SMSL AD18 80W2 Bluetooth 4.2 HIFI USB DSP Digital Decoding Power Amplifier

At just over 100 potatoes keep your expectations realistic, do so and you won't go far wrong. I am trying to minimise stuff in the house but didn't really want to get rid of a pair of nearly new Q-Acoustic 2020i's. So I put them on my desk and ordered this.It is dimunitive; fitting very discreetly next to the mac on the desk (see picture) - the power brick, is, however large so you need to think about where to tuck this...however a big power supply is reassuring for HIFI' ists.I read online the output can be digital or tinny...maybe its the speakers or inputs people are using: There are many inputs I am using the USB output of the iMac and playing from my QOBUZ subscription at 96kHz sampling - It sounds fantastic at desk volume listening levels, lovely separation and clarity, bass is present but not too muddy.You can stick anything up it, 3.5mm, USB, optical or connect your phone by bluetooth 4.2. It has a headphone amp too...drives my Sennheiser 598s nicely. The built in equaliser has some good settings for either increasing bass or pushing vocals.Good one

I'm using this coupled with a pair of Denon bookshelf speakers and a Yahama subwoofer. It sounds pretty good for a tiny, cheap amplifier. Compared to the full-size Denon amp I was using until now, the bass is a bit weak from ordinary speakers, and it really needs the subwoofer to fill out the low frequencies. In addition, the middle frequencies sound a bit harsh to my ears but, again, that's in comparison to my previous amp.The USB input appears as a USB soundcard, and does need any specific drivers on my computer. The Bluetooth connected to my Sony phone without difficulties, and was recognized as an AptX device.The unit is smaller than it looks in photos -- about the size of a house-brick cut in half lengthways. It needs an external power adapter, which is about the same size. I was irritated to find it was supplied with a European plug, not a UK one. This isn't a deal-breaker, but it means adding a couple of quid for an adapter or a replacement plug to the cost. It is supplied with a short USB cable which is, oddly, white. There is an external Bluetooth antenna -- presumably because the all-metal casing would prevent an internal antenna working.Geeky technical note -- this unit uses class D amplification. This means that the amplitude of the output signal is controlled by pulse-width modulating (PWM) a current which is either fully on or fully off. Thus negligible power is dissipated in the final output stage which, presumably, is why the unit can be so small. It also means that no separate DAC is needed for digital input signals -- the digital sample values are converted directly to PWM duty cycles. It also means that the analog input has to be converted to digital. There is therefore no conceivable benefit to using this unit with an external DAC feeding the analog input, as is the case for many traditional class-B amplifier designs.Class D amplifiers do tend to have a characteristically "digital" sound -- bright and a little harsh. However, the signal-to-noise ratio is impressive, because there is no analog processing whatsoever.All in all, a good purchase, if you need a very compact amp with direct digital inputs and a subwoofer output.

If you're looking to just power a pair of basic speakers in your setup and don't have much space, this may well be for you. The SMSL AD18 doesn't take up much space at all and it has a versitile set of inputs, digital and analogue. The build quality feels strong and the display is clear. However, if you want to have decent quality output to enjoy your music etc. then look elsewhere.I bought this based on reviews here and elsewhere saying the sound is good and that the built quality is good. On receipt of the amp I got it all setup with a digital connection from my PC into a pair of Q Acoustic 3020 speakers. The menu is easy to navigate and I had reasonable quality sound coming out straight away. For it's small size, it can certainly pack a punch! Volume however was not the issue, despite adjusting the EQ settings, bass and treble settings on the amp and on the PC I could not get satisfactory sound quality. It was tinny in at the treble end, and overall lacking depth in the low to mid range. Everything felt very 'flat'. I may be overly fussy as this seems adequate for a lot of people, but if you're expecting a high quality output from this unit, you will be disappointed.The build quality on the whole is quite good, but the main control you use for everything feels like it is always about to break. It's not loose, but it moves around on it's hub in an unnerving sort of way, not what you'd expect from a product that costs over £100.I spent 5 days with this amp trying to get better sound but to no avail. I returned it to Amazon and have replaced it with an Onkyo 9010 for only about £40 more. You can't really compare the two as they are so totally different, but the Onkyo is a full size amp and does a superb job, the only drawback being it doesn't have a digital input.In summary, if this amp were £30-£50, I don't think I would have been as disappointed, but for over £100 I expected more.