Luxman MQ-88uC Vacuum Tube Stereo Power Amplifier User Manual

Luxman MQ-88uC Vacuum Tube Stereo Power Amplifier

Precautions

Installation place
Install this unit in a location where good ventilation and heat radiation are assured. Especially, installation of this unit where direct sunlight is present, where the temperature rises exces-sively high such as close to a heater, or where it is humid or dusty may cause a malfunction even if heat is efficiently released. Therefore, do not install this unit in such places.

Ventilation hole s
The ventilation holes on the top and bottom boards of this product must not be blocked because this unit is a vacuum tube amplifier and generates considerable heat. If the ampli-fier is installed on a rack or the like, secure ample space for cooling and leave the door open. Do not pile up other things on the amplifier and never put articles on it. Failure to observe this may cause a malfunction.

Note: For heat dispersal, do not install this equipment in a confined space such as a book case or similar unit.

Precautions in connecting with other components

When connecting this product to input devices such as a control amplifier, be sure to turn off the power of this product and all other connected devices. Otherwise, a very strong noise may be generated and destroy the speakers. In the worst case, this can cause equipment malfunction. The pin plug to be inserted in each input terminal of this unit shall be pushed in firmly. If the grounding terminal is inadequately connected, noises including hum may be generated, resulting in an adverse S/N ratio.

Cautions in connecting speakers
When making speaker system connections, be sure not to cause short- circuiting between! and @ of the speaker terminals and speaker input terminals of this unit. If signals are applied to the amplifier with its circuit left short-circuited, a large current may be carried in the output circuit and cause malfunctioning.

The sound is not generated shortly after the power supply is turned on.
This product is a vacuum tube amplifier, and therefore, it can-not deliver a sound until the vacuum tube heaters warm up. You can enjoy music 1 minute or more after turning on the power. We therefore advise initially setting the volume control at a low level. After that, you may move the volume control to your favorite sound level after the initial sound comes out of the speakers.

Repair and adjustment
When repairs and adjustments are needed, please consult with the dealer where you bought the unit.

Cleaning
For cleaning, use a piece of soft cloth to wipe the unit such as cleaning cloth. When the dirt is hard to remove, use a small amount of neutral detergent to wipe, and then wipe the unit with a dry cloth. Do not use a solvent like benzine or thinner because such a substance can damage the exterior.

Safety caution

Caution

• This unit is heavy. Be careful when unpacking, carrying, and installing.
• This unit is a vacuum tube control amplifier. In the state of the unit in operation, the main body gets hot. Be careful not to touch it with your bare skin. For safety, do not use this product in a place where children or unchained animals are present.

Design of using vacuum tubes for all amplification circuits
All the amplification circuits consist of vacuum tubes (ECC83S x 2 pieces, ECC82 x 2 pieces, and KT88 x 4 pieces) that are manufactured by JJ Electronic in the Slovak Republic.

Necessary and sufficient rated output
The rated output of 25 W+25 W (at the load of 4, 8, and 16 Ω) that enables necessary and sufficient sound volume in various speaker environments.

Output tube, KT88
KT88 manufactured by JJ Electronic in the Slovak Republic is used in the push- pull structure as an output tube, which has the reputation of powerful and thick tone quality.

Parallelized first stage
The amplifier on the first stage has been parallelized and directly connected to the driver stage with a high S/N ratio and low-impedance transmission.

Triode connection
The proven Mullard-type circuit (for the driver stage) has been equipped, and KT88, an output tube, has been used in a way of triode connection.

Impedance matching
Speaker terminals dedicated to 4, 8, and 16 Ω are equipped, which can be used according to the impedance of the speakers to be used.

Old-time parts layout
This product has a parts layout inspired by the design of old-time masterpiece, MQ60.

Monocoque chassis structure
This product features a monocoque chassis structure that is orthodox and has been proven.

OY-15 output transformer
The OY-15 output transformer contained in an aluminum die casting case has been revived in its original shape.

Large-capacity power transformer
An EI-type large-capacity power transformer is used to obtain persistent tone quality.

LUXMAN’s original block capacitor
LUXMAN’s original large-sized block capacitor is used to supply stable power.

2-line input
There are two lines of inputs for input terminals; one is a variable input capable of sound volume adjustment, and the other is a direct input to bypass the volume.

