Heinz Electrodynamic Designs HEDDPhone TWO GT

The beauty of a velocity-based driver, rather than the standard pressure-based type, is only half the story with HEDDPhone 2 GT. With a pleated driver surface area up to three times larger than contemporary dynamic, planar or electrostatic headphones, HEDD's third coming is a benchmark of transparency and audio purity.

One of Hi-Fi speakers' most important technologies, the quality promised by an AMT tweeter has always been unquestioned, and HEDD made a full-range, full frequency response one possible with Variable Velocity Transform (VVT) in their first HEDDPhone.

Now, HEDDPhone 2 GT adds practicality with its build and design. 25 percent lighter than its predecessor, a patent-pending HEDDband smart strap system allows height, width, curvature and even the clamping pressure to be tweaked to individual head shape for a complete earpad seal – all with HEDDPhone 2 GT still built entirely in Berlin, Germany.

HEDD already impressed Head-Fi with the pioneering spirit of the AMT's creator, Oskar Heil, when releasing the first HEDDPhone. Now, bringing the HEDDPhone 2 GT up to 2024 standards of audio quality are specifically positioned layers of damping material around its AMT that yields extension up and down in frequency, as well as elimination of driver crinkling.

Rather than moving back and forth as a pressure-type transducer (like 99 per cent of conventional driver technology on the market), HEDDPhone 2 GT's AMT is pleated with magnetic force acting to laterally squeeze air out of the driver's folds as an accordion would – according it the tag of being a velocity-based transducer.

That allows air to accelerate towards the ear up to four times faster than a beryllium or diamond dynamic driver of huge rigidity and excursion might. But without the cost, or distortion associated. The AMT's ability to reproduce sound as it was recorded is unrivalled in speakers, and now in headphones.

HEDD's VVT technology varies the fold lengths to aid this AMT in producing low frequencies below this tweeter technology's typical threshold of 3Khz, for high-quality, fast and accurate bass. That's an upgraded AMT driver that still retains all of its old spatial advantages, namely excellent horizontal dispersion.

Because of that, HEDDPhone 2 GT produces real depth and a sound that truly sounds like it's coming from outside of the head – perhaps most fulfilling the claim that it's almost like listening to true speakers.

Additional air compliance really grants breathing room and soundstage over its HEDDPhone 2 sibling, for equally high fidelity just packaged differently. Similarly, included velour earpads allow you to swap with GT's stock leather units for a different tuning.

Coming in at 550 grams, HEDD's next major upgrade comes in the form of the HEDDband – lighter in construction, yet stronger and more ergonomic.

Built to be adjusted on two axes, the vertical dimension sees owners able to adjust wearing height and curvature via a patent-pending belt secured system. The horizontal dimension also sees width and therefore clamping pressure customisable.

So much thought has gone into turning HEDDPhone 2 GT not just into HEDD's most complete product, but one of Head-Fi's barometers of affordable quality made to last with every last detail considered. German-style. Built in Berlin, HEDDPhone 2 comes with a five-year warranty against manufacturer defects.

Its accessorisation is something else too. Spare earpads, two cables – one balanced 4.4mm, another 1/4" – and 4.4mm-to-4-pin-XLR adapter all come neatly packed in a travel case so that studio professionals and audiophiles alike may bring HEDDPhone 2 GT to work and to play in equal measure.

Reasonably easy to drive for decent amplification, HEDDPhone 2 GT's AMT is now 2dB more sensitive at 89dB/W. Portable behemoths like Cayin Audio's C9ii, Enleum's HPA-23RM and iBasso Audio's PB5 are plenty up to the task.

Desktop power will truly unleash this AMT, though. Think of Cayin's iHA-8 or Questyle Audio's CMA18 for that purpose. While HEDDPhone 2 GT's flat impedance make HA-6A, HA-300B MK. II and Feliks Audio's Envy all transformer tube amplifier candidates.

There is no ceiling to HEDDPhone's sound quality, and a step up to the Lina – one of the best synergies with dCS Data Conversion Systems' statement headphone amplification system – or Soul 170HA in no way overawes HEDD's flagship. The future is AMT, and the future is now with HEDDPhone 2 GT. 

After you check yours out, proceed to explore HEDD's other HEDDPhone concepts here, or view all our other headphones here.