S.M.S.L VMV A2 High Resolution Power Amplifier, Class D Power Amp RMS 200W x 2(4Ω), DSD512 Bluetooth UAT LDAC Aptx-HD AAC, XMOS 32bit 768kHz THD+D 0.0008% with Remote Control

I found information about this amp first based on the audiosciencereview coverage, and it seemed like a solid option for a multiple digital class D amp.Overall, it's been really solid as a newcomer to audio setups for running KEF LS50 metas and multiple digital inputs. It works pretty well for plug-n-play from multiple sources, switches immediately between them without any popping, and the Bluetooth works better than most devices honestly! Connection is way quicker than you would expect.The only very minor complaint I have is - it was surprisingly difficult to open the remote to put in a battery. The mechanism was not at all obvious and was stuck for some time until I banged it on something and pried it open a bit with a flat screwdriver. It was fine afterwards, and I do recommend using the remote so you can use the soft power on/power off instead of having to use the switch in the back all the time!

I was really looking forward to purchasing the A2 and fitting it into my system. As a long-term owner of SMSL's AO200, I looked forward to the increase in power, as well as the value-to-cost ratio that SMSL always seems to do well at. The AO200 is limited to 50 watts per channel into 8 ohms, but the A2 gives you 100 watts per channel, plus uses an all-digital solution to convert PCM and other incoming digital signals to PWM, which is fed directly to the amplifiers. An ADC is required to convert all analog signals to digital to pass through the AX5689 PWM controller and then on to the amps.The A2 is a lovely piece of kit. It is roughly twice the size of the AO200, feels solid, has great binding posts for speaker cables, and has Bluetooth built in that is capable of accepting Apt X and LDAC signals. SMSL also claims that the A2 is Hi-Res, accepting and processing up to DSD signals via USB and up to 24/192 via the other digital inputs. More on this later. There is a pair of RCA inputs. Any incoming signal to these inputs is digitized before being passed on to the controller.Set up was extremely easy. A couple of annoying items: The remote doesn't come with a battery. It's a nice remote but is missing the CR 2032 battery required to run it. Fortunately, I had one in a drawer, otherwise, I wouldn't have been able to use the remote. The coaxial input also doubles as a subwoofer out. If you want to hook up a subwoofer, you're going to have to forgo the coaxial input. The menus on the A2 didn't match what they had in the manual supplied with the unit. I had to go to the website and download the manual, and even then it is as basic as any manual you've ever seen. No descriptions of the different settings.I connected the A2 to my Kef R7 towers. I did not connect a subwoofer initially. I used an AptX connection between my Audio Technica AT LP3XBT and the A2 to listen to a handful of albums. So far, so good. The sound was excellent. It seemed like it had more 'air' around the instruments. The vocals were clear and crisp. There was good detail, but not so much that the sound was harsh or grating. Bass seemed lacking, however, which started bothering me. Anything under 80 hz sounded like it was rolled off or missing entirely. I confirmed with a sound meter. What the heck? I have full-range towers, and I've never needed a subwoofer for music listening even with the cheaper and less powerful AO200. I then dug into the A2 menus and found a setting that was labeled Sub Cutoff. The options under this setting were limited to selecting frequencies from 70 Hz to 160 Hz. There is no setting to disable. Out of curiosity, I cycled the cutoff to 160 Hz and listened as the lower parts of the bass spectrum got even quieter. I cycled it back to 70 Hz and bass frequencies improved. My conclusion: I thought the A2 speaker outputs were supposed to be full-range, but I guess that is not the case. Looks like it will only support speaker output down to 70 Hz, and if you want anything lower than that, you'll need a subwoofer.I have Roon installed on my Mac and connected a USB cable to the A2. I fed it a variety of signals up to and including DSD. It played everything I sent to it but with a caveat. No matter what signal you feed the A2 digitally, it always resamples to 44.1 kHz. The Audio Science Review website will confirm that if you do a search. A Hi-Res amp that doesn't sample above 44.1 kHz? I feel like this is also a limiting factor.I also ran some vinyl through a DJ ART phono preamp and into the A2's analog inputs. The A2 converts these signals into digital for processing. Still sounded pretty dang good, but had the same problem as with digital inputs: The lack of full-range output at the speakers necessitating a subwoofer I didn't have, made the experience much less enjoyable.Some might argue that the A2 is a desktop amplifier, and thus should not be expected to run full range into a pair of towers. Maybe so, but what desktop amp out there is capable of 200 watts per channel into 4-ohm speakers? And the A2 had no issues running my Kef R7s to insane volume, although limited by the 70 Hz sub cutoff, which would free up some power.The A2 gets warm. Really warm. Even just sitting powered on with nothing running through it, it gets really warm.Ultimately, the A2 is being returned. The lack of ability to run full-range without a sub, the resampling of Hi-res signals, a lack of a decent manual, and the heat this thing puts off don't justify the lofty price tag.

Quick shipping, small footprint, more than enough power for 2 SVS Ultra Towers. Happy customer.