SAFETY WARNINGS AND GUIDELINES ....................................................................................................................................... 3
FEATURES .............................................................................................................................................................................................................. 4
CUSTOMER SERVICE .................................................................................................................................................................................... 5
Front Panel ..................................................................................................................................................................................................... 6
Analog RCA Input .................................................................................................................................................................................... 9
Digital Coaxial Input .............................................................................................................................................................................. 9
Digital Optical Input ............................................................................................................................................................................ 10
Digital AES/EBU Input ........................................................................................................................................................................ 10
Digital USB Input ..................................................................................................................................................................................... 11
Power ................................................................................................................................................................................................................ 11
Volume Control ....................................................................................................................................................................................... 12
MAIN MENU ...................................................................................................................................................................................................... 12
EQ MENU ............................................................................................................................................................................................................. 13
TECHNICAL SUPPORT .............................................................................................................................................................................. 22
SAFETY WARNINGS AND GUIDELINES
Please read this entire manual before using this device, paying extra attention to these
safety warnings and guidelines. Please keep this manual in a safe place for future reference.
This device is intended for indoor use only.
Do not expose this device to water or moisture of any kind. Do not place drinks or
other containers with moisture on or near the device. If moisture does get in or on
the device, immediately unplug it from the power outlet and allow it to fully dry
before reapplying power.
Do not touch the device, the power cord, or any other connected cables with wet
hands.
Do not subject the product to extreme force, shock, or fluctuations in temperature
or humidity.
Do not expose this device to excessively high temperatures. Do not place it in, on,
or near heat sources, such as a fireplace, stove, radiator, etc. Do not leave it in direct
sunlight.
Do not place or install this device in an area where it can be exposed to excessive
amounts of dust, humidity, oil, smoke, or combustible vapors.
Prior to operation, check the unit and power cord for physical damage. Do not use if
physical damage has occurred.
Before plugging the unit into a power outlet, ensure that the outlet provides the
same type and level of power required by the device.
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Unplug this device from the power source when not in use.
Take care to prevent damage to the power cord. Do not allow it to become
crimped, pinched, walked on, or become tangled with other cords. Ensure that the
power cord does not present a tripping hazard.
Never unplug the unit by pulling on the power cord. Always grasp the connector
head or adapter body.
Ensure that power is turned off and disconnected before making any electrical
connections.
Clean using a soft, dry cloth only. Do not use chemical cleaners, solvents, or
detergents. For stubborn deposits, moisten the cloth with warm water.
This device has no user serviceable parts. Do not attempt to open, service, or
modify this device.
FEATURES
Dual AK4493 32-bit Digital-to-Analog Converter with support for up to 768kHz PCM
and 22.4MHz DSD (Direct Stream Digital™)
Dual THX® AAA-788 amplifier modules with bipolar class-AB output stages, each
providing 1590mW of power into 16Ω at less than -140dB THD
Dirac Sensaround® provides a natural soundscape where listeners can enjoy their
favorite media in a way that seems to spread instruments, voices, and objects out
into space, enveloping the listener exactly as the artist intended
Six layer printed circuit board for the highest level of analog and digital signal
integrity
Highest quality NDK low noise, low jitter oscillators
Input options include USB, optical, coaxial, and AES/EBU digital audio inputs, as well
as two channels of balanced and unbalanced analog audio inputs
Outputs include unbalanced line level as well as balanced and unbalanced
headphone outputs
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CUSTOMER SERVICE
The Monoprice Customer Service department is dedicated to ensuring that your ordering,
purchasing, and delivery experience is second to none. If you have any problem with your
order, please give us an opportunity to make it right. You can contact a Monoprice
Customer Service representative through the Live Chat link on our website
www.monoprice.com during normal business hours (Mon-Fri: 5am-7pm PT, Sat-Sun: 9am-
6pm PT) or via email at support@monoprice.com
PACKAGE CONTENTS
Please take an inventory of the package contents to ensure you have all the items listed
below. If anything is missing or damaged, please contact Monoprice Customer Service for a
replacement.
1x Desktop headphone amplifier
1x AC power adapter
1x User's manual
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PRODUCT OVERVIEW
Front Panel
1. XLR Balanced Headphone Output
2. 1/4" (6.35mm) Unbalanced
Headphone Output
3. Display
Rear Panel
1. DC Power Jack
4. Menu Button
5. Value Knob
6. Enter Button
6. XLR Balanced Right Channel
2. USB Digital Audio Input
3. Optical Digital Audio Input
4. Coaxial Digital Audio Input
5. AES/EBU Digital Audio Input
Analog Audio Input
7. RCA Unbalanced Analog Audio
Input
8. RCA Pre-Amplifier Output
9. XLR Balanced Left Channel Analog
Audio Input
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Display
The Home Screen of the display shows the volume level in decibels (dB), the
selected input, and any selected options.
