This will probably go very cold, as it's too specialised a gizmo, but hopefully the right people will see it, if they are unaware. Normally I wouldn't post anything from Deal Extreme, but this is a bit different, and probably a bit special, so I decided to give it a go. I have already preordered mine. It's below the threshold for customs to bother with, which is always a big plus.
Taken from FiiO's website:
E5-portable headphone amplifier
Worlds smallest metal case headphone amplifier
E5 is a Portable Headphone Amplifier designed to improve the sound quality and volume of any Digital Audio Player such as a MP3 or MP4 Player, Mobile Phone, Laptop, or Notebook. It is an upgraded model of E3 Headphone Amplifier which is very popular around the world. It retains all the advantages of the E3, and yet still has very small slim case! Now with a volume control so you can connect directly to the line out of a Digital Audio Player and control the volume directly!
But it is more than just an upgraded version of the E3! It has a higher power output, better Signal to Noise ratio and Lower Distortion! And with the new TIs headphone amp solution, E5 have better sound qualilty and can work better with high impedance headphone. With a sound effect switch which will remove any Bass Boost., E5 will be a good pair with more different headphone.
●Designed for high impedance and low sensitivity headphones,
●Easy to carry and use in the outdoors
●Increases your music player's play time
●New amplifier IC, with higher S/N and lower distortion!
●Very high PSRR, and with metal case. Reduces the noise caused by GSM mobile phones! So you can now connect to a GSM music mobile phone!
●Individual power switch;
●Electronic volume control, ( means very low distortion and avoids the adjustment noise caused by a potentiometer);
●Two sound effects: Flat and bass boost mode;
●Built-in Rechargeable battery, gives about 20 hours playtime at normal volume;
●Mini USB charger port!
●With a built-in metal clip, you can clip the E5 onto anything !
Output Power: 150 mW (16 ohms Loaded)
12 mW (300 ohms Loaded)
Signal to Noise Ratio: >= 95 dB (A Weight)
Distortion: < 0.009% (10 mW)
Frequency Response: 10 Hz - 100 kHz
Suitable Headphone Impedance: 16 ohms - 300 ohms
Power Supply: build-in 200mAh rechargerable battery
Dimensions: 44.2mm x 38 mm x 12.6 mm
Pre-amp: OPA2338UA From TI (Texas Instruments)
Power-amp: TPA6130A From TI (Texas Instruments)
15cm 3.5mm to 3.5mm audio line *1
80cm 3.5mm to 3.5mm audio line *1
60cm USB-A to mini USB charge line *1