Review: SMSL AD18 – Tiny Wonder

Sound performance

 

Headphone output

For the sake of this review I prepared a bunch of headphones and earphones, ranging from the cheap Letv iem to the marvelous Unique Melody Maestro.
With really sensitive IEMs you can hear a little bit of hiss, mostly due to the USB connexion since I don’t hear it when I use the SPDIF inputs. With 90% of the headphones available, you will never hear it. Only two IEMs were sensible at this point, for the others the background was perfectly noiseless.

The sound is really linear, there is no peak or boosted frequency, so the first listen can seem really dull. It’s not as precise as an RME amplifier, engineered for real audio workstation, but you can hear a lot of details easily. It does not sound as a Chinese amp, in a good way. The closest thing I heard would be the O2 amp from JDSLabs, with a tighter bass and a bit more distortion. The sound stage is wide, thanks to great left and right separation, even if a balanced output would have been a nice addition. Imaging is good too, with my old 1964 V6S I can precisely say where the singer was positioned on live music recordings.

There is plenty of power for IEMs, less so for big cans, even if the amp retains an excellent dynamic range from 2 to 36. Yes, that’s a strange number. From 0 to 1 you won’t hear anything at all, I don’t know if it’s a bug or if it was really design like this. Past 12, with IEMs, you can get seriously deaf, leaving you 10 steps of usable volume. Some might need more, I don’t.
Plug in the Sennheiser HD800S and you can clearly feel the limitation of this amp, where the JDS Labs Element can push this headphone to its limit, the AD18 can just make it loud. The good news ? You never get any distortion.

After a few weeks of listening, it became obvious the linearity of the SMSL AD18 was its biggest strength and weakness. Like an old Burson, you can virtually throw anything at it and it will never fail neither will it shine. It lacks the little something which make you listen to your music for days without touching anything.
If you like classical and electronics, this amp is made for you. Tight bass combined with good dynamics make an excellent combo, it’s never harsh and retains a lot of detail, even at lower volume. With a good headphone, it can get really low without getting muddy, even more on IEMs.

Treble is a bit too recessed for me, the female vocals are behind most of the time. Even if it’s harmless on major genres, it doesn’t deserve genres like vocal jazz. You can fix it with some equalizer but I don’t like to alter the signal. With the Sennheiser HD800S, you don’t have this problem, displaying how well this little amp can shine with good headphones. Mids follow the same path, offering good texture and layering without compromising the neutral approach of the AD18. They can considered a little shy, never leaving the comfort zone to avoid distortion. Surprisingly, it works well with Hip-Hop, on “I’m Not Racist” from Joyner Lucas you get a perfect understanding of the lyrics, even though I usually have to focus hard.
Out of curiosity I plugged in the (in)famous Audeze EL-8 Closed back. With a total lack of low mids/bass, listening really took a turn for the worst, leaving me dizzy and sick. Really !
The synergy never happened, at any point, even with the bass raised to +8dB. It was an awful yet interesting experience, gut shaking.

Speakers output

I know, Headfonia is a head- and earphone review website. So we should speak about headphones right ? But please, bear with me on this one, because when you plug some speakers, the SMSL AD18 really shines.

For something this small, it’s nothing short of a miracle really. I tried floor standing speakers and bookshelf speakers, always with a subwoofer since the amp offers the possibility. The amp even has banana plug connectors, sadly it’s the 2.5mm banana plug so you may have to choose a thinner cable than usual. If 40W per channel at 8ohms doesn’t seem a lot, it’s plenty of power for most of the speakers on the market really. Even with floor-standing speakers, just be sure to get some sensitive speakers like Klipsh. The Full Digital system gives you the same feeling as driving an electric car, even at low volume you get a whole, powerful, sound.

There is no difference regarding the sound signature, it remains flat and neutral. Which, again, is a good thing for most audiophiles allowing the speakers to really express themselves. For this review, I stuck with a down to earth setup : a pair of Audiopro Bravo All room plus a Yamaha subwoofer. Bass is tight, really really tight. Something you only get with Digital amplifiers. It goes as low as your speakers can, without any distortion, and if you add a sub woofer you can really set-up a small 2.1 home theater.

Treble is still recessed, just like with the headphone output, but it sounds precise with no sibilance. Imaging is really good, with my stereo speakers I can picture the voice coming upfront and not from left and right. Don’t play too much with the treble settings, it’s not harmful but it’s not perfect. Mids sound full, balanced but most of all realistic. A lot of amps tends to put too much emphasis on the mids, creating a wow effect that slowly fades away, before becoming annoying.