CONNECTIONS
Headphones Output
You can connect your headphones to the Desktop Headphone Amplifier using either an
unbalanced 1/4" (6.35mm) TRS plug or a balanced 4-pin XLR connector.
If your headphones use a 3.5mm TRS plug, you will need a 3.5mm-to-1/4" adapter,
such as the Monoprice 7139 adapter (available separately).
You cannot use both the balanced XLR and unbalanced 1/4" TRS headphone outputs
at the same time. When a 1/4" plug is inserted, the XLR output is muted.
When plugging or unplugging a 1/4" connector, completely insert or remove the
connector in one quick, smooth motion. Because of the design of the plug, keeping
the connector plugged in half way can cause a short circuit between the left and
right output channels and may trigger the short circuit protection feature.
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The following diagram shows the pin-out assignment for the Balanced Headphone
Output. Note that pins 2 (L-) and 4 (R-) are individual signal pins and cannot be tied
together as the ground pin for a single-ended headphone. Never use any adapter to
connect the Balanced Headphone Output to a single-ended headphone.
Pre-Amplifier Output
You can use the Desktop Headphone Amplifier as a pre-amplifier or a digital-to-analog
converter (DAC) by connecting the RCA Pre-Amplifier Output to a power amplifier or a pair
of powered speakers.
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Analog RCA Input
You can connect an analog audio source device to the RCA Unbalanced Analog Audio
Input using a pair of RCA cables (available separately).
Digital Coaxial Input
You can connect a digital audio source device to the Coaxial Digital Audio Input using a
digital coaxial cable (available separately). The digital signal will be converted by the
internal DAC and sent to the analog headphone and pre-amplifier outputs.
The Coaxial Digital Audio Input accepts only stereo PCM signals. Compressed and
multichannel audio signals, such as Dolby Digital™ and DTS®, are not supported.
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Digital Optical Input
You can connect a digital audio source device to the Optical Digital Audio Input using an
optical cable, also known as a TOSLINK® cable (available separately). The digital signal will
be converted by the internal DAC and sent to the analog headphone and pre-amplifier
outputs.
The Optical Digital Audio Input accepts only stereo PCM signals. Compressed and
multichannel audio signals, such as Dolby Digital™ and DTS®, are not supported.
Digital AES/EBU Input
You can connect a device with an AES/EBU digital output to the AES/EBU Digital Audio
Input using a 3-pin XLR cable (available separately). The digital signal will be converted by
the internal DAC and sent to the analog headphone and pre-amplifier outputs.
The AES/EBU Digital Audio Input accepts only stereo PCM signals. Compressed and
multichannel audio signals, such as Dolby Digital™ and DTS®, are not supported.
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Digital USB Input
You can connect your computer to the Desktop Headphone Amplifier using a USB cable
with a Type-A connector on one end and a Type-B on the other end (available separately).
This allows you to use your computer and any playback software you prefer to output
audio through the amp. The digital signal will be converted by the internal DAC and sent to
the analog headphone and pre-amplifier outputs.
OPERATION
Power
Momentarily press the Menu Button on the front panel to turn the amplifier on.
While the unit is powering on, the Monolith™ logo will display. When it is fully ready
for use, the Home Screen will display.
Press and hold the Menu Button until the display scrolls off to turn the amplifier off.
Source Selection
Perform the following steps to select the input source.
1. Press and hold the Enter Button for several seconds.
2. Use the Value Knob to scroll backwards or forwards through the input options. The
Display will show the currently selected input.
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3. Once the desired input is displayed, momentarily press the Enter Button to select it.
The Display will revert back to the Home Screen with the selected input visible in
the top right corner.
The input options include RCA LINE, XLR LINE, OPTICAL, COAXIAL, AES3, and
USB.
Volume Control
Rotate the Value Knob clockwise or counterclockwise to increase or decrease the
volume level. The Display will change to show volume level in decibels (dB).
The numeric dB value indicates the amount of attenuation (negative) or gain
(positive) applied to the original input signal.
The volume level range is -80.0dB to +16.0dB, in 0.5dB increments.
