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iBasso D2 Boa Headphone Amplifier review




  • Recommended by TR

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iBasso D2 Boa Headphone Amplifier
  • iBasso D2 Boa Headphone Amplifier
  • iBasso D2 Boa Headphone Amplifier
  • iBasso D2 Boa Headphone Amplifier
  • iBasso D2 Boa Headphone Amplifier


Our Score:


It's fair to say that, for many of us, a serious, separate headphone amplifier like the iBasso D2 is the kind of luxury we think we can do without. Whereas a bargain-basement device like a Cmoy amp or the much-loved FiiO E5 is pretty much an impulse purchase, you need to be serious about your audio before you splash out £150 on a pair of headphones, let alone on an amplifier to drive them. The iBasso D2, however, leaves me pondering. Sure, I could do without it, but having heard my music with it, do I want to?

Let me explain. In the Hi-Fi world, headphone amps became popular because serious headphone aficionados felt that the built-in headphone outputs sported by most mainstream amplifiers didn't provide a signal that was clean or powerful enough to drive their favourite cans as they wanted them to be driven. A separate amplifier, tuned specifically to the needs of headphones, would provide a better result.

It was inevitable that this idea would translate to the world of PC and digital audio eventually. For one thing, the built-in amplification and output circuitry in many MP3 players doesn't have the power or the finesse to get great results from what you might call audiophile headphones, and can introduce unwelcome noise. For another, as more of us rely on PCs and notebooks as an audio source, the same can be true of the DACs and amplifiers built into our sound cards and motherboard audio chipsets. We might be busily ripping all our CDs to FLAC or Apple Lossless, but then we end up putting them through DACs, amplifiers and outputs that colour or even denigrate the signal before it even gets a chance to reach our headphones.

Cleverly, the iBasso D2 amplifier has a solution for both problems. First, it's a highly portable headphone amplifier, capable of taking the signal from a headphone socket or a line-level output and boosting it to suit the demands of even the most high-impedance stereo ‘phones. Secondly, it doubles as an outboard DAC and amplifier for PC and notebook use, using USB to stream the digital signal to Wolfson WM8740 and Texas Instruments PCM2706 DACs for processing and analogue conversion. You'll find the Wolfson chip inside high-end CD players from the likes of Kenwood, Onkyo, Rega and Cambridge Audio, so it's fair to say that you can expect a better sound than you might get from the your average integrated audio chipset.


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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