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iBasso D2 Boa Headphone Amplifier - iBasso D2 Boa Headphone Amplifier

By Stuart Andrews



  • Recommended by TR
iBasso D2 Boa Headphone Amplifier


Our Score:


The unit itself is a little corker, roughly the size of a cigarette packet, weighting in at 108g and clad in a hard-wearing, shiny metal casing with cool brushed-aluminium front and back plates. iBasso seems to understand that you won't want it scratched while out on the move, so the amp comes supplied with a leather carrying pouch.

The D2 is powered by a 470mAh Lithium Polymer battery, which you can charge via the USB socket on the backplate by flicking the charge switch from ‘off' to ‘on'. iBasso claims that the battery is good for 38 hours of continuous use, and while I've been too busy plugging the thing in and out of laptops, PCs and iPods to test this properly, I don't see any reason to doubt it.

Inputs, outputs and controls are kept deliberately simple, with a 3.5mm mini-jack input and matching output on the front, along with a volume knob which doubles as an on-switch, and a ‘gain' switch that you can set up for high-impedance headphones, and down for more sensitive cans. A single, blue LED tells you that the unit is switched on.

PC setup is equally simple. Just connect the D2 up via USB and Windows recognises it as a USB DAC and installs the necessary drivers automatically, with the D2 taking over from any integrated audio solution or soundcard. I wasn't been able to test with a Mac or Linux system, but I understand from other users that it works perfectly well with the former, at least.

iPhone owners should also be warned that - like most headphone amps and speaker docks - the D2 is susceptible to noise interference. Switch your iPhone into airplane mode if you want to enjoy your music to the full.

To give the D2 a run, I first reached for my second-gen iPod touch and my trusty Samsung YP-Q1, then grabbed as many pairs of headphones as I could lay my hands on. Taking the signal from the headphone output of both players to the D2, there's a definite improvement in audio quality with just about every pair of headphones I tried. The difference is less pronounced with the Q1, which runs slightly louder than the touch and has - I suspect - better output circuits, but overall you seem to get a stronger bass, clearer mids and, generally, a livelier sound when using the D2 than when relying on the player's built-in amplification.


April 23, 2009, 3:54 am

Thanks for the informative review Stuart - I am really tempted, but was wondering if you had a chance to listen to an ipod hooked up to this through a pair of Shure SE530s?


April 23, 2009, 2:53 pm

I'm afraid I haven't. Generally speaking, I found the improvement in sound with in-ear models to be less spectacular than with full-sized cans - partly because the in-ear 'phones tend (as a rule) to be easy to drive. I'm sure you'd find some difference, but whether it's 𧵝 worth of difference is another matter.

For anyone else out there, I've just been listening to the iBasso with the iPod and a pair of Sennheiser HD595s and the results are extremely impressive. Superb clarity, positioning and definition, as you'd expect from the Sennheisers, but now with a little added welly.

Shaun @ HiFi Headphones)

April 23, 2009, 3:29 pm

We've had some very enthusiastic comments from customers using amps like the iBasso D2 to drive IEMs.

In my experience it's worthwhile with high end in-ear earphones (like the SE530) if you feed the D2 from the Line Out Dock (30 pin connector on the bottom of the iPod). It's particularly effective with higher impedance models like the Klipsch X10 or Sleek Audio SA6.


April 23, 2009, 3:50 pm

To echo Shaun, I've always found the iPod/iPhones particularly poor at driving dual/triple/quad driver phones as they generally require more power (simple logic, no?). so a headphone amp - especially amplifying the line-out not the headphone jack - would be worthwhile.

I'm definitely tempted to get one of these for my desk at work - lossless audio files through a decent DAC will make me very happy!


April 23, 2009, 4:14 pm

As I type I'm listening to my iPod from its line-out, through a CMoy amp and into a pair of SE530s. I can confirm that the amp lends the audio a far more powerful sound, warmer in tone but far superior to what I get from the headphone jack - particularly at higher volume. My amp's actually a Penguin Royal, as featured in TR's 'Fire in the Head' article.


April 23, 2009, 7:00 pm

Shaun and Hugo are right on those points, and it's definitely worth experimenting if you have some high-end IEMs - particularly high impedance models. I didn't have any that were that expensive or that refined to hand during testing (by preference, I tend to use over-the-ear 'phones myself).

As I said in the review, the results I had with full-sized phones and the line-out on an iPod Touch were actually quite amazing, and I'm still listening to FLAC and Apple Lossless files through the iBasso from my PC nearly a week after writing the review (usually when I should actually be doing other things). If you have the cash, it comes highly recommended.

Carl Abudephane

April 23, 2009, 7:10 pm

To use the line-out 30 pin connector from the i-pod, what sort of cable would one require in order to get the best results?


April 23, 2009, 7:31 pm

@Carl: Depends how much you want to spend. A simple 3.5mm stereo cable from any of the myriad iPod docks will do the trick. At the other end you can spend $200 on an ALO Cryo cable. There's a lot of conflicting opinion on how much difference the extra money makes.

Here's the iBasso adapter: http://www.ibasso.com/en/pr... You can get these for around 㾸 with some Googling.


April 23, 2009, 7:33 pm

I've had my d2 for about a 6 months now and have loved every minute of, especially paired with my Grado's.

I have a pair of Phonak PFE's which have a relatively low impedance rating and they are almost brought alive when using with my 5g rockboxed ipod, heaven.

For LOD's you can;t go far wrong here http://www.aloaudio.com/sto... and here http://www.qables.com/shop/...


May 27, 2009, 3:49 am

Comedian - Wich Grado's have you been using with the d2?

This amp looks very atractive. Im on my way to order some Grado SR80 and I have been thinking about getting a nice amp to get a good sound, it's just that I have been suffering because some say that they don't need to be amplified at all. I also have consider the Total Bithead amp from the guys from Headroom but it seems that the Ibasso is a better one.


May 29, 2009, 3:10 pm

Ive measured it's performance based on the USB DAC. It is important to notice that the first analog stage after the dac clips with 0dBFS in, it's unclipped with -3dBFS in (or below).

In plain words - you need to set the volume in your playback application to maximally 71%, ie the volume in media player or winamp. Else it will clip.

Maximal not-too-distorted output (if you plan driving a poweramp or active speakers with it) is 1.2Vrms


October 29, 2009, 2:54 pm

The real question is whether the Lithium Ion battery is replaceable. Otherwise the whole thing is useless in a couple of years. There is a monstrous conspiracy of silence regarding this nowadays.


May 7, 2012, 2:30 pm

I like the monster headphones, the sound headphones price what kind?

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