Audeze The king User manual

www.audeze.com

ACC1018

THE KING GUIDE

Thank you for purchasing Audeze's The King Headphone

Ampliﬁer. You are now a proud owner of one of the best

headphone ampliﬁers that we highly recommend with all of

our products, especially the recently released LCD-4. Together

they will bring you the best sound that Audeze has to offer.

To get the most out of your purchase, please take the time to

carefully read through this user guide and warranty.

THE KING

HEADPHONE AMPLIFIER

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.

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.

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

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.

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.

Care and Maintenance

Regular maintenance is not required, but an occasional wipe with a

clean, dry, lint-free cloth is recommended while The King is powered

down.

Tube Replacement: The two matched E88CC tubes are long-life,

shock and vibration resistant, and can last up to 10,000 hours.

Compatible replacements include 6DJ8 and variants including 6922,

7308, 7DJ8, ECC88 and 6H23. To change the input tubes ﬁrst switch

off the power, remove the power cable for safety, and remove The

King’s top cover. Gently pull the tubes from their sockets and replace

using the cotton gloves supplied. Replace the top cover, reconnect

the power cable and power on.

The heaters for both tubes are connected in series; if one of them is

defective the other will not function.

WARNING: Do not use any tube types other than those indicated

above. Doing so will void the warranty.

TIP: If you leave your cables connected to The King for long periods

of time, Audeze recommends that every six months you power down

The King and disconnect and reconnect the cables several times; the

wiping action cleans the RCA terminals of oxidation.

NOTE: Keep the product, accessories and packaging out of the reach

of children.

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.

Real-Time Metering

The front panel LED SPL meters are calibrated to show actual SPLs when

used with the LCD-4. The 75-segment LEDs display true SPLs from 90dB to

120dB. The last red LED segment warns of SPLs greater than 120dB. You

should NEVER see this red LED if you value your hearing!

1. Quarter-Inch TRS Headphone Connectors - Two output connectors allows

sharing your music or comparing two headphones.

2. Overload Protection – A red LED indicates that an overload condition has

occurred; the output relay will disconnect the headphone as long as the

problem persists.

3. Low Impedance (Short) – A yellow LED indicates that the connected

headphone impedance is lower than 10 ohms; the output relay will not

activate with this load.

4. LED SPL Meter - Two rows of green LEDs show momentary SPL levels on

the LCD-4; peak level follows current level with a slight hold. The scale is

held in place with magnets and is removable.

5. Volume Control

Connecting the King Headphone Ampliﬁer

Connect the left and right source component output cables to the left

and right RCA or XLR analog inputs on the back of The King. XLR inputs

are provided for balanced devices but The King is internally wired for

single-ended operation and only the positive XLR input is active. The

negative XLR input is terminated to ground through a 22k ohm resistor.

Connect the AC power cord, and then your headphone to the standard

quarter-inch stereo output connector on the front panel. Be sure to keep

the volume low on ﬁrst listen.

THE KING

MIN MAX

123 54

FRONT PANEL

Real-Time Metering

The front panel LED SPL meters are calibrated to show actual SPLs when

used with the LCD-4. The 75-segment LEDs display true SPLs from 90dB to

120dB. The last red LED segment warns of SPLs greater than 120dB. You

should NEVER see this red LED if you value your hearing!

1. 3-Pin XLR Connectors - XLR inputs are provided for balanced devices but

The King is wired for single-ended operation.

2. RCA Connectors - Main inputs, runs parallel to the XLR connectors.

3. Voltage Selector – Changes mains voltage from 110-120V AC to

220-240V AC depending on local line voltage.

4. Power Input – Standard three-prong IEC connector with line ﬁlter and fuse

drawer. For 110V use 1.6A slow blow fuse, for 220V use 1A slow blow fuse.

Connecting the King Headphone Ampliﬁer

Connect the left and right source component output cables to the left

and right RCA or XLR analog inputs on the back of The King. XLR inputs

are provided for balanced devices but The King is internally wired for

single-ended operation and only the positive XLR input is active. The

negative XLR input is terminated to ground through a 22k ohm resistor.

Connect the AC power cord, and then your headphone to the standard

quarter-inch stereo output connector on the front panel. Be sure to keep

the volume low on ﬁrst listen.

