MQ-88 VACUUM
TUBE POWER AMPLIFIER
We, Luxman
could be said a maker who has been pursuing the possibility of adopting the
vacuum tube in amplifier for a long term in Japan. Although it happens that the
replacing into the semiconductor has become the main stream in audio
amplification, the high reality and wide range owned by vacuum tube enables it
be actively used in the design as well as in the constitution of amplification
circuit. Here comes the CL-88/MQ-88, a separate type vacuum tube amplifier
poured with the latest (development) results and everlasting enthusiasm and
republished after 11 years’ dormancy.
Driving KT88
with Mulardo type circuit
The vacuum
tube was adopted in power amplifier MQ-88 after overall careful consideration.
In the primary stage of ECC83S, JI-made vacuum tube of Slovakia, and in the
drive stage of 12BH7A and output tube of KT88, the Sobulikku–made vacuum tube
of Russia are respectively adopted. The products with a good fame in quality,
sound quality and in long term stable delivery are used. In circuit type, the
cathode directly connecting type aiming at gaining flexibility and
forcefulness, namely the Mulardo type was adopted. It features that the second
distortion occurred at the drive section of differential construction in the
primary stage could be eliminated and the balances of push-pull actions of
output tube KT88 is stabilized. In addition, the product that has same size
with OY36 which boasts wide range features and dynamic sound was specially
designed into the output transistor. Lastly, the transistor using oriented core
material was built in the sealed box for protecting it from noise.
The bias
adjusting function equipped with monitoring meter The meter using for adjusting
the bias current aiming at guaranteeing the visibility by the combination of
blue LEDs was equipped on the top panel. For keeping 4 KT88 (vacuum tubes) at
usually best conditions, and for highlighting the stability and reliability in
semi-fixed volume, the wirewound sealed construction type was adopted
The high
grade/high sound quality parts made with carefulness
This is the MQ-88 aiming at increasing the high fidelity of the amplification of
signal by decreasing the attached functions. So the parts used in this must be
in good quality. First of all, the single wire of the gold plating 4N
non-copper oxide coated with the ideal insulating material—fluorine resin
insulating coating was adopted in the signal wire. So the sound with core and
long term stable feature could be reached. In CR parts type, many best-known
parts such as tubular type condenser immersed in vitamin Q oil, the Ligen
Dengu-made carbon film resistor used in audio are adopted. In addition, many
high-grade custom-made parts such as gold-plating tight socket, super-high
insulation lug terminal plate, etc. are adequately used.
Chassis
construction completely pursuing rigidity
The
vibration and the resonance from the outside are the formidable enemy for
vacuum tube inside it the electrons collide each other in the vacuum glass
tube. For MQ-88, on the basis of guaranteeing the rigid foundation by
adopting the 15mm super-thick aluminum stainless plate for top panel, the
constructions suitable for control amplifier and power amplifier are
extensively analyzed. On one side, the
shock-proof construction integrated surface and collar of MQ-88 supports the
heavy things such as transistors, etc. Because the collars are directly
installed at the foot parts of case, the case body is kept upright. The
existing box-type part plays a role of beam in this construction, contributing
a lot for the strengthening of the horizontal intensity of the case body as a
whole. The Piezon composite insulator used at the foot parts of the two models
has taken the construction combining the advantages of hardware and software
systems by using the stainless brass combined with damping material
(piezoelectricity-type sound-proof and absorption material). It could give a
solid support to the amplifier case body as well as could eliminate the
vibration and resonance.
SPECIFICATIONS
MQ-88
Rated
Output:
40 W +
40 W (8Ω),
50 W + 50 W (6Ω),
40 W + 40 W (4Ω)
Input
Sensibility/Input Impedance: 420mV /
100kΩ
Overall
Higher Harmonic Distortion Rate:
1,5% (1 kHz rated)
Frequency
Characteristic: 5 Hz - 90 kHz (+0, -3
dB)
Signal-to-Noise
Ratio: less than 101 dB (1kHz 1HF-A)
Input: 2 Coaxial
systems (one is direct input system)
Output: Speaker Terminal 1 System
Accessory
Device: Power switch, power indicator,
input level adjusting volume, bias current adjusting volume X 4, bias
monitoring meter, line phase sensor, signal ground contact, AC inlet
Vacuum Tube
Used:
Output tube:
KT88 X 4,
The First
Stage: ECC83S X 2,
Drive Stage:
12 BH7A X 2
Circuit
Format: Murado type
Sound
Quality Parts:
Gold plating
4N non-copper oxide copper single wire,
Tubular type
condenser immersed in vitamin Q oil,
Gold-plating
tight socket,
Shock-proof
construction used in 15mm thick aluminum top panel
Power
Consumption: 190 W (Based on the Safety
Law on Electrical Appliances)
Dimension (W
x H x D): 400 x 186 x 397 mm
Weight: 25.1 Kg