Be aware that the newest generation has a BLACK circuit board with golden letters in a BLACK tin.

This cool little amp in a Penguin tin looks like a traditional "Chu Moy" -- but as you can see on the interior pictures to the side this amplifier is much more professional engineered than any other amp in this 'tin' style.

The heart of this amp is the rail-to-rail AD8397 opamp for amplification and two TLE2426 railsplitters for creating the virtual ground. The AD8397 opamp is much better than the common cmoy used opamps OPA2134 or OPA2277 (those opamps need output buffers to sound their best). The AD8397 is capable of driving heavy loads with excellent linearity. It has low distortion, high output current and a wide dynamic range -- while consuming less battery current. High impedance headphones like Sennheiser's HD650 are perfectly driven as well as low impedance phones like those by Grado. Even IEMs (in-ear-monitors) are well suited due to the amp's low noise. Sonically the amps has tight (but not over imposing) bass & drums, crisp (but not annoying) highs and a neutral yet detailed midrange.

Bypass Power Switch

An absolutely unique feature of this amp is the bypass ON/OFF switch. Normally a headphone amp shuts down the music when it is turned off. This amp however bypasses the internal electronics so you can hear the unamplified music of your player. Turn the amp on if you need more power; turn it off if you don't need the amplification -- you will never need to change the connected cables! As a result, you are able to hear the difference between amplified and unamplified music immediately! Also, the 3-pole toggle switch flips harder than the 1-pole switch so it won't trigger accidently in your pocket!

Hooking up the amp

On the left side you will find two audio jacks for input/ouput. They are indicated on the blue circuit board so you can't confuse them (it doesn't matter if you do though). In the middle of them you will find the volume control which consist of a nice silver knob with two black rubber rings. On the front side there is the ON/OFF toggle switch and the blue power indicator LED. Inside the amp you have access to the DC-in jack and to one 9V battery clip-on lead. The battery is holded between the golden caps and the rubber foam on the right side.

Powering the amp

The amp needs one 9V battery for powering. You can expect 40-60 hours of battery life using alkaline batteries. Rechargeable batteries will last about 20-30 hours (depends on the battery type, music and headphones). Optionally a 9-18V DC external wall adaptor can be used to power the amp (the battery and the adaptor are not included).

Battery Charging

The amp charges all 7.4 or 8.4V rechargebale batteries with a so-called trickle charging that forces a constant current (30mA) into the battery. A completely flat 250mA rechargeable NiMH battery will be charged in 8 hours and will last more than 25 hours using Sennheiser's HD650 at very load play back.

Attaching the Amp

The amp comes with four pair velcro dots that allow your to stick the amp to any surface (player, laptor, desk etc.). Four dots are already sticked at the bottom of the amp that also protect the amp from getting scratched (and they look very nicely on the amp).

Features

- AD8397 opamp
- 2x TLE2426 railsplitter
- blue circuit board with golden letters
- 3-pole bypass switch by NKK Nikkai
- blue low current LED in a silver housing
- Alps volume potentiometer
- 1% SMT resitors thin film type
- trickle charing using LM317 constant current
- big 3300µF 'FineGold' caps by Nichicon
- 9V battery connector by Keystone
- 2.44" wide X 4.45" long X .95" thick (62 X 113 X 24mm) including knob

Accessories

There is no accessory included (except 4 corresponding velcro dots "Hook"). To hook up the amp to your player you will need a mini to mini 1/8'' to 1/8'' (3.5mm) interconnect cable (see the accessory category). To connect the amp to your computer you will need my unique USB DAC cable (includes a digital to analog converter). To power and charge the amp you will need a 12-18V external AC power-supply/charger (plug: center positive, 5.5/2.5mm). Finally you will need a 9V battery (rechargeable or non-rechargeable) to power the amp on the road. You can get this from your local electronics store.