MQ-88UC
VACUUM TUBE STEREO POWER AMPLIFIER
MQ-88uC
Owner`s Manual
Contents
Precautions ············································································································· 1
Features of This Unit ································································································ 2
Names and Functions ······························································································ 4
Connections ············································································································ 6
Block Diagram ········································································································· 8
Specifications ·········································································································· 9
Before Asking for Repair Service ············································································ 10
VACUUM TUBE STEREO POWER AMPLIFIER MQ-88uC
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 holes
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.
* Note
Cautions in connecting speakers
When making speaker system connections, be sure not to
cause short-circuiting between ! and @ of the speaker ter-
minals 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.
* *
*
Wall
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 prod-
uct 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 inade-
quately connected, noises including hum may be generated,
resulting in an adverse S/N ratio.
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 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
installation.
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.
1
Features of This Unit
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 Slovak Republic.
Necessary and sufficient rated output
The rated output of 25 W+25 W (at the load of 4, 8, and
16Ω) that enables necessary and sufficient sound volume in
various speaker environments.
Output tube, KT88
KT88 manufactured by JJ Electronic in 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.
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 an 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.
Impedance matching
Speaker terminals dedicated for 4, 8, and 16 Ω are equipped,
which can be used according to the impedance of the speak-
ers to be used.
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VACUUM TUBE STEREO POWER AMPLIFIER MQ-88uC
Bonnet for vacuum tube
A mesh type bonnet is supplied as a standard item to protect
vacuum tubes and other large-sized parts.
Wide pitch RCA terminals
Wide pitch RCA terminals are used to allow large-sized RCA
cables to be connected.
Custom-made parts
LUXMAN’s original custom-made parts for generating high
sound quality are plentifully equipped.
Highly reliable design
Prolonged life and highly reliable design have been achieved
by providing operating conditions of vacuum tubes with some
allowance.
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