With an external amp

I wanted to try a different DAC with the SMSL AD18, but since the amp converts even analog signal to digital, it’s a bit complicated. However, I tried it anyway.
I used the FiiO Q1 Mark II as a DAC and the Cayin IDAC-6. If the latter sounds much more well-bodied, the difference wasn’t really impressive. If you get this amp, you’ll have to rely exclusively on the embedded DSP. It’s not bad at all, but don’t except a magical leap like with a Mojo or any FPGA DAC.

Conclusion

Let’s wrap things up, is the SMSL AD18 a good amp ? Yes.
Is it a magical wonder, price wise ? Yes.
Should you get one for your desktop ? Yes… if you want to use speakers AND headphones. Although it’s pretty awesome as a DAC/Amplifier for speakers, if your primary use is headphones, you can get better sounding devices at a similar price.

The flat signature combined with a good power reserve make it a great entry level system. With plethora of inputs, you can connect almost everything and get an all-around amp. Desktop amp ? Yes. TV solution ? Yup.

All in all, it’s tough to find a real flaw. The SMSL AD18 is good at almost anything but not perfect with big headphones like my HD800S. If the bigger amp like the M9 sounds almost twice as good, we might have a killer. Time will show.

4/5 - (86 votes)
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A nerdy guy with a passion for audio and gadgets, he likes to combine his DAC and his swiss knife. Even after more than 10 years of experience, Nanotechnos still collects all gear he gets, even his first MPMAN MP3 player. He likes spreadsheets, technical specs and all this amazing(ly boring) numbers. But most of all, he loves music: electro, classical, dubstep, Debussy : the daily playlist.

6 Comments

  • Reply June 4, 2018

    andrew

    Back in the early 80s, when Adcom and other company as Marantz, Denon then Krell move their manufactures to a small province in China, I was very disappointed with their quality control then but decades have past, I have much more confidence in the made in China hi-fi products.

    As the matter of fact, I still prefer the made in Malaysia than made in China when buying hi-i gear these days. Having said that, Apple products are made in China. Krell and others also move their facility to China.

    Go to Red Rose Audio co. that owns by Mark Levinson the guy who can never build a circuit board if he has to bet his life on it. Most of his pre-amp were designed and built by John Curl and look at the price list of the stuff that’s made in China at the Kurson factory. I thought stuff coming out of China was suppose to have good, cheaper prices? But if its got Mark Levinson’s name behind it, then apparently not.

    I own several Ipod touch, Ipad, Iphone and now DAC/AMP made in China and have very please with their build quality and their quality control.

    Having said that, I don’t have much luck with the SMSL products. I wish SMSL can beef up their products build quality .

  • Reply April 22, 2019

    Brian

    Companies generally set prices based on what their customers will pay, not what their costs are. I’m sure Levinson is no different. Moving to China is done to improve profit, not reduce prices.

  • Reply June 8, 2019

    Ben Barren

    Great review! i have a smsl amp but no aux output and less inputs. I have an old lovely turntable by pioneer (only issue out the has the gnd component which if not dealt with makes the sound vibrate etc) but rather than use my old Harman Kardon amp I’d like a smsl or similar modern smaller amp – would U recommend this or other models and brands ? Thx great review……

  • Reply September 2, 2019

    Ron Tesselaar

    Good review.
    I’m using this amplifier for almost a year now and I’m a happy camper.
    I only use the digital inputs because that way you remain in the digital domain and that is where this amplifier performs at it’s best.
    It’s like driving an electric car; the power is available all the range. It’s impressive that even on real low volume you get a full and rich sound.
    For output I use a Triad System one set (also small and impressive)..

  • Reply January 8, 2020

    Sam

    I think SMSL AD18 is a very good amplifier as far as my subs are concerned. I never bought one, rather one of my friend gifted this amplifier for use. I plugged in for home use and also tried to test with my subwoofers in car. Both the cases it performed beyond my satisfaction. Good product to purchase.

  • Reply April 10, 2020

    Stuart Longair

    I have this wee amp and form music I feed Amazon HD through a Chromecast Audio hooked up via the optical input. I also have my TV sound into the other optical with a 3.5 mm optical adapter. I use my old Q Acoustic 2020 speakers which seem to be a great match. Lastly, I feed my headphones from the aux input connected to my phone via the 3.5 audio jack.

    Covers all bases and very good value for money IMHO.????

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