This amplifier looks brilliant from the front. Layout wise the front of the amp is perfect. You can turn it on and off even with the headphone jack populated. The massive volume knob is a nice touch and makes it easy to adjust the volume to exactly the right level. There is one problem with the volume dial: there is no tactile feedback from the volume dial and the indicator is the same color as the rest of the knob. This makes it hard to see how much you have cranked it up and darn near impossible in low light conditions. Of course you could give it a little nail polish dot, but that does not make it prettier.
One of the things that gives this little amp a robust look is the oversized front plate, which is over 0.5 cm deep and has a semi rough surface. I really like the way the amp looks directly from the front. As soon as you move up a bit you can see the acrylic top and while it is cool that you can see all the components it does not drag the amps aesthetics in a positive direction. The top cover is removable so you can just grab a piece of sheet aluminum at the nearest hardware shop and then cut it to fit and drill some holes at the appropriate places.
The chassis is made of aluminum and is incredibly sturdy without being big or bulky for that matter. The only part of the chassis that is not aluminum is the acrylic top cover which lets you see the interior design of the amp and the tube socket.
The tube sticks out of the top of the amp by about 2.5 cm. When it is in operation the tube begins to glow which is a quite cool effect, the glow is of course mostly visible in a dark room, it is not like a 50 Watt light bulb or anything like that.
The main chassis of the Head-Direct EF1 is actually pretty small. It is about the same height as an AA battery. The slim design is very attractive and practical.
With every purchase of the Head-Direct EF1 you get two tubes. One brand new Chinese 12AU7 tube and one NOS (New Old Stock) RCA 12AU7. Since the RCA tube is not being made anymore you can only get them either second hand or NOS from an online dealer. Head-Direct has plans to carry a lot of different high quality tubes in the nearest future.
The RCA "Clear top" tube is by far the best of the two tubes supplied with this amp. I tested the amp with a lot of different headphones and the RCA sounded the best with every single one of them.
The power supply is a really heavy one with both cables soldered to it. So if you live in the EU you will need to buy a new plug and screw that on instead of one it comes with. During the course of my testing it only got lukewarm so I guess it has plenty of overhead capacity and a quite efficient design.
Like most headphone amps this one features a 1/4" jack on the front. Placed in the middle of the amp it is quite easy to access with the amp in use. The jack is of course gold plated and feels rock solid, just what you would expect from a $399 amplifier. All of the features on the front are really durable right from the on / off switch to the metal work and volume dial.
The back side features a set of RCA inputs and of course a jack to plug in the cable from the PSU. This amp has only one input and it is analog which means that it is ideally suited to be used with a quality CD-player or other device with its own DAC. The lack of the DAC means that you have to go out and invest in a DAC of some sort to use it with your PC. The best part about the analog inputs is that you get to choose which device you want to use it with unlike the Travagan's Green where you are limited to PC use. All through my tests I had this little hybrid amplifier hooked up to my Marantz CD6002 CD player. The two input jacks are mounted on the chassis which means that they are almost impossible to break under normal circumstances, it also helps to reduce the strain on the components when you are hooking up the cables.
The internals of the EF1 looks very tidy with a lot of big heatsinks to cool the power consuming op amps. Only quality caps used.
On the acrylic top there is a small greeting from the Head-Direct crew. The detail is quite anonymous and does not ruin the overall looks by that much.