SMSL IQ DAC/Amplifier Review

Apple started the trend of removing the headphone jack in 2016 starting with the iPhone 7. Since then many Android device manufacturers have jumped on the bandwagon, ditching the 3.5mm headphone jack and outputting its audio via USB. This despite the fact that Android has not received an update to its USB audio feature set since version 5.0 Lollipop back in 2014.

According to Google’s official documentation, Android 5.0 (API level 21) and above supports a subset of USB audio class 1 (UAC1) features with the audio output limited to 48kHz similar to that of the iOS, even though the music app is playing 192kHz. Therefore, in order to enjoy hi-res audio files on Android devices, one has to either purchase an Android device with a 3.5mm headphone jack or connect the Android device to an external DAC either via USB or Bluetooth.

SMSL IQ DAC/Amplifier

SMSL (Shuangmusanlin) IQ is the company’s second-generation DAC/Amplifier. A portable device, the SMSL IQ is designed as a companion for Android smartphones or laptops.

Shenzhen SMSL Electronics Co., Ltd. is an established electronics manufacturer based in Shenzhen, China. Founded in 2009, SMSL specialises in the research and development as well as the production of digital-to-analogue converters (DACs), headphone amplifiers and power amplifiers. The company’s R&D division is led by an experienced team of electronics engineers and owns its manufacturing facility.

Design and Build

Available in black, gold and silver. The SMSL IQ weighs in at just 84g and measures 95mm (L) x 56mm (W) x 9 mm (H) in dimensions. The DAC/Amplifier sports a high precision CNC all-aluminium anodized sandblasted solid matte finished casing coupled with a carbon fibre finished bottom panel in a form factor that caters for better handling and stacking. Aesthetically, I am a bit disappointed by the use of screws to secure the bottom panel to the aluminium case, using adhesives instead would enhance the finishing significantly.

The volume rocker which also acts as a function button is placed horizontally across the front panel together with the Micro USB input jack, the 2.5mm headphone jack as well as the 3.5mm headphone jack.

The top of the device features an OLED screen which will display the volume as well as the audio output at all times. Located below the screen is a LED indicating the charging state of the device (red for charging and blue when it is fully charged), right below it is the Power button. A short press on the power button will temporarily toggle the display to show the power gauge while pressing the volume rocker will enable function toggling between the following:

• Charge (On/Off – to prevent the device from draining the battery of the source device)
• Output (Output selection between 2.5mm (BAL) and 3.5mm (UBAL))
• USB-MO (USB Mode selection between USB 1.1 and USB 2.0)
• PCMFLT (PCM Filter selection between fast, slow and mini)
• DSDFLT (DSD Filter selection between 47 kHz, 50 kHz, 60 kHz and 70 kHz)
• Dimmer (Screen brightness selection between 1 to 8)

When in the respective functions, rocking the volume rock left or right will allow selection toggling with the current function and selection displayed on the OLED screen. While the integration of function mode and selection toggling with the volume rocker is an interesting idea, it is a bit too small often resulting in multiple presses and can be cumbersome to use.

The implementation of a dual ESS SABRE9018Q2C DAC chip configuration coupled with XMOS xCORE-200 XU 208 allows the SMSL IQ to decode audio formats of up to 768 kHz/32-bit resolution PCM as well as native DSD decoding of up to DSD512 in USB 2.0 mode. The ability to decode at such high resolution brings great value to a product, although on some Android phones where USB 2.0 mode is not supported, the IQ will fall back to USB 1.1 mode, decoding audio formats of up to 96 kHz/24-bit resolution PCM. During the review process, I have tested the SMSL IQ on a number of Android devices which include the Huawei P20 Pro, Huawei Mate 20 X, Samsung Note 9, Xiaomi Note Pro as well as FiiO M6 and FiiO M9 confirming compatibility with Android 6.0 and above. Playback on PCs on both Windows and Mac OSX are seamless. However, on Windows, to enable USB 2.0 to support DSD playback, one must download the driver from SMSL.

Implementing Asynchronous Sample Rate Converters (SRC) using two ultra-low phase noise crystal oscillators ensures good phase alignment between input and output, while independent ultra-low noise low dropout (LDO) linear regulators for the left and right channel caters for minimal interference from the power supply to the respective amplifier chips. Rated at 55mW @ 32Ω on the unbalanced output as well as 91mW@32Ω on the balanced output. While the unbalanced output is more than twice that from an average smartphone, it should only be sufficient to power efficient earphones. For earphones which are either higher impedance and/or lower sensitivity, I would suggest one to use the 2.5mm balanced output. As the output ratings of the IQ is rather unimpressive, I would discourage pairing it with high impedance and/or lower sensitivity earphones.

Battery life of at least 8 hours is a benchmark at Porta-Fi to consider that a device is truly portable, particularly when it is a companion to a digital transport or source. SMSL did not provide any details pertaining to the capacity of IQ’s built-in battery, during the review process the IQ lasted an average of 8 hours and 37 mins while charging from flat took an average of 2 hours and 43 mins.

Included in the box alongside the DAC/Amplifier is a Micro USB to Micro USB cable and a Micro USB to USB Type-C cable.

Part 1: Introduction, Design and Build
Part 2: Sound Quality
Part 3: Product Specifications
Part 4: Review Ratings, Summary