It is normal for the displayed dB value to change by several dB when adjusting the
volume at the low end of the range due to the logarithmic nature of the volume
control curve.
MAIN MENU
Momentarily press the Menu Button to display the Main Menu.
Rotate the Value Knob clockwise or counterclockwise to cycle forward or backward
through the list of available menus.
Momentarily press the Enter Button to select the displayed menu.
Momentarily press the Menu Button to return to the Main Menu.
The submenus are EQ [1/4], DRC [2/4], DIRAC [3/4], and SETTINGS [4/4].
After about 30 seconds of no input while any menu or submenu is displayed, the
Display will revert back to the Home Screen.
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EQ MENU
The EQ Menu allows you to set the parameters for the Shelf EQ and up to five Parametric
EQs (PEQs).
Shelf EQ
The Shelf EQ is the equivalent of the Bass and Treble controls on a conventional amplifier,
but with more control over the amount of gain and the specific frequencies. The LF GAIN
value applies to all frequencies below the selected frequency, while the HF GAIN value
applies to all frequencies above the selected frequency.
Perform the following steps to set the Shelf EQ.
1. Momentarily press the Menu Button. The Display will show EQ [1/4].
2. Momentarily press the Enter Button. The Display will show SHELF EQ [1/6].
3. Momentarily press the Enter Button. The Display will show SHELF EQ [1/4] with a
pointer to the left of the LF GAIN label.
4. Rotate the Value Knob clockwise or counterclockwise to increase or decrease the
LF GAIN value from -6dB to +6dB in 0.5dB increments.
5. Momentarily press the Enter Button. The Display will change to show SHELF EQ
[2/4] and the pointer will move to the left of the FREQ label.
6. Rotate the Value Knob clockwise or counterclockwise to increase or decrease the
FREQ value from 60Hz to 200Hz in 10Hz increments.
7. Momentarily press the Enter Button. The Display will change to show SHELF EQ
[3/4] and the pointer will move to the left of the HF GAIN label.
8. Rotate the Value Knob clockwise or counterclockwise to increase or decrease the
HF GAIN value from -6dB to +6dB in 0.5dB increments.
9. Momentarily press the Enter Button. The Display will change to show SHELF EQ
[4/4] and the pointer will move to the left of the FREQ label.
10. Rotate the Value Knob clockwise or counterclockwise to increase or decrease the
FREQ value from 5kHz to 12kHz in 1kHz increments.
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11. Momentarily press the Enter Button. The Display will cycle back to show SHELF EQ
[1/4] with the pointer to the left of the LF GAIN label.
12. Momentarily press the Menu Button three times to return to the Home Screen.
Alternatively, wait about 30 seconds and the Display will automatically return to the
Home Screen. The Home Screen will display an EQ label, indicating that EQ is
enabled.
Note: Once a value is changed in any of the above steps, it will take effect whether or not
the
Enter Button
is pressed. There is no Cancel function to abort changes that have been
made.
PEQ
The Desktop Headphone Amplifier features five Parametric EQs (PEQs), which you can use
to boost or cut frequencies with more precision than the Shelf EQ offers. Rather than
boosting or cutting all frequencies above or below a particular point, you can boost or cut
a specific range of frequencies within a bell curve.
This gives a greater amount of boost or cut to the frequency at the center of the curve and
a smaller amount to frequencies the further they get from the central frequency. This
allows you to accentuate particular sounds, voices, or instruments in an audio mix. It is also
useful if the speakers or headphones or even any item within the room have a resonant
frequency that rattles.
With PEQ you can set which frequency is at the apex of the curve, the amount of gain or
attenuation, and the width of the curve.
Perform the following steps to set one of the five available PEQs.
1. Momentarily press the Menu Button. The Display will show EQ [1/4].
2. Momentarily press the Enter Button. The Display will show SHELF EQ [1/6].
3. Rotate the Value Knob clockwise until the Display shows PEQ 1 [2/6].
4. Momentarily press the Enter Button. The Display will show PEQ 1 [1/4] with a pointer
to the left ENABLE label.
5. Rotate the Value Knob clockwise until the value for ENABLE is ON.
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6. Momentarily press the Enter Button. The Display will show PEQ 1 [2/4] with the
pointer to the left of the FREQ label.
7. Rotate the Value Knob clockwise or counterclockwise to increase or decrease the
FREQ value in the range 50Hz to 15kHz. The FREQ value can be adjusted in 1Hz