RAL KEB02AK Balanced Headphone Amplifier
The RAL KEB02AK balanced headphone amplifier was designed as a companion for portable media players such as the Astell & Kern AK100 and AK120.
With it's 2 digital inputs, one for toslink and one for coax SPDIF input, it is an ideal add on to your portable media player which does not have enough power to drive more demanding headphones.
Dual operation mode enables to you to connect to various music source devices.
The brand new ESS SABRE32-2M ES9018K2M DAC allows you to enjoy a finer, more crisp sound.
Includes dual separate headphone jacks for balanced output and single end output.
Battery life varies depending on connection type and load. But for example the battery will last 5hrs. to shutdown when continuous playing with SONY XBA-40(8 ohms) earphone and iPad Mini. It requires Aprox. 2hrs.45min. to be charged fully.
Equipped with a Digital Filter Switch
With the KEB02AK, it is possible to change the settings of the digital filter which is mounted on the built-in DAC (ES9018K2M) to fit connections to headphones or earphones of your liking.
The built-in power supply of the REX-KEB02AK uses lithium-ion rechargeable battery enabling continuous playback around 10 hours on a full charge.
When coaxial input / balance connection (played in 300Ω load volume 12:00 position). When USB output corresponding AC adapter is used, it will be fully charged in about 3 hours. If using the USB port of the PC, to charge the unit, it will take more than 3 hours to charge the unit. To balance the headphone output of this product, when you connect headphones or earphones, remodeling or replacing the input plug is required. The KEB02AK uses the sampling clock and jitter removal features that are built into the DAC.
Includes digital input (S / PDIF coaxial and optical)
Connect the Astell & Kern AK120 or AK100, CD players or other digital output devices to enjoy on the go listening.
The KEB02AK can also be used as a home or stationary device so you can enjoy fully balanced music at home.
Corresponding input format:
Digital coaxial: 24bit / 16bit, 192kHz ~ 44.1kHz
Digital light: 24bit / 16bit, will be 192kHz ~ 44.1kHz.
Balanced and Single-ended Output
Balance headphone output: 2.5mm micro mono jack × 2
Single-ended stereo headphone output: 3.5mm stereo mini jack × 1
Push-pull balanced headphone drive circuit with BTL connection
The balance headphone output uses TI TPA6111 for each left and right channel in the BTL connection with full balance configuration.
There is excellent channel separation with the balanced drive with crosstalk characteristics and a sense of separation in the connected earphone / headphone.
Adopts TI made TPA6138A2 for single-ended output
Implement the independent analog filter with TI made TPA6138A.
The KEB02AK reproduces excellent acoustic space with the OCL output due to balance input and DirectPath.
The adopted OCL circuit that does not use the output capacitor. There is a natural sound quality with no exaggeration in the lows.
Uses a lithium-ion rechargeable battery
The built-in power supply of the REX-KEB02AK uses lithium-ion rechargeable battery (3.7V / 1,200mA) enabling continuous playback of about 10 hours on a full charge.
When USB output corresponding AC adapter is used, the KEB02AK will be fully charged in about 3 hours. Like the USB port of the PC, in charge of a small USB port of the output current, it is necessary to charge more than three hours.
To balance the headphone output of this product, when you connect headphones or earphones, remodeling or replacing the of input plug (Li cable is limited to those possible) is required.
KEB02AK uses the sampling clock automatic follow-up generation and jitter removal features that are built into the DAC.
Audio output, equipped with two systems of balance headphone output (2.5mm micro mono jack × 2) and stereo headphone output of a single-ended (3.5mm stereo mini jack × 1). By utilizing the optional optional cable, it is possible to enjoy music in full balance in the portable environment.
In addition, it is equipped with a digital filter selector switch on the front body. to fit to the connected to headphones or earphones, you can enjoy by switching the digital filter that is installed (Slow / Sharp) to the internal DAC.
