oBravo Audio HAMT-3 headphones with HPA-1 mobile headphone amplifier and TK-3 tuning kit

oBravo Audio HAMT-3
oBravo Audio HAMT-3


Have you ever heard of the German physicist Oskar Heil? Most probably, since we love the high fidelity, someone knows Heil’s tweeter and the ESS Transar loudspeakers, glorious factory in Sacramento, California. In the 70’s, ESS introduced in their designs a driver tweeter using Heil’s invention, the Air Motion Transformer - AMT: a thin layer of Mylar ribbon glued on an aluminium support, accordion-folded, capable of vibrating - under the influx of a magnetic field – quickly and with efficiency by moving the air five time quicker than a traditional electrodynamic driver. To be correct, of Oskar Heil – 1908-1994 – we should talk as a great scientist, at least concerning the development of the microwaves apparatus and for the theory of the modern field-effect transistor, FET. But what about the headphones? We are talking of headphones here. Well, be patient and keep on reading.


I am Unbelievable. I am Incredible. I am oBravo.

Dear readers, a slogan like this is quite demanding for a company! It creates great expectations that if not kept call for distrust and sarcasm in the end users.

At the oBravo Audio they must be very sure of their products! Judge yourselves by looking at their website. Top materials and, if not absolute news, very interesting and innovative technological solutions. The first interesting thing is the choice of making a two-way headphone. For the high frequencies a small AMT Heil’s tweeter – now you can understand the preamble! – and for the mid low a dynamic driver with a powerful neodymium magnet. AKG with the K340 had already tried the multi-way system by implementing an electrostatic tweeter. Such strategy, however, has not been frequent among the manufacturers, maybe for the costs and the complexity of getting a good balance between the two ways of emission.


From the technical point of view

Type: the HAMT-3 are over-ear headphones with a double way of emission, low impedance, 32 ohms, high sensitivity, 105 dB and a weight of 398 g. Therefore, they can be used in mobility with smartphones and multimedia player. If these devices have less capability of driving, they can be matched with the small but efficient mini mobile amplifier oBravo HPA-1. The materials have been chosen with care like Alcantara, the wood and the chrome of the headband. Handy and very nice is also the small backpack for an easier mobile usage.

Furthermore, oBravo commercializes a microscopic and cute tuning kit: the TK-3. You can operate a fine-tuning just using the cylindrical rubber seals in silicone for the HAMT-3. To get inside the HAMT-3 you have to remove the pads and extract, with care, the block of the drivers. At this point, you can insert in the three holes the silicon cylinders that, although not altering the general tone colour, they operate a modification in the listening.

The small mobile HPA-1 amplifier is enclosed in a solid aluminium shell machined with modern CNC techniques. It has a 1.200 mAh powerful lithium battery that lasts many hours before being recharged. In fact, after twenty hours of functioning I have not noticed any power decrease.

From a front view, from left to right: USB port for the recharger, three small LEDs that indicate recharge/end of recharge and apparatus on, 3,5 mm mini jack input and output, volume adjustment. There is also a 3,5 mini jack - mini jack connection cable.


Listening impressions

These headphones need a long run-in before being judged. Initially, they give a boxed sound. The two ways of emission stay for several hours “unstuck” with a gap on the mid frequencies. After twenty-thirty hours of functioning things start to change: the low frequencies gain articulation and depth, the mids come forward and the trebles gains fluidity and musicality. Without any doubt, the best performances are with mobile devices and outputs at low current level. The frequency response also after the run-in is a bit loud, hence suitable for sources with small lacks in the range extremes. With amplifiers capable of giving current without any problems, the low frequencies are quite cumbersome and unnaturally present so that the musical instruments lose their articulation. To solve this problem, very useful is the tuning kit. By inserting the silicon cylinders as shown, you can contain those annoying resonances in the lows, giving to the HAMT-3 headphones a more balanced tone colour capable of better supporting the energetic dynamic transients.

Remarkable is the response of the amp-headphone system with the oBravo HPA-1: a jewel! Also with more demanding headphones than the HAMT-3 the outcome has always been of great level.

Again: materials of top quality. The headband is perfectly adjustable but quite rigid. It could give some problems in long listening sessions.

Undoubtedly, the system HAMT-3 plus HPA-1 is suitable for mobility and for the musical genres where an absolute linearity of the system is not required to enjoy all the components of the sound message.



Do you like this system? It is nice and functional, absolutely trendy! With an amazing package. The performances are remarkable. Is the price too high? Yes, it is IMHO, but consider their unicity and do not forget the future offers for the single objects or for the bundle headphone plus amplifier. Bravo, Obravo!



Selection of listened music

David Bowie - Blackstar (LP-2016)
Chris Cornell - Higher Truth (LP-2015)
Cincinnati Pops Orchestra - Orchestral Spectaculars, Erich Kunzel (Telarc CD-2002)
Erich Kunzel / Cincinnati Pops Orchestra Featuring King' singers ‎- Perform Music Of The Beatles (Telarc SACD-2001)
Joe Jackson - Fast Forward (LP-2015)
Leonard Cohen - Popular Problems (HD Tracks 24/96 - 2014)
Mumford & Sons - Wilder Mind (LP-2015)
Of Monsters and Men - Beneath the Skin (CD-2015)
Placebo - MTV Unplugged (CD-2015)
Puscifer - Money Shot (CD-2015)



top score ✳✳✳✳✳ ReMusic Sparks

Tone colour: ✳✳✳✳ | A bit loud and with many basses. Remarkable the response at the extremes of the audio range. The AMT tweeter is well present.

Dynamics: ✳✳✳✳ | Very good with source with low level of current – mobile devices – less convincing with amplifiers without if and but in terms of driving capability.

Detail: ✳✳✳1/2 | Surely great on the high frequencies, of average on the rest.

Versatility: ✳✳✳✳1/2 | If you consider the great number of accessories, I would say great!

Image: ✳✳✳ | Improved after a long run-in, quite limited in all the spatial directions.

Rise time: ✳✳✳1/2 | More than good at low volume. It becomes a little worse increasing the volume.

Look and functionality: ✳✳✳✳| Beautiful, trendy and properly working.

Price/quality ratio: ✳✳✳ | The product deserves attention and is very beautiful. The price should be reconsidered in a commercial logic with a fierce competition like in this sector.


N.B. The Spark judgement refers to the match HAMT-3 headphones and HPA-1 mobile headphone amplifier.



Official technical specifications

oBravo HAMT-3 headphones

Frequency Response: 20Hz~45KHz

Tweeter: 40mm Air Motion Transformer Tweeter

Dynamic Driver: 50mm

Impedance: 32ohm

Sensitivity in dB: 105dB

Weight: 398g


oBravo HPA-1 mobile headphone amplifier

Dimensions: 115x20x56mm (WxHxD)

Weight: 190g

Battery: 1.200mAh lithium rechargeable battery



Official Italian dealerto MondoAudio website

Official current price in Italy: oBravo HAMT-3 headphones 850.00 EUR, HPA-1 mobile headphone amplifier 490.00 EUR, TK-3 tuning kit 60.00 EUR

Associated equipment: to Mauro Cittadini’s system

by Mauro
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