Monoprice 27222 User manual

MONOPRICE
Pure Tube Stereo Amplifier
with Bluetooth, Line-in, and Phono Inputs
PID 27222
User's Manual

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CONTENTS
SAFETY WARNINGS AND GUIDELINES.............................................................................................................................................................. 3
INTRODUCTION.......................................................................................................................................................................................................................5
FEATURES.....................................................................................................................................................................................................................................5
CUSTOMER SERVICE...........................................................................................................................................................................................................6
PACKAGE CONTENTS........................................................................................................................................................................................................6
CONTROLS AND CONNECTIONS............................................................................................................................................................................. 7
Front Panel........................................................................................................................................................................................................................... 7
Rear Panel.............................................................................................................................................................................................................................. 7
CABLE PREPARATION........................................................................................................................................................................................................8
Speaker Wires....................................................................................................................................................................................................................8
RCA Cables...........................................................................................................................................................................................................................9
SETUP...............................................................................................................................................................................................................................................9
Tubes .........................................................................................................................................................................................................................................9
Speaker Connections................................................................................................................................................................................................10
Source and Power Connections...................................................................................................................................................................... 11
Bluetooth Connection.............................................................................................................................................................................................12
MAINTENANCE...................................................................................................................................................................................................................... 12
TECHNICAL SUPPORT......................................................................................................................................................................................................12
SPECIFICATIONS................................................................................................................................................................................................................... 13
REGULATORY COMPLIANCE.....................................................................................................................................................................................14
Notice for FCC.................................................................................................................................................................................................................14
Radio Notice for FCC.................................................................................................................................................................................................15
Notice for Industry Canada.................................................................................................................................................................................15
Radio Notice for Industry Canada.................................................................................................................................................................15

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SAFETY WARNINGS AND GUIDELINES
After receiving the product and before applying power, install the tubes by
following the instructions in the SETUP section, and ensure that they are properly
seated in their sockets.
Do not turn on the amplifier without first connecting a pair of 4~8 ohm speakers.
Only connect an audio component with a phono-level output to the Phono input!
Connecting a line level device will overload the circuit and can cause permanent
damage to the amplifier.
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.
If operating this device in a humid environment, ensure that no condensation
occurs. Condensation could cause a short circuit, which could cause fire or severe
electric shock.
Use only in a well-ventilated area. Do not use in close, confined spaces.
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.
Do not expose this device to excessive vibration.
Do not subject this device to extreme force, shock, or fluctuations in temperature or
humidity.
Disconnect the unit from the power source when replacing the fuse. Replace the
fuse only with the same type or the type listed in the SPECIFICATIONS section of
this manual.

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Unplug this device from the power source if it will go unused for a long period of
time.
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, as listed in the
SPECIFICATIONS section of this manual.
This device uses a grounded power cord and requires a ground connection for safe
operation. Ensure that the power source has a proper ground connection. Do not
modify the plug or use a "cheater" plug to bypass the ground connection.
Do not allow the power cord to be crimped, pinched, stepped on, etc. 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.
Ensure that power is turned off and disconnected before making any electrical
connections, including audio level connections.
Unplug the device from the power source before performing any cleaning.
Clean using a soft, dry cloth only. Do not use chemical cleaners, solvents, or
detergents. For stubborn deposits, moisten the cloth with warm water.
Keep out of reach of children.
Keep away from corrosive materials.
Do not touch the tubes while the amplifier is powered on. After removing power
from the amplifier, wait until the tubes have had a chance to cool down before
touching them.
Wait at least 10 seconds after powering on the amplifier to allow it to properly
warm up before applying a music signal.

