| » »
The "Caffeine" Headphone
The "Caffeine Ultra" Amp is truely a high fidelity
amp at the lowest price possible. It uses the amazing AD8397 opamp and two TLE2426
railsplitter to create the virtual ground. Furthermore, it includes two slide
switches for gain and bass boost (8dB). Advanced customers agree: If this amp
would be housed in a "commercial" enclosure the price could be raised up to
Superior Sound Quality
The amp is equipped with the newest generation of high performance
audio amplifiers--the AD8397
opamp. Standard "CMOY" based amplifiers use the OPA2134
opamps which are capable of providing 25mA output current only (without buffers).
The AD8397 is capable to provide 310mA output current with
excellent linearity. Could you imaging how much better this opamp sounds? If
you had compared this amp to the standard CMOY amp you would never want to hear
a CMOY amp again!
The design of this amp is superior to others as it uses
a professional circuit with two Keystone battery connectors. There are no
loose cables to clutter the inside of the amp, and the Keystone connector
holds the battery securely. Even when the amp is moved or flipped over the
battery stays in place.
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 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 amp charges all 7.4 or 8.4V rechargebale batteries with
a so-called trickle charging that forces a constant current (35mA) into the
battery. A completely flat 250mA rechargeable NiMH battery will be charged in
8-12 hours and will last more than 15 hours using Sennheiser's HD650 at very
load play back.
Attaching the Amp
The amp comes with four pair velcro dots. Four "Loop" dots
are already sticked at the bottom. They look very nicely on the amp, safe
the buttom from getting scratched and they can be used to attach the amp
to any surface (player, laptor, desk etc.).
Key Features and Components
- AD8397 high performance opamp
- LM6171 ground driver
- adjustable gain of 2.5x (8dB) and 9.3x (19.4dB)
- 22 ohm output resistors (to reduce sibilance when using lean headphones)
- detachable bass boost of 7.3dB in low gain and 9.4dB in high gain
- trickle charging using LM317 constant current of 35mA (10 hours charging time)
- black circuit board with chemical nickel-gold letters (no silk print!)
- toggle switch by NKK Nikkai
- 1/8'' (3.5mm) audio jacks
- blue low current LED in a silver housing
- 9mm volume potentiometer (low noise)
- aluminium volume knob with durable rubber rings
- 1% SMT resitors thin film type
- low-ESR 820µF power cap (FM Panasonic series)
- 9V battery connectors by Keystone
- size with knob: 2.44" wide X 4.45" long X .95" thick (6.2 x 11.3 x 2.4 cm)
Not available now. What about the Arrow headphone amp?