INPUTS INPUTS

BALANCED UNBALANCED

110 - 120 VAC, 50-60 Hz

220 - 240 VAC, 50-60 Hz

- L -

- R -

VOLTAGE

SELECTOR

POWER

CONSUMPTION

30W MAX

MADE IN CALIFORNIA, USA

THE KING

HIGH RESOLUTION HEADPHONE AMPLIFIER

A-CLASS TUBE / MOSFET SINGLE-ENDED DESIGN

SERIAL NUMBER

CAUTION RISK OF ELECTRIC SHOCK

NO USER SERVICEABLE PARTS INSIDE

341 2

REAR PANEL

Speciﬁcations

Type ..........................................Class-A hybrid, tube input, MOSFET drivers and output

Tube Complement ................. Stock: E88CC, matched pair

Compatible: 6922, 6DJ8, 6H23, 7308, 7DJ8, ECC88

Output Power ......................... 6W into 20 ohms

Frequency Response .............10 Hz-100 kHz, -0.1dB

Total Harmonic Distortion .... < 0.1%, 20 Hz-20 kHz at full output

SNR .......................................... 120dB, A-weighted

Output Impedance ................ 0.3 ohms

Input Impedance ....................10k ohms

Power requirements .............. 110-120V AC, 50/60Hz, 220-240V AC, 50/60Hz,

externally switchable

Fuse .......................................... 1.6A slow blow for 110-120V AC,

1A slow blow for 220-240V AC

Power Consumption ............. 30W maximum

Weight ..................................... 20lbs/9Kg

Package Includes

• Audeze The King Headphone Ampliﬁer

• User Guide and warranty

• Certiﬁcate of authenticity

• 6-ft AC power cord

• 1 Allen key for top cover

• 1 Pair of cotton gloves

Unpacking

Take care handling The King when

unpacking and placing it in your

system. Be aware of the weight

(20lbs/9Kg) when choosing an

appropriate location for it. Be sure

to check if the package arrives

undamaged with everything safely

packed.

Symptom Solution

No lights 1. Check that power cable is connected to working AC outlet.

2. Check the fuse.

3. If both are OK, contact Audeze support.

No sound 1. Check signal source connection.

2. Check headphone and cable.

3. Check to see faint red glow in tubes; if you can’t see the glow

one of the tubes is defective or heater power is missing.

4. If everything above is OK contact Audeze support.

Red light visible 1. Normal for ﬁrst 75 seconds after power-on.

through the top cover 2. If yellow LED on Front Panel is lit, impedance lower than

10 ohms is connected. Disconnect headphone cable,

yellow LED should be off and after maximum 75 seconds

red light should turn to green.

3. If red light continues after that contact Audeze support.

Red LED on front 1. Reduce volume until red LED is off.

panel is on 2. If reducing volume doesn’t help, contact Audeze support.

Yellow LED on front This occurs only during initial power-on phase, if it persists:

switching on 1. Disconnect headphone and check the cable, there might be

a short or the impedance of the headphone is below 10 ohms.

2. If both cable and headphones are OK, contact Audeze.

Volume is low even 1. Check your signal source.

at maximum or 2. Check your tubes for faint glow.

distorted sound 3. Check your tubes on tube tester if possible, they may have

reached the end of their life cycle when the cathode is

depleted (emission <50%).

4. If all above OK, contact Audeze support.

Troubleshooting

Warranty

The Audeze product comprising The King Headphone Ampliﬁer (an “Audeze

Product”) is under warranty for three (3) years from the date of original retail

purchase (the “Warranty Period”).

Warranty on tubes is limited to 90 days and excludes physical damage other than

from shipping. Note that shipping damage claims must be made within one week.

What’s covered: Audeze warrants to the original purchaser that the Audeze Product

will be free of defects related to manufacturing, parts, materials, and workmanship

under normal and accepted use in accordance with Audeze’s published guidelines.

Audeze’s guidelines include, but are not limited to, information contained in

technical speciﬁcations, user manuals and service communications.

What’s not covered: This warranty does not cover defects resulting from improper

or unreasonable use or maintenance; cosmetic damage, including but not limited to

scratches, dents and broken parts; failure to follow operating instructions; accident;

excess moisture; excess temperature; power surges; connections to improper

voltage supply; unauthorized alteration or modiﬁcation of original condition; damage

caused by use with non-Audeze products; products purchased from unauthorized

dealers; or defects incurred during transportation for which claims must be

presented to the carrier.

What we will do: We will, at our sole discretion and to the extent permitted by law,

repair or replace (using new or refurbished Audeze Parts) Audeze Products that are

under warranty for the period listed, from the date of original retail purchase.

What we will not do: Except as stated below, pay shipping, insurance or transporta-

tion charges from you to us, or any import fees, duties and taxes. If the Audeze

Product is covered by this warranty and is provided to us within the ﬁrst 30 days of

the Warranty Period, then we will reimburse you for shipping charges.