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INTRODUCTION
Thank you for purchasing this tube amplifier from Monoprice!
This amplifier uses vacuum tubes for both the preamplifier section and the power amplifier
stage. The advantage of listening to a sound system utilizing tubes is a warmth and depth
of sound not possible with systems that are only digital or analog solid state. There are
however some things you should know if you are a first time user of classic tube amp
designs.
1. Transformer hum: The nature of tubes and transformers can produce a natural hum
emanating from the transformer. This hum should not be audible through the
speakers, but can be concerning for first time users. As long as moderate listening
levels mask the hum, there is nothing wrong with your amplifier.
2. Tubes generate heat: Be sure to always keep items clear of this tube amp. When the
amp is used for prolonged periods of time, the tubes will generate a considerable
amount of heat. Let the amp cool off before moving it after use. The heated
elements of the tube are very fragile and get damaged easily if shaken after use.
This amp includes a line level stereo RCA input, a phono-level input for connecting a
turntable, and a Bluetooth® 4.0 radio with the aptX™audio codec for wireless connections
with mobile devices.
FEATURES
Tube preamplifier and power amplifier designs
Built-in Bluetooth® 4.0 radio with aptX™audio codec
One line-level stereo RCA input
One phono-level stereo RCA input for connecting a turntable
5-way binding posts for speaker level outputs
Classic, lighted analog VU meter design

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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 [email protected]
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 Pure tube integrated amplifier
1x Bluetooth® antenna
4x EL84 vacuum tubes
3x 6N3 vacuum tubes
1x AC power cord (NEMA 5-15 to IEC 60320 C13)
1x User's manual

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CONTROLS AND CONNECTIONS
Front Panel
1. POWER: Toggles power on/off. When power is on, the LED above the power button
is illuminated.
2. TREBLE: Adjusts the high frequency response from -6dB to +6dB.
3. BASS: Adjusts the low frequency response from -6dB to +6dB.
4. VU METER: Displays the audio signal level on a scale of -20dB to +3dB.
5. BT/AUX/PHONO: Selects which of the three inputs will be used.
6. VOLUME: Adjusts the output volume level.
Rear Panel
7. BT ANT: SMA connector for attaching the included Bluetooth Antenna.
8. AUX: Line-level left and right RCA jacks for input from a CD player (or other line-
level audio source).

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9. PHONO: Phono-level left and right RCA jacks for input from a turntable with phono-
level output. Warning! Do not connect a line-level source to this input. Ensure that
you are only connecting a phono-level turntable!
10. PRE OUT: Left and right line-level RCA jacks for connecting another power amplifier
or powered speakers. The output level of the PRE OUT jacks is unaffected by the
volume knob.
11. R: Two 5-way binding posts for connecting the positive and negative leads to the
right channel speaker.
12. L: Two 5-way binding posts for connecting the positive and negative leads to the
left channel speaker.
13. AC IN: Combination power input socket and fuse holder. Plug the included AC
power cord into the IEC 60320 C14 panel connector.
CABLE PREPARATION
You will need several types of cables for this installation. None of the cables or connectors
mentioned in this section are included with the system.
Important Safety Note! If you plan on running any of these cables through the walls,
through a connecting floor, or inside an air duct, they should be rated for In-Wall, Riser
(between floors), or Plenum (air duct) use, respectively. Using unrated or improperly
rated cables could accelerate the spread of any fire and could nullify insurance claims.
Speaker Wires
You will need speaker wire to connect each speaker to the amplifier. The size (AWG) of
wire you choose depends on the distance from the amplifier to the speaker(s), the speaker
impedance, and the physical limits of the terminals at each end.
Other than saving a few pennies of cost or grams of weight per foot, there is no reason to
use anything other than the thickest wire possible. This amplifier can accept up to 7 AWG
wire, so it is recommended to use 10 or 12 AWG speaker wire. If the speaker terminals

