monolith Alex Cavalli Liquid Gold X User manual

Liquid Gold X Balanced Headphone Amplifier and DAC
by Alex Cavalli
P/N 38967
User's Manual

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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 expose this device to excessive vibration.
•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 a heat
source, such as a fireplace, stove, radiator, etc. Do not
leave it in direct sunlight.
•This device ventilates excessive heat through the slots
and mesh openings in the case. Do not block or cover
these openings. Ensure that the device is in an open

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area where it can get sufficient airflow to keep from
overheating.
•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.
•Use only in a well-ventilated area. Do not use in close,
confined spaces.
•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.
•Do not use any AC power adapter other than the one
provided with the unit. The adapter is closely matched
with the MCU to provide the proper high current influx
when power is applied. Use of aftermarket power
adapters is likely to damage the amplifier.
•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

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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.

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INTRODUCTION
The Monolith™Liquid Gold X Balanced Headphone Amplifier
and DAC by Alex Cavalli is a fully differential, balanced, solid
state amplifier. It is a miniaturized version of Cavalli Audio's
high-end Liquid Gold amplifier. The Monolith Liquid Gold X
amplifier circuit topology and component values are identical
to the original Cavalli Liquid Gold. It features a balanced 4-pin
XLR output and an unbalanced 1/4" TRS output. The TRS output
is provided for compatibility with TRS terminated headphones,
but it is recommended to use the amp in fully balanced mode
using balanced headphones.
The amp has both balanced XLR and unbalanced (RCA) inputs.
The unbalanced input has an internal, solid state buffered phase
splitter to create a balanced signal and drive the amp fully
balanced. The Monolith Liquid Gold X amplifier includes its own
built-in, fully balanced DAC with USB, Coaxial, and Optical
inputs. The amplifier has 4x and 6x gain settings and an
approximate full output power of 3.6 watts per channel with a
50-ohm load.

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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
or via email at [e-mail]. Check the website for
support times and links.
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 Monolith™ Liquid Gold X Amplifier and DAC
1x AC Power Adapter
1x User's Manual

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PRODUCT OVERVIEW
Front Panel
1. POWER: Momentarily press the button to signal the
MCU to turn the amplifier on or off.
2. SE: Unbalanced TRS headphone output.
3. B: Balanced 4-pin XLR headphone output.
4. STATUS LED: The LED illuminates or blinks red and/or
white to indicate a normal operating or fault condition.
Refer to the table in the BLINK CODES section for
details.
5. GAIN: This toggle button determines the amount of
gain to apply to the signal. When the button is IN, the
gain is 6x and when it is OUT the gain is 4x.
6. VOLUME: Turn the knob clockwise to increase the
volume level and counterclockwise to decrease the
volume level.

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7. DAC SELECT: Momentarily press the button to cycle
through the DAC inputs. When power is first
connected, it defaults to the USB input. The cycle order
is USB, Coaxial, and Optical, then back to USB.
8. INPUT SELECT: Momentarily press the button to cycle
through the inputs. When power is first connected, the
input defaults to the balanced XLR input. The cycle
order is Balanced XLR, Unbalanced RCA, and DAC, then
back to Balanced XLR.
9. DAC LEDs: The three LEDs indicate which DAC input is
selected. From top to bottom, they indicate USB,
Coaxial, and Optical.
10. INPUT LEDs: The three LEDs indicate which input is
selected. From top to bottom, they indicate DAC,
Balanced XLR, and Unbalanced RCA.

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Rear Panel
11. BAL: Balanced XLR inputs.
12. SE: Unbalanced RCA inputs.
13. USB: USB digital audio DAC input.
14. COAX: Coaxial digital audio DAC input.
15. OPTICAL: Optical digital audio DAC input.
16. AUTO/OFF: This switch enables or disables the auto-off
feature.
17. POWER: DC barrel connector for connecting the
included AC power adapter.

