Review and Build: Head "n" HiFi Objective 2 / O2 Desktop Headphone Amplifier

Firstly I would like to thank Head "n" HiFi for sending me this kit to review, they are an EU based company specialising in providing Objective2 amplifier kits and prebuilt amps/DACs. 

I was provided with the kit version of the Objective2 amp with add-ons to make it a desktop version.

*disclaimer: This sample was provided for the purpose of writing a review, no incentive was given to write a favourable review. All opinions expressed are my own subjective findings.

All can be found here:

Now a big part of this review was to document the build, so here goes. Firstly the outer casings and components are all excellent and everything went together smoothly, if you are quick you could have this amp built in about 3 hours. I took my time, and it was a very easy and enjoyable build, I followed this very handy guide:

I will point out a couple of the resistors have changed colours so I used my trusty multi-meter and it was smooth building. I did brush the board with flux before starting just to aid the solder flow, and washed it thoroughly with alcohol afterwards, this ensures nice clean solder joints.

Head "n" HiFi provide the guide to installing the RCA inputs and outputs too which I used:

First it is best to install the smallest components, such as resistors and diodes, then move on to the bigger components. It is easier to show with pictures (I did not need to install the DC socket on the board as it is mounted on the rear of mine, but did so to fill up the holes on the board).

Build quality is excellent, this obviously depends on the person who put the amp together and their soldering skills but it was all very easy to assemble. One of the great things about getting the kit is the possibility to set your personal gain settings. As I am using it with a JDS Labs OL DAC, I opted for 0/+4dB gain, as I want to be able to use it with IEM’s and full size headphones.

Now the desktop version has a couple more features than the standard, you get a rear mounted DC socket for the power, and also RCA inputs and outputs. The RCA outputs are muted when you plug headphones in. On the front you have the power button, gain button, volume knob, 6.3mm headphone output and 3.5mm input. Overall the layout is much neater than the standard Objective2 that has everything on the front panel.

Now a lot has been said on the Objective2, and it continues to be a very popular amp. I still recommend it a lot to people entering the hobby looking for a good first amp. What I really enjoy about my new Objective 2 is the desktop configuration, I can have it neatly stacked with my OL DAC with RCA’s on the back and a neat little reference desktop setup.

This amp does what it says on the tin, it amplifies the signal without adding any real flavour of its own; it is not a nice warm laid back flattering amp. It is well known the Objective2 is not the most powerful amp when it comes to pure output current, but it will drive most headphones out there with relative ease.

I have been using it with sensitive IEM’s, Grados, German Maestro GMP400’s (need high gain) and it lets you hear the headphones and not the amp. This amp is not about synergy, it lets you hear the sound of your headphones without colouring them, and for reference purposes it is excellent.

People who think this amp sounds bright, are just used to a warmer sounding amp, this amp does not enhance any part of the frequency range. As I said this makes it an excellent reference amp, but paired with my Grado SR60e in wood cups, it is a really enjoyable desktop amp. It even sounds great with my GMP400’s, but I do prefer the slightly laid back sound of my tube amp for those.

Conclusion: This amp was a fun project to build up; it gives you a real sense of achievement to see it fully built and sounding excellent on your desk. I love the way it stacks with the OL DAC from JDS Labs, it is an awesome stack that I thoroughly enjoy (however I do need to change the green LED on the DAC). Head "n" Hifi are a great company to deal with and if you are in the EU buying from them means no import tax, they are responsive to emails and a pleasure to deal with. They provide the full kit and it would be the perfect first DIY amp for many people. If you don’t feel that adventurous they offer fully built amps too.

Again if you use it within its limits it is the perfect all round amp, it won’t power the more hungry planar headphones out there, but powers anything from sensitive IEM’s to the Beyerdynamic T1 and Sennheiser HD800.

Sound Perfection Rating: 10/10 (cannot go wrong with an O2 amp, especially a desktop version)


  1. Got lot of information out of your review. I still can't decide what to buy for my HD650.

    1. I personally prefer the HD650 with a high quality OTL tube amp, but that's my preference


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