SMSL Idol+

Review Date: 12 February 2022


Input: Micro USB
DAC Chip: VT1620A
Output: 3.5mm headphone jack
Dynamic range: 97dB
SNR: 85dB
Channel separation:  85dB
THD+N: 0.025%
Sampling Rate: 16bit/192kHz,24bit/96kHz
Power consumption: 0.1W
Headphone amp chip: MAX97220A
AMP power: 64mW(64Ohm@1%THD+N)
Supply voltage: 5V
Weight: 56g
Size: 55x21x8mm


  • FOSTEX T40RP MK3 (Magnetic Planar, 50 Ohm, 91db Sensitivity)
  • Beyerdynamic DT880 (Dynamic Drivers, 600 Ohm, 96db Sensitivity)


  • Etymotic ER4SR (Single BA, 45 Ohm, 96db Sensitivity)
  • TRN VX Pro (8 BA + 1DD Hybrid, 22 Ohm, 106db Sensitivity)
  • TIN HiFi T3+ (Single DD, 32 Ohm, 105db Sensitivity)
  • Kinera Idun Golden (3BA + 1DD Hybrid, 32 Ohm, 112db Sensitivity)


  • Windows 10, Foobar 2000 (USB 3.0 Power)
  • LG V50 ThinQ (UAPP USB Exclusive Mode, Bitperfect)
  • Sony Xperia X Compact (UAPP USB Exclusive Mode, Bitperfect)
  • HiBy Music Player App (USB Exclusive Mode)


SMSL Idol+, I purchased this unit purely out of curiosity to find out how does a 2016 Dongle sounds like. The other two examples of 2018-2017 releases (CEntrance DACport HD and Apogee Groove) has been quite a revelation to me, those two being absolutely classy and relevant still to this day, with DACport HD being the reigning champion of #donglemadness

However, after several sessions with SMSL Idol+, the same cannot be said of this unit. It is quite apparent to me this one lacked many things that I would consider as a great Dongle. For one it has very weak power and then somewhat odd technicalities.

Truth be told, that early impressions remained the same later on and as such I am not as excited to write too much on this archaic Dongle.

Build, Functions, Usability

The build of Idol+ is quite neat and compact. It has three buttons on the body itself to facilitate for volume adjustment. But those adjusters are not independent and will directly change the volume levels on the host

Idol+ comes with USB Micro to Micro cable and this alone will prove quite a pain nowadays. Suffice to say I skipped the stock USB cable altogether and use my own USB-C to Micro (from my DACport HD) to run it on my phones and laptop

Battery endurance of SMSL Idol+ proved to be quite impressive, it scored 9 hours of continuous operation on my Sony Xperia X Compact (Android 8, 2700 mAH, UAPP bitperfect mode, Low Gain driving TRN VX Pro). This is like 3 hours more mileage than most modern day competitors.

Sound Impressions

What I do like about this Idol+, it is definitely analogue and organic in timbral presentation. The overall sound balance being neutral and totally uncolored.

As heard using my Etymotic ER4SR, I can clearly hear how natural the tones are. There’s no added coloration to any of the sound frequencies. However it must also be noted that this sort of sound signature may not be perceived as “Hi-Fi” by current standards which seems to favor bright, highly resolving and transparent presentation. But for those appreciating a more classic feel to the output, Idol+ will fit the bill just nicely.

I am hearing good note weight and dynamics density for Mids. Again it appeared to sound very organic and “warm”. Definitely not dry or artificially resolved. With Mids centric partners, this is quite evident. The output being intimate and very forward in staging. However despite all that, I also observed the tendency for Idol+ to sound slightly honky and nasal with some tracks – as if there’s a hollowness to the rounded exterior, if that makes any sense.

On the higher frequencies, Idol+ is moderate at best. Even paired with my ER4SR, I can feel that Treble extensions being rolled off with lack of extended decays and air. There’s ample sparkle and textures, but they are very subtle to what I am used to. One thing for sure, Idol+ will never sound harsh or sibilant. It is as smooth as it can be with the Highs.

Lower frequencies, admittedly sounded dull to my ears. I did mentioned earlier that this Idol+ is a neutral sounding unit, but it also mean Bass responses lacking the depth and density as well. Extensions audibly rolled-off and prompt. At least it clean enough to sound realistic. Sub-Bass is barely audible at all, Mid-Bass being flat and uninspiring. Not that I am a basshead, I am a Diffused Field Neutral junkie, but I do prefer my Bass to be rich in depth and density – like what I am hearing from DACport HD or Ovidius B1.

Technically, lets just put it this way. Idol+ is a musical unit. It lacked many things that would be considered as technically excellent. For one, the soundstage is somewhat cramped in and lacking sense of space. Even more worrying, spatial staging and imaging being Left/Right centric. It is not holographic at all, definitely. The overall presentation reminds me a lot of traditional Stereo of the 80s. Not exactly a bad thing but then after being spoiled with current trend of expansive and holographic sound, Idol+ feels sort off underwhelming in this regard.

Details, speed, resolution and transparency is moderate to say the least. Idol+ is not to be used for analytical listening, but will still work fine for casual music enjoyment.

Driving Power

I will make this simple. Initial tests with two of my juggernaut headphones, Fostex T40RP MK3 and Beyerdynamic DT880 600 Ohm was enough to convince me to NEVER use Idol+ with anything demanding. Idol+ simply lacked the power to drive anything above 64 Ohms, or sensitivity lower than 100db.

The majority of my tests were done with the ER4SR being the heaviest to drive. The result were MUCH better with highly efficient partners like TRN VX Pro and TIN HiFi T3+. Both IEMs being very efficient and sensitive. I would even say that the saving grace for Idol+, the synergy with highly sensitive stuffs. The background being clean and quiet. The overall dynamics seems to be a lot better too. It is rich and wholesome as it can be. Suddenly all the cons mentioned earlier seems far fetched and distant.


SMSL Idol+. This dongle need to be looked from two angles. One angle, pairing it with anything demanding will just won’t work. The output being underwhelming and uninspiring. Flip the coin and keep it to below 50 Ohm (32 Ohm and lower preferably), and suddenly the other angle of Idol+ will emerge. Now with suitably efficient partners, the sound is pleasantly musical and rich. Technicalities seemed to improve in spades as well.

All in all, with the options available nowadays, SMSL Idol+ exist to remind us how far Dongle tech has evolved. What was lacking in power, now we find many top tiered Dongles being able to drive even 600 Ohm monstrosities. Keeping Idol+ to highly efficient partners is the key to keeping it usable and relevant.


  • Well balanced neutral and organic timbre, smooth presentation
  • Analogue and musical when paired with easy to drive partners
  • Very impressive battery drain to the host
  • Works great with HiBy USB Exclusive Mode and UAPP


  • Volume adjustment not as refined as the competitors
  • Volume adjusters not independent
  • Underwhelming technicalities when paired with demanding partners
  • Micro USB

⭐⭐⭐ ($39.99)

Best Pairing: Partners not exceeding 50 Ohms, preferably 32 Ohms and below, sensitivity above 100db.

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