Bonnet for vacuum tube
A mesh-type bonnet is supplied as a standard item to protect vacuum tubes and other large-sized parts.

Custom-made parts
LUXMAN’s original custom-made parts for generating high sound quality is plentifully equipped.

Wide-pitch RCA terminals
Wide-pitch RCA terminals are used to allow large-sized RCA cables to be connected.

Highly reliable design
Prolonged life and highly reliable design have been achieved by providing operating conditions of vacuum tubes with some allowance

Names and Functions

Front panel

1. Operation indicator (OPERATION)
   Turns orange when the power is turned on.

2. Operation switch (OPERATION)
   Toggles the power on and off. When wiring or connection is performed, be sure to turn off this switch. When turning on the power switch again after turning the unit off, wait for more than one minute.
   When the power is turned off, the OPERATION indicator will stay on for a while, but it is not a malfunction

3. Volume control (VOLUME)

   • This function is effective only when a source component such as a CD player is connected to the VARIABLE input of this unit to adjust the input level.
   • When the connection is made with the direct input (DIRECT), the signals do not go through this volume thus the sound volume does not change.
   • When the DIRECT input is connected, please take extra care for the volume of the other connected unit.

Rear panel

Direct input terminals (DIRECT)

• Connects to a control amplifier or a source component.
• When connected to this input terminal, the signals do not go through the volume circuit, thus rotating the volume control on the front panel will not change the volume.

Variable input terminals (VARIABLE)

• Connects to a source component, e.g. a CD player without output level control.
• The sound volume can be adjusted by the volume control of the front panel.
• If using a control amplifier with high output impedance in combination with this unit, use of the connection cable as short as possible is recommended to avoid unnecessary treble attenuation.

Input selector (VARIABLE/DIRECT)

• Variable or direct input can be switched.

• Select the name of the terminals connected to the device to playback by operating this switch.
  When switching the input, be sure to turn off the power.
  If the power is on while switching, a loud noise might be generated

• Speaker terminals (SPEAKERS)
  These terminals are output terminals to connect a speaker system.
  The right speaker terminals shall be connected to the R side, and the left speaker terminals shall be connected to the L side in consideration of the polarity+and -.
  The speaker terminals consist of + COMMON,-4Ω, + 8Ω, and ! 16Ω for each channel. Connect the + terminal of the speaker system to the + COMMON terminal and + terminal of the speaker system to + 4Ω, + 8Ω, or + 16Ω according to the impedance of the speakers to be used.

Connections

Before connecting
Before connecting other devices, connect the jack side of the accessory power cable to the AC inlet of this unit.
Before a connection is made, turn off the main power switch of this unit and the power of all other connected devices to prevent accidents due to noises generated unexpectedly

How to connect the power supply
Use the accessory power cable and insert the AC plug in the outlet on the wall in the room where the unit is installed.

How to connect a CD player, control amplifier

• Connect the output terminal of a control amplifier to the input terminal with 2 (R and L) pin-plug cables.
• When using a source device with the volume adjusting function, such as a CD player, connect to the VARIABLE input terminal. When using a source device with the volume control, such as a control amplifier, connect to the DIRECT input terminal.
  Select DIRECT or VARIABLE input with the input selector.

How to connect speakers
Connect the left-channel speaker to the SPEAKERS-L terminal of this unit and the right-channel speaker to the SPEAKERS-R terminal.
Securely connect the + terminal of the speaker system to the red speaker terminal (+ 4Ω, +8Ω, or +16Ω) of this unit according to the impedance of the speakers to be used and the – terminal of the speaker system to the black speaker terminal (- COMMON) of this unit. If the + or – terminal is reversely connected to either of the right or left of the speaker system, the signal phases reproduced from the right and left of the speaker system are also reversed. In such a case, be aware that the sound level in the low range will be reduced and the acoustic stability will worsen, and thus the normal stereo playback is not achieved.

If the impedance of the speakers to be used is other than 4Ω, 8Ω, or 16Ω, connect the terminal with an impedance closest to the impedance value of the speakers.
The range of the impedance of the speaker to be connected should be within the range of 4Ω to 16Ω.

