Audeze THE KING, Руководство пользователя, Страница: 7 / 16

Introduction
The King Headphone Amplifier was designed for Audeze by
world-renowned circuit designer Bascom King. His long experience
dates back to a time when tubes ruled the amplifier world. That,
along with advances in solid-state technology, led to The King’s
unique combination of both.
The King is a class-A hybrid design featuring E88CC triode tube
inputs driving MOSFET output devices. The tube section is a
differential stage that’s directly coupled to the MOSFET drivers. A
current source ensures proper tube bias and improves their
linearity. A DC servo circuit is in the loop between the input and
output stage to keep DC offset as close to zero as possible
(typically less than 5mV.)
Output devices are matched IRFZ20 MOSFETs chosen for their
linearity and reliability. A symmetrical regulated power supply
delivers ±16V DC to the output devices and there are no capacitors
in the signal path. This results in a virtually flat frequency response
throughout the range of our Audio Precision APX 525 audio
analyzer: -0.1dB at 1Hz to 80kHz.
Left and right channels are on separate PCBs and each has its own
voltage regulators to reduce crosstalk between channels. Each PCB
features a protective shield of perforated, powder-coated magnetic
material.
The toroidal transformer is massively oversized, molded in epoxy
and shielded to further improve signal-to-noise ratio. The main
power supply and protection PCBs also feature shields of perforated
powder-coated magnetic material.
A microprocessor provides overload protection. Voltage across a
1 ohm resistor connected to the source of the output MOSFETs is
constantly monitored. The relay connecting the output to the
headphone is powered off if it becomes higher than a predeter -
mined value. The same relay disconnects the output until the servo
eliminates DC offset as the amplifier powers on.
Headphone impedance connected to the output is checked during
the initial power-on delay. If the impedance is lower than 10 ohms
the microprocessor won’t activate the relay. We recommend that
you leave your headphone connected during power-on as The King
checks for potential cable shorts.
There are two red and green LEDs that indicate the status of the
output relays on both channels. During the initial power-on phase
the red LEDs are on and that can be seen through holes in the top
cover. After the relays connect the output to the headphone the red
LEDs extinguish and green LEDs are lit.
The LED SPL Meter on the front panel indicates actual SPLs (Sound
Pressure Levels) delivered by the LCD-4 on both channels. A
removable calibrated display for other Audeze headphones will be
offered at a later date.
The King delivers a full 6 watts at 20 ohms and will drive any
headphone with ease.
Product Registration
Register your Audeze The King Headphone Amplifier at
www.audeze.com for information, updates and news.
Safety Guide
Be sure to turn off The King Headphone Amplifier before connecting
or removing audio or power cables. Lower the volume before
connecting or removing your headphone cable, then gradually
increase the volume until you reach a comfortable level.
The King’s hybrid tube/MOSFET design generates heat so we
recommend leaving at least a 1-inch clearance around the chassis for
proper heat dissipation. Keep in mind that listening to music for long
periods of time at excessive levels can cause irreparable damage to
your ears.
AC Power
Ensure the voltage indicated on the rear panel of The King matches
your AC mains supply. Attempting to use The King at any voltage
other than that selected on the rear panel may cause damage not
covered by the Warranty.
Safety Features
Microprocessor-controlled safety features abound and are not in the
signal path. These include a soft-start timer delay, overcurrent and
short-circuit protection, and relays connecting the amplifier’s output
to the headphone. The output impedance is checked during the
initial power-on phase to avoid any output if the impedance is below
preset limits.