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BLINK CODES
CONDITION
STATUS LED
Normal Power Off
Blinks red (0.5 sec on, 0.5 sec
off) 5 times
Ground Failure
Blinks white (0.1 sec on, 0.1
sec off) 75 times
DC Offset Failure
Blinks red (0.1 sec on, 0.1 sec
off) 75 times
EU Shutdown Final Minute
Blinks white (1 sec on, 1 sec
off) 30 times
DC Module Wrong Voltage
Blinks red and white
alternately (1 sec on, 1 sec
off) 8 times
Firmware Unknown State
Blinks red and white
alternately (3 sec on, 3 sec
off) 5 time

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MICROCONTROLLER UNIT (MCU)
INTELLIGENCE
The built-in MCU controls all of the amplifier's operational
behaviors. It turns the amplifier on and off, monitors various DC
voltages for acceptable values, detects bad ground and output
DC offset conditions, performs various timings, manages input
and DAC selectors, manages EU auto shutdown, and shows
various normal and error/fault conditions. The red/white
STATUS LED on the front panel is used to indicate these
conditions with various colors and blink rates. Refer to the
BLINK CODES section for details. Please review this section
before attempting to operate the Monolith™ Liquid Gold X
amplifier.
DC Plug-In Delay
The Monolith™ Liquid Gold X amplifier has several built-in
delays to ensure that all DC voltages are in their proper ranges
before allowing you to power up and connect headphones.
The first important delay is immediately after plugging in DC
power. The MCU waits 3 seconds before measuring the DC
voltage of the power source. If this source is not within range
the MCU will show a blink code using the STATUS LED on the
front panel. You will not be able to power on the amp until the

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MCU determines that the DC source is within acceptable range.
Pushing the power button will only cause the LED blink cycle to
be repeated.
If the DC power is detected out of range, unplug the AC power
adapter for 30 seconds, then plug it back in to reset the MCU.
If no blink code is shown after 3 seconds, press and release the
POWER button. The STATUS LED will illuminate red and the
three INPUT LEDs will illuminate, indicating that the amplifier is
ready for operation.
Ground Test Delay
The MCU will wait for about 3 seconds and then measure all of
the important internal ground relationships. If these are not
within acceptable range, the MCU will power down the amp
and show a ground failure blink code. If this failure occurs
mulitiple times, please contact Monoprice™Technical Support
for assistance.
DC Offset Delay
If the ground connections are acceptable, the MCU will wait
about 15 seconds while the amp finishes powering on. After 15
seconds the MCU will measure the DC offsets at the headphone
outputs. If these are acceptable, it will connect the headphones

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(relay click) and the STATUS LED will change from red to white.
If the DC offset is not acceptable the MCU will power down the
amp and show an offset failure. If the amp consistently shuts
down during power up due to offset failure, please contact
Monoprice™Technical Support.
Notes:
•You can change the selected input and selected DAC
source while the amp is powering on.
•We recommend setting the volume level to minimum
during power on.
•After the STATUS LED changes from red to white and
the headphones are connected, all normal amp
features should be operational.
EU Compliant Auto Shutdown
To comply with EU Regulation (EC) No. 1275/2008, this amplifier
features an auto-off function, which is enabled or disabled
using the AUTO/OFF switch on the rear panel. When the switch
is placed in the OFF position, there is no effect on the
amplifier's operation. When the AUTO/OFF switch is placed in
the AUTO position, the MCU monitors the selected input for a
valid audio signal.

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If the input signal falls below a very low threshold continuously
for 4 hours, the MCU will power down the amp to save
electricity. If an audio signal is detected at any time, the timer
will reset. If the AUTO/OFF switch is set to the OFF position
during the countdown, the timer will reset. During the last
minute before automatic shutdown, the STATUS LED will show
a blink code. If the power button is pressed while this blink
code is displayed, the timer will reset.
DC Offset or Ground Fault
if the MCU detects either of these two conditions during
operation, it will disconnect the headphones and the STATUS
LED will change from white to red. If either condition is an
extreme failure, the MCU will also shut down the amplifier with
the associated blink code. If the either condition is deemed
abnormal, but not extreme, the MCU will attempt to recover
normal operation. If the MCU recovers, it will reconnect
headphones and change the STATUS LED red to white. If it
cannot recover after a determined period of time, it will shut
down the amplifier with the associated blink code.