Block Diagram

Specifications

0.5 % (20 Hz to 20 kHz, 1 W)

Input sensitivity| 890 mV/25 W
Input impedance| 32 kΩ
S/N ratio| 105 dB (A weighted, input short)
Frequency response| 20 Hz to 20 kHz (+0, −0.2 dB)

10 Hz to 100 kHz (+0, −3.0 dB)

Input| Line: Direct input x 1 line, variable input x 1 line
Output| Speaker terminal x 1 line (4, 8, and 16 Ω independent)
Supplied functions| [Front panel] Operation switch, Volume control [Rear panel]  Input terminal, Input selector, Speaker terminal, AC inlet
Circuiting system| Mullard
Vacuum tube used| ECC83S x 2 pieces, ECC82 x 2 pieces, and KT88 x 4 pieces
Accessories| • Power cable                                    • Terminal protection cap

• Owner’s Manual (This document)         • Safety cautions

Power source| 230 V 〜 (50 Hz)
Power consumption| 170 W

140 W (no signal)

Max. external dimensions| 440 (W) x 184 (H) x 230 (D) mm
Weight| 16.1 kg (main unit)

Before Asking for Repair Service

While in use, this unit may display phenomena that may be confused as malfunctions. Before contacting your country’s official LUXMAN distributor for repair services, please read the operating instructions and operating instructions for any connected input and output devices and check the troubleshooting table below. If the cause of the malfunction cannot be identified, please contact your dealer. After LUXMAN’s representatives have accepted your request for repair services, inspection fees, and transportation expenses may be claimed, even though the unit may be found to be operating normally.

0.5 % (20 Hz to 20 kHz, 1 W)

Input sensitivity| 890 mV/25 W
Input impedance| 32 kΩ
S/N ratio| 105 dB (A weighted, input short)
Frequency response| 20 Hz to 20 kHz (+0, −0.2 dB)

10 Hz to 100 kHz (+0, −3.0 dB)

Input| Line: Direct input x 1 line, variable input x 1 line
Output| Speaker terminal x 1 line (4, 8, and 16 Ω independent)
Supplied functions| [Front panel] Operation switch, Volume control [Rear panel]  Input terminal, Input selector, Speaker terminal, AC inlet
Circuiting system| Mullard
Vacuum tube used| ECC83S x 2 pieces, ECC82 x 2 pieces, and KT88 x 4 pieces
Accessories| • Power cable                                    • Terminal protection cap

• Owner’s Manual (This document)         • Safety cautions

Power source| 230 V 〜 (50 Hz)
Power consumption| 170 W

140 W (no signal)

Max. external dimensions| 440 (W) x 184 (H) x 230 (D) mm
Weight| 16.1 kg (main unit)

Specifications and the appearance are subject to change without notice.

While in use, this unit may display phenomena that may be confused as malfunctions. Before contacting your country’s official LUXMAN distributor for repair services, please read the operating instructions and operating instructions for any connected input and output devices and check the troubleshooting table below. If the cause of the malfunction cannot be identified, please contact your dealer. After LUXMAN’s representatives have accepted your request for repair services, inspection fees, and transportation expenses may be claimed, even though the unit may be found to be operating normally.

• Insert the power plug in the wall outlet completely.
• The power plug is disconnected from the AC inlet, or it is not inserted completely.| • Securely insert the power plug in the AC inlet.
No sound is generated.

(for both left and right channels)

| • The volume control is set at the minimum level.| • Rotate the volume control clockwise to adjust the sound volume.
• The input switch is not set to the position of the source to be played back.| • Set the input switch to the position of the source to be played back.
• Cable connections are incomplete.| • Make cable connections securely.
• The output level of the input device is set to the minimum position.| • Adjust the output level.
No sound is generated on one side.| • The connecting cable is not connected on one side only.| • Make cable connections securely.
Humming sound (boon or zzz noise) is generated.| • The ground side of the pin- plug cable has no contact with the terminal.| • Make connections securely so that the ground side of the pin-plug cable can be connected.
• The connecting cables are too close to the power cable.| • Keep the connecting cables away from the power cable.
• Induction noise is picked up from a power transformer of another device.| • Install it distant from other devices.

LUXMAN CORPORATION, JAPAN
1-3-1 Shinyokohama, Kouhoku-ku, Yokohama-shi, Kanagawa 222-0033, Japan

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