list of things to be improved. The remote is simple and effective but it does need precise line-of-sight to the amp. For my purposes a third RCA input would be valuable but most people should be happy with the two provided. I don't use Bluetooth but I tried it out and it works OK; convenient, but no match for my DAC, CD, or turntable.This is great Amp. Period. Honestly, it sounds superior to any amp I ever used. My KEFs never sounded this good. I had tried an Aiyima A07 amp complete with Sparkos discrete op amp upgrade and while it worked well it always lacked the detail and beautiful top end of the A300. Seems like the Infineon chip in the A300 is as good as reported. The A300 size also helped me clean up my stereo layout.I am very impressed and very happy. My thanks to iiWi and other YouTube reviewers that recommended the SMSL A300.