IKKO ITB03 Heimdallr Review

IKKO ITB03 Heimdallr review featured

The IKKO ITB03 Heimdallr is a portable Bluetooth amplifier. It features dual AK4377 DAC chips, 4 digital filter modes and supports all your favourite Hi-Res Bluetooth codecs like LDAC/aptX/aptX HD/aptX Adaptive. It can also be used as a desktop DAC. The price is $142.

Disclaimer: This sample was provided by IKKO for an honest review. All observations and opinions here are my own and are based on my experience with the product.

IKKO ITB03 Heimdallr Review
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Clean robust sound
Good staging
Design and build quality
OLED display
Can be used as a Bluetooth or desktop DAC
LDAC and aptX HD supported
Minimum volume is too loud
No auto power-off function
No audible prompts for Power On/Off etc
No case or cover included
Our Score

IKKO ITB03 Heimdallr

  • Bluetooth Chip: QCC5125
  • Bluetooth version: 5.0
  • DAC Chip: AK4377*2
  • USB Interface: XMOS XU208 AMP: RT6863*1
  • Volume Level: 100
  • Output Power:PO:32mW (32Ω loaded)               BAL:125mW(32Ω  loaded)
  •                           PO:53mW (16Ω loaded)               BAL:180mW(16Ω loaded)
What’s in the Box
  • IKKO ITB03 Heimdallr
  • USB-C to lightning cable
  • USB-C to USB-C cable
  • USB-C to USB-A cable
  • User manual/warranty
IKKO ITB03 Heimdallr design


The IKKO ITB03 Heimdallr has a black aluminium chassis with 2.5D curved glass panels on the front and back. It’s a classy-looking device although the glass panels tend to pick up fingerprints quite readily. Sadly, there’s no included plastic case or cover, however, the unit feels robust and has held up well during testing.

The front panel hosts an OLED screen that displays useful information such as connection method, battery level, decoding rate, volume, track title, audio mode and dynamic pickup. The rear panel has an NFC logo for touch pairing.

All of the onboard controls and built-in microphone are located on the right side. There are 4 buttons in total: Button+, Function key, Button-, Reset button and Power button.

On the top side is a 4.4mm balanced headphone jack and a 3.5mm single-ended headphone jack. The USB-C charging port is located on the bottom.

ITB03 rear panel with NFR logo

Internals and Hardware

At the heart of the ITB03 are dual AKM AK4377 DAC chips in charge of decoding and an XMOS XU208 USB interface. The ITB03 supports up to 32-bit/384kHz. A Qualcomm QCC5125 takes care of the Bluetooth 5.0 duties. Bluetooth codecs supported include LDAC/aptX/apt HD/aptX adaptive.

Output power is modest but sufficient. The ITB03 pushes a mere 32mW@32Ω from the 3.5mm headphone jack and 125mW@32Ω from the 4.4mm balanced headphone jack.

You can expect around 8 hours of battery life from the ITB03 which is a bit less than I expected considering the size of the device. The 650mAh battery takes around 1.5 hours to fully charge.


The IKKO ITB03 Heimdallr comes with a lot of functionality. It can be used as either a wireless Bluetooth amp or as a wired desktop DAC. It supports both UAC 1.0 and UAC 2.0 so it’s compatible with some gaming systems as well as modern computers.

All of the music playback controls are done with the side buttons. You can adjust the volume, play and pause music, as well as skip to the next or previous track. The volume can be adjusted in steps via single presses or you can ramp it up and down by holding down the respective buttons once the volume interface is open.

The menu can be accessed by holding down the power button for 2 seconds. From there you can select the digital filter, high and low gain modes, car mode, charge On/Off and screen brightness. This is also where you can switch between Bluetooth (Music) and DAC (HiFi) modes.

You can also use the ITB03 for phone calls thanks to its built-in microphone. Lastly, a short press on the power button switches the OLED display On or Off.

IKKO ITB03 Heimdallr Bluetooth amp OLED display and IEMs


Gear used for testing includes the Tin HiFi T2 DLC, SIVGA Oriole and Letshuoer S12 Pro.

Some people reading this might be familiar with the AK4377 DAC as it was used in similar devices including the FiiO M5 and 7Hz 71. The DAC chip utilizes AKM’s VELVET SOUND technology that promises to deliver “a faithful re-creation of the original experience, as if you were there.”

There’s a slight lift in the bass that gives the sound fullness without giving up any details. Mid-bass notes are tight and punchy and the sub-bass has a smooth but deep rumble. I cue up Porcupine Tree’s ‘Russia On Ice (2007 stereo mix)’ and the kick drums are thick and delivered with ample impact. The stage is deep and not especially wide but there’s good layering throughout. Later in the song (9:28), the sub-bass notes kick in with a satisfying but clean rumble in my ears.

Next, I cue up Dario Marianelli’s ‘Mrs. Reed is Not Quite Finished’ and can’t help getting caught up in the sweeping strings. The ITB03 faithfully reproduces them with clarity and gravity. Notes trail off naturally into the air with a neutral tone but the slight bump in the bass gives the low cello notes extra grandeur and solemnity.

‘Bruca Maniguá – Live’ by Buena Vista Social Club opens with the sounds of the crowd murmuring and a few random notes from the double bass. With the IKKO ITB03, you immediately get a sense of the scale of the venue and the energy in the air. When Ibrahim Ferrer walks onto the stage, it’s impossible not to feel the excitement of the crowd almost as if you were there. The vocals, piano, horns and the whole atmosphere are electric and the ITB03 conveys the feeling but is reserved enough to keep it all held together cohesively.

ITB03 Bluetooth amplifier


The Bluetooth amplifier space is an exciting one, especially considering the way wireless music is steadily improving. It’s good to see new additions like the IKKO ITB03 Heimdallr that offer good functionality and quality audio enter the fray. This is a good item to have, especially if you are someone who wants added features like car mode and always-on display.

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