If the Audeze Product you send to us is not covered by this warranty, you will be

charged the shipping costs. If you are outside the USA and purchased this product

directly from Audeze you must claim your warranty service from Audeze, not from a

foreign dealer or distributor.

Warranty eligibility statement: To be eligible for service under this warranty you must

include with the repair item(s) a valid bill of sale from an authorized Audeze retailer

detailing the following information:

Retailer’s name

Original date and proof of purchase

Model or SKU number of the product purchased

Serial Number

Additional product information and limitations

Warranty replacements: Audeze strives to improve the performance of our products,

and therefore reserves the right to make changes to our design/speciﬁcations/materi-

als at any time without notiﬁcation. Audeze may, at its discretion, choose to replace

the Audeze Product completely with a new or remanufactured product. In the event of

product obsolescence, a suitable replacement will be chosen based upon the features,

the intended use (as determined by Audeze) and the retail price of the original Audeze

Product.

Product: All warranty replacements are guaranteed for 90 days or until the conclusion

of the Warranty Period of the original Audeze Product, whichever period is greater.

Audeze does not provide advance replacements for Audeze Products.

Determining authority: Audeze will be the ﬁnal determining authority for all potential

warranty claims for service and/or replacement. How to claim warranty service:

A) If you reside in the United States and purchased direct from Audeze.com

email Support@Audeze.com.

B) If you reside in the United States and purchased from an authorized Audeze

dealer contact your dealer or Support@Audeze.com.

C) If you are an international customer who has purchased through your local

dealer contact your local dealer or distributor for warranty service.

D) If you are an international customer who purchased direct from Audeze.com

you must contact Audeze at Support@audeze.com for service and support.

Any shipment back to Audeze for repair will be at the expense of the customer.

You will need your serial number and proof of purchase to complete any RMA process.

Other conditions/rights: EXCEPT AS PROVIDED IN THIS WARRANTY AND TO

THE MAXIMUM EXTENT PERMITTED BY LAW, AUDEZE IS NOT RESPONSIBLE

FOR DIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING

FROM ANY BREACH OF WARRANTY OR CONDITION, OR UNDER ANY OTHER

LEGAL THEORY, INCLUDING BUT NOT LIMITED TO LOSS OF USE; LOSS OF

REVENUE; LOSS OF ACTUAL OR ANTICIPATED PROFITS; LOSS OF GOODWILL;

LOSS OF, DAMAGE TO, COMPROMISE OR CORRUPTION OF DATA; OR ANY

INDIRECT OR CONSEQUENTIAL LOSS OR DAMAGE HOWSOEVER CAUSED

INCLUDING THE REPLACEMENT OF EQUIPMENT AND PROPERTY.

THE FOREGOING LIMITATION SHALL NOT APPLY TO DEATH OR PERSONAL

INJURY CLAIMS, OR ANY STATUTORY LIABILITY FOR INTENTIONAL AND GROSS

NEGLIGENT ACTS AND/OR OMISSIONS. SOME STATES IN THE USA OR OTHER

COUNTRIES. DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL

OR CONSEQUENTIAL DAMAGES, SO THE ABOVE LIMITATION OR EXCLUSION

MAY NOT APPLY TO YOU.

TO THE EXTENT PERMITTED BY LAW, THIS WARRANTY AND THE REMEDIES SET

FORTH ARE EXCLUSIVE AND IN LIEU OF ALL OTHER WARRANTIES, REMEDIES

AND CONDITIONS, WHETHER ORAL, WRITTEN, STATUTORY, EXPRESS OR

IMPLIED. AUDEZE DISCLAIMS ALL STATUTORY AND IMPLIED WARRANTIES,

INCLUDING WITHOUT LIMITATION, WARRANTIES OF MERCHANTABILITY AND

FITNESS FOR A PARTICULAR PURPOSE AND WARRANTIES AGAINST HIDDEN OR

LATENT DEFECTS, TO THE EXTENT PERMITTED BY LAW. IN SO FAR AS SUCH

WARRANTIES CANNOT BE DISCLAIMED, AUDEZE LIMITS THE DURATION AND

REMEDIES OF SUCH WARRANTIES TO THE DURATION OF THIS EXPRESS

WARRANTY AND, AT AUDEZE'S OPTION, THE REPAIR OR REPLACEMENT

SERVICES DESCRIBED HEREIN. SOME STATES (INCLUDING COUNTRIES AND

PROVINCES) DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED

WARRANTY (OR CONDITION) MAY LAST, SO THE LIMITATION DESCRIBED ABOVE

MAY NOT APPLY TO YOU.

Audeze LLC

http://support.audeze.com