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cannot accept 10 or 12 AWG wire, you can use banana or pin plugs to connect the wire to
the speaker terminals.
Whichever speaker wire you get, make sure that it has marks to identify one conductor
from another. Most speaker wire uses a colored stripe to identify one of the conductors.
The identified conductor is usually used for the positive (+/red) connection and the other
for the negative (-/black) side.
Note: When cutting speaker wire, ensure that the length of each stereo pair is the
same. This ensures that the overall impedance of each channel is identical. If there is
any excess speaker wire, it should not be coiled, as it could create an antenna to
receive stray radio signals. Instead, snake the excess wire back and forth.
RCA Cables
You will need stereo RCA cables to connect the CD player or other source device to the
amplifier's source inputs. In most cases these will be relatively short connections, so
ordinary RCA cables are sufficient. However, if the distance is longer than about 15-20 feet
(4.5-6 meters), it is recommended to use RCA cables manufactured using shielded RG6 or
RG59 cable. RG59 can connect to distances up to about 131 feet (40 meters), while RG6 can
make reliable connections to distances up to about 328 feet (100 meters).
SETUP
Note: Before making any connections, ensure that all equipment is powered off and
unplugged to prevent the possibility of personal injury or equipment damage due to
electrical shock.
Tubes
To prevent damage during shipping, your Pure Tube Stereo Amp ships with the tubes
uninstalled. Perform the following steps to install the tubes.
1. Remove one of the EL84 tubes from its box. The EL84 is the larger of the two tube
types.

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Use gloves when handling the vacuum tubes to prevent oil residue from your
fingers accumulating on the glass, thereby preventing premature tube failure.
2. Position the tube inside one of the four large tube cages. Align the pins to match
the pattern in the tube socket, with the large gap closest to the rear of the amp.
Gently push the tube into the socket. You may need to gently wiggle or rock the
tube to help overcome resistance from friction. Ensure that the tube is firmly seated
in the socket.
3. Using the same procedure, insert the other three EL84 tubes into the large tube
cages. Ensure they are fully seated.
4. Using the same procedure, insert the three 6N3 tubes into the three smaller tube
cages. Ensure they are fully seated.
5. Position the amplifier in a location in which it can get adequate airflow around the
case and ventilation holes. Do not connect the power cord yet.
Speaker Connections
6. Measure the distance between the amplifier and the speakers, taking into account
the need to route the wire around furniture or other obstacles. Cut two lengths of
2-conductor speaker wire to the measured length. It is best to cut the wires longer
than needed as any excess can be trimmed later.
7. Connect one end of one of the speaker wires to the left-channel Speaker Output
five-way binding posts on the rear panel, taking care to connect the negative side
of the wire to the negative (black) binding post and the positive side of the wire to
the positive (red) binding post. The easiest and safest method of connecting the

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wires to the binding posts is to use banana plugs. If using bare speaker wire,
carefully inspect each connection to ensure that there are no stray wire strands.
8. Connect the other end of this speaker wire to the inputs on your left-channel
speaker, taking care to match the polarity. If using bare speaker wire, carefully
inspect each connection to ensure that there are no stray wire strands.
9. Repeat steps 4-5 for the right channel.
Source and Power Connections
10. Plug the Bluetooth antenna into the BT ANT connector on the rear panel. Tighten
the thumbscrew to secure it in place, then position the antenna vertically.
11. Plug one end of a stereo RCA cable (not included) into the AUX inputs on the rear
panel, taking care to plug the right channel plug (red) into the red RCA jack and the
left channel plug (usually black or white) into the white RCA jack.
12. Plug the other end of the RCA cable into the audio output jacks on your CD player
(or other source device), taking care to plug the right channel plug (red) into the red
RCA jack and the left channel plug (usually black or white) into the white RCA jack.
13. Most turntables with phono-level output use integrated cables that are
permanently connected to the turntable. Plug the turntable cable into the PHONO
inputs on the rear panel, taking care to plug the right channel plug (red) into the red
RCA jack and the left channel plug (usually black or white) into the white RCA jack.
14. If the cable is not integrated with the turntable, plug the other end of your cable
into the turntable's RCA output jacks, taking care to plug the right channel plug
(red) into the red RCA jack and the left channel plug (usually black or white) into the
white RCA jack.
15. If the turntable has a switchable, built-in preamplifier, turn it off.
16. Plug the included AC power cord into the AC IN socket on the rear panel. Plug the
other end into a nearby AC power outlet.