Body size is 69.2 (width) × 23.4 (height) in × 102.2 (depth) mm, weight about 250g. Built-in power supply lithium-ion rechargeable battery domestic (3.7V / 1,200mA), can be continuous playback of about 10 hours on a full charge.
Digital Audio format
"REX-KEB02AK" is equipped with the latest 2ch DAC "ES9018K2M" your ESS, portable headphone amplifier that achieves the full balance configuration circuit from input to output. S / PDIF and has developed a digital "Astell & Kern AK100" audio output capable iriver and is assumed to be utilized in combination with "Astell & Kern A120", is equipped with input terminals of two systems of optical digital input coaxial digital input . The corresponding up to 192kHz / 24bit for both optical digital / coaxial digital.
32bit Multi Thread processor and two independent X-Tal oscillator modules
(24.576MHz and 22.5792MHz) are included. The silicon and oscillators brings Low jitter
accurate Audio Master Clock to ES9018K2M DAC and brings clear sound.
Power & Volume Level
(1). Power & Volume Level
Power off : Turn Counter Clock wise to 7 O'clock position and check Click sound and
lighting off PW/LB LED.
Power on: Turn Clock wise from 7 O'clock position and check Click sound and lighting on
Volume level control: adjust Headphone output level to your favorite level.
(2). PW/LB LED.
Light on to indicate the operating state. Green light indicates Battery level is over 3.4V
and Red light indicates Low Battery state below 3.4V. In this case, charging is required.
(3). HP level Slide Switch
Select Headphone output level.
Right position shown in above brings High-Level for high impedance headphones.
Left position shown in above brings Low-Level for Low impedance headphones.
(4). Analog Filter selection Switch.
You can select Analog Filter Curve inside ES9018K2M DAC with this switch.
Right position brings Sharp Roll-Off Curve and Left position brings Slow Roll-off Curve.
(5). 3.5mm mini Jack.
Stereo analog audio output for headphones. Supports 8 Ohm to 300 Ohm impedance.
(6). 2.5mm micro jack ( L –BAL – R )
Analog Audio Balanced amp output to drive 4-wire ( 2 wire for L, 2wire for R) type
(1). Digital Audio Toslink Input
digital light: 24bit / 16bit, will be 192kHz ~ 44.1kHz.
(2). Digital Audio Coax Input.
digital coaxial: 24bit / 16bit, 192kHz ~ 44.1kHz
(3). DC+5V power input for charging.
USB micro-B Connector : Must connect DC+5V( +0.25V, -0.25V, 0.5A minimum )
Power supply unit to charge internal battery with USB-A to micro USB-B cable.
(4). Mode Select Slide Switch
Use this slide switch to change KEB02AK operation mode. This switch must be set in
Power_OFF state, Volume Knob at the front panel must be set at 7'Oclock position. And
the Volume Knob must be turned clockwise to enable operation mode being selected
by current setting of this switch for Optical or Coaxial Input
(1). Digital Audio:
24bit / 16bit, 192kHz ~ 44.1kHz
(2). Analog Audio output:
Single-end 3.5mm mini-jack x1(Stereo L,R). 1.62Vrms/68-Ohm x2
Balanced 2.5mm micro-jack x2 ( mono. L and R) 1.7Vrms/22-Ohm x2
(3). Battery Life:
5hr. Continues playing back music with 12'oclock Volume position with 8-ohm
Charging time: 3hr for full charge.
(4). External DC Power requirement:
DC +4.75V to 6.0V regulated 0.5A minimum.
Required charging cable with USB micro-B plug.
Note) KEB02iP does not supply charging power to iPod/iPhone/iPad.
(5). Size: 69.2(W) x 102.2(L) x 23.4(H) mm. 2.72"(W) x 4.02"(L) x 0.92"(H)
Excludes surface projection.
(6). Weight: 232 gram, 8.18 oz.
(7). Regulations : VCCI, FCC Class B, RoHs.