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Firmware Enters Unknown State
In the event a critical failure occurs and the firmware enters an
unknown condition, it will power down the amp and indicate
this condition with a specific blink code. Unplug the AC power
adapter for 30 seconds, then plug it back in to reset the MCU. If
this condition persists, please contact Monoprice™ Technical
Support for assistance.
OPERATING GUIDELINES
To get the most out of your amplifier and to protect it from
possible damage, follow the guidelines listed below.
Gain Setting
While the amplifier supports hot switching the gain setting,
changing gain introduces a small DC transient at the output.
Depending on the sensitivity of your headphones, this transient
might be quite loud or damaging. We highly recommended that
you turn off the amplifier before changing the gain setting.

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Connecting Headphones While Audio is Playing
Under many conditions, if you plug or unplug your headphones
while the amp is delivering power, you will trip the output
offset detector. This is the MCU protecting the amp from
damage. This condition is likely to occur more frequently when
using the TRS output because of the output shorting that
occurs when the TRS plug is inserted into the jack. For best
results and the safest operation, turn the amplifier off before
plugging or unplugging your headphones.
Electrical Connections
You should power down the amplifier and unplug it from the
power source before making any electrical connections,
including the inputs and the headphone outputs. This ensures
that no transient voltage spike can occur, which can cause
damage to the amplifier and/or other equipment.
Volume
For best results, set the volume control to the minimum level
before starting audio playback, then increase volume to a
comfortable listening level.

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Amplifier Break-In
Most amplifiers need at least 100 hours of continuous music
playback to reach their full sound signature. It is not necessary
to set up a break-in period. The amp will change character as
you listen normally and you will hear it evolve into its natural
sound signature. If you do employ a break-in period, we
recommend about 100 hours of continuous music playing with
no headphones connected and the volume set to about 10
o'clock.
Constant On
Other than the aforementioned break-in period, the amplifier
should be powered down when not in use to ensure the
longest possible life for the components.
Balanced vs. Unbalanced
To get the best performance from your amplifier, use the
balanced headphone output, as well as the balanced XLR
inputs. The amp is designed to run with a balanced input and
output. If you only have TRS terminated headphones, we
recommend that you find a way to listen with balanced
headphones before making any judgement on the performance

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of the amp. Remember that the unbalanced output is provided
for convenience only.
Power Source
This amplifier is supplied with a universal AC power adapter,
which can operate with voltages from 100 ~ 240 VAC, 50/60 Hz.
It has a NEMA® 1-15 plug for use with standard US AC outlets,
but will work with a physical adapter suitable for your location.
Aftermarket AC Power Adapters
The AC power adapter is matched to the onboard power
control circuit. A particular feature of this matching is to control
the high current influx when DC power is plugged in and when
the amp is turned on. Therefore, DO NOT USE AFTERMARKET
LINEAR SUPPLIES AS THEY ARE VERY LIKELY TO DAMAGE YOUR
AMPLIFIER.
Grounding
This amplifier shares the ground of the source it is plugged into.
In unusual circumstances, ground noise may occur, depending
on the exact grounding of the source equipment.

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TECHNICAL SUPPORT
Monoprice is pleased to provide free, live, online technical
support to assist you with any questions you may have about
installation, setup, troubleshooting, or product
recommendations. If you ever need assistance with your new
product, please come online to talk to one of our friendly and
knowledgeable Tech Support Associates. Technical support is
available through the online chat button on our website
www.monoprice.com or through email by sending a message to
[e-mail]. Check the website for support times and
links.
SPECIFICATIONS
General
Model
38967
Frequency Response
5 Hz ~ 60 kHz ±0.05dB
Maximum Output Balanced
(voltage for ≈ 1% THD)
Watts
Vrms
33 Ohms
6.223
14.33
56 Ohms
3.927
14.83
150 Ohms
1.589
15.44

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300 Ohms
0.820
15.68
Maximum Output Single
Ended (voltage for ≈ 1% THD)
Watts
Vrms
33 Ohms
1.769
7.64
56 Ohms
1.109
7.88
150 Ohms
0.448
8.20
300 Ohms
0.231
8.32
Crosstalk (@1kHz 1 Vrms
input unit gain balanced
in/out)
-88dB
Channel Balance (with pot at
unit gain balanced out)
0.1dB
Input Power
36 VDC, 1.4A
AC Adapter Input Power
100 ~ 240 VAC, 50/60 Hz
Dimensions
8.7" x 8.5" x 2.0"
(222 x 216 x 51 mm)
Weight
3.3 lbs. (1.5 kg)