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Bluetooth Connection
This amplifier features a built-in Bluetooth® radio with a range of up to 32 feet (10 meters)
for streaming audio from your mobile device. It can remember up to 8 pairings and will
automatically drop old connections when pairing with a full list. Perform the following
steps to connect your mobile device to the amplifier's Bluetooth radio.
17. Depress the power button on the front panel to turn the amplifier ON.
18. Flip the BT/AUX/PHONO to the BT position.
19. Open the Bluetooth settings on your mobile device and initiate a scan for nearby
Bluetooth devices.
20. Locate and select the MP TUBE 27222 entry. If prompted for a passcode, enter four
zeroes (0000).
Congratulations! Your amplifier is now properly setup and ready for use!
MAINTENANCE
Note that after years of use, vacuum tubes will not perform as well as when they are new.
This may result in audible distortion at moderate volume levels. If this occurs, you should
replace the vacuum tubes with new tubes of the same type. Since these are not power
tubes and no biasing is required, you can safely replace them yourself.
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
during regular business hours, 7 days a week. You can also get assistance through email by
sending a message to [e-mail]

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SPECIFICATIONS
Model
27222
Inputs
Bluetooth® (BT), Line-level (AUX),
Phono-level (PHONO)
Frequency Response
20Hz ~ 20kHz (-2dB)
Total Harmonic Distortion (@1kHz)
1%
RMS Power Output (4-ohm load @ 1kHz)
10 watts/channel
Output Impedance Range
4 ~ 8 ohms
Input Impedance
47 kilohms
Input Sensitivity
450mV
Signal-to-Noise Ratio
≥ 85dB
Treble Adjustment Range
-6dB ~ +6dB
Bass Adjustment Range
-6dB ~ +6dB
Input Voltage
100 ~ 120 VAC, 60 Hz
Fuse Ratings
F2AL/125V
Tube Types
EL84 and 6N3
Bluetooth Version
4.0 with aptX™audio codec
Bluetooth Range
Up to 32 feet (10 meters)
Bluetooth ID
MP TUBE 27222
Dimensions
10.7" x 5.9" x 12.4" (272 x 150 x 315 mm)
Weight
16.1 lbs (7.3 kg)

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REGULATORY COMPLIANCE
Notice for FCC
This device complies with Part 15 of the FCC rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
Modifying the equipment without Monoprice's authorization may result in the equipment no
longer complying with FCC requirements for Class B digital devices. In that event, your right to use
the equipment may be limited by FCC regulations, and you may be required to correct any
interference to radio or television communications at your own expense.
This equipment has been tested and found to comply with the limits for a Class B digital device,
pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection
against harmful interference in a residential installation. This equipment generates, uses and can
radiate radio frequency energy and, if not installed and used in accordance with the instructions,
may cause harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment
off and on, the user is encouraged to try to correct the interference by one or more of the
following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the receiver
is connected.
Consult the dealer or an experienced radio/TV technician for help.

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Radio Notice for FCC
Caution
This FCC Part 15 radio device operates on a non-interference basis with other devices operating at
this frequency. Any changes or modification to said product not expressly approved by Monoprice,
including the use of non-approved antennas, could void the user’s authority to operate this device.
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) this device may not cause harmful interference, and (2) this device must accept any
interference received, including interference that may cause undesired operation.
Notice for Industry Canada
This Class B digital apparatus complies with Canadian ICES-003.
Cet appareil numérique de la classe B est conforme à la norme NMB-003 du Canada.
Radio Notice for Industry Canada
Caution
This IC RSS-210 radio device operates on a non-interference basis with other devices operating at
this frequency. Any changes or modification to said product not expressly approved by Monoprice,
including the use of non-approved antennas, could void the user’s authority to operate this device.
This device complies with IC RSS-210. Operation is subject to the following two conditions: (1) this
device may not cause harmful interference, and (2) this device must accept any interference
received, including interference that may cause undesired operation.
The Bluetooth® word mark and logos are registered trademarks of Bluetooth SIG, Inc.
Qualcomm® is a trademark of Qualcomm Incorporated, registered in the United States and other
countries. aptX™ is a trademark of Qualcomm Technologies International, Ltd., registered in the
United States and other countries. Qualcomm® aptX™ is a product of Qualcomm Technologies
International, Ltd.