Japanese model 100v - step down transformer needed Need a service - treble on right channel need attention/repair
Pre-main amplifier with DUO β circuit / S.
We
have developed the DUO β Circuit / S, which combines an "appropriate
amount NFB" and a "DC-servo", and the DUO β Circuit / S, which adds a
"single-stage amplifier" in addition to the control feedback power
supply plusX, which is superior in sound quality. These circuits are
installed in the equalizer and power section. The first stage
amplifier uses an FET for the MC head amplifier in the first stage.
Originally, this FET has high gm and low noise, and it has a structure
in which a large current of 7 mA per 1 stone is applied to obtain the
necessary gain. At the same time, the output stage is completely
independent so as not to affect the first stage, and the second stage is
removed. This realizes an ideal circuit with only one stage for voltage
amplification.
The output section has an intrinsic class A operation with fixed bias current, and realizes a large output of 50W/ch. The
large amount of heat generated by class-A operation is handled by two
large heat pipes, which are symmetrical in shape to eliminate heat
radiation noise.
A single-stage amplifier is also used for the head amplifier. The
PNP transistor with very low input equivalent resistance at the first
stage is made to be single differential, and low noise is realized while
obtaining sufficient gain.
It is equipped with a phono straight
function that separates the input selector, filters, monaural switch,
balance control, etc., and connects the equalizer and power amplifier
directly.
In some cases, the recording frequency of a disc, etc.,
rises gradually toward the high frequency range, and in other cases, it
falls. Therefore, a linear equalizer is incorporated to correct this
tendency and return the recording characteristics to a flat level.
It is equipped with a tone control that allows you to select nine turnover frequencies for both high and low frequencies. It
is designed with emphasis on the frequency at which the change starts
rather than the amount of change, and uses the NF type Lux-style tone
control that can obtain straightforward change characteristics.
The
power supply section uses a special EI core with a capacitance of 400
VA, and a power transformer with the inside hardened by 哇砂 to suppress
temperature rise. Two electrolytic capacitors with an aluminum purity of 99.99% and a capacity of 30,000 μ F with sound quality measures are used.
Equipped with a pre-heating function, it can be heated by passing a small amount of current.
Equipped with a warm-up indicator, it is possible to confirm that stable operation has started.
Equipped with a line phase sensor, it can control sound quality by detecting the polarity of the AC power supply in the process.
Type Integrated amplifier Effective power 50W + 50W (Class A Operation, 8 Ω, Double-channel Operation) Total harmonic distortion factor 0.005% or Less (8 Ω, Both Channel Operation, -3dB) Input sensitivity Phono MM:1.6mV Phono MC : 80 μ V Tuner, AUX, Monitor, Main In : 220 mv Input impedance Phono MM : 100k Ω, 50k Ω, 100 Ω Phono MC : 300 Ω, 100 Ω, 40 Ω Tuner, AUX, Monitor : 40k Ω Main In : 47k Ω Signal-to-noise ratio (IHF-A) Phono MM:84dB Phono MC : 80 dB (250 μ V input) Tuner, AUX, Monitor, Main In : 110 dB Frequency characteristic 10 Hz to 100 kHz -1dB Tone control Low turnover : 55 Hz, 77 Hz, 110 Hz, 155 Hz, 220 Hz, 310 Hz, 440 Hz, 620 Hz, 820 Hz High turnover : 620 Hz, 880 Hz, 1.2 kHz, 1.7 kHz, 2.5 kHz, 3.5 kHz, 5 kHz, 7 kHz, 10 kHz Maximum variation : + / - 9 dB Tape monitor Route 3 (Tape1, 2, Tape Front) Tape dubbing 4 systems (1 → 2, 2 → 1, 1 → Front, Front → 1) Linear equalizer Up tilt, down tilt : 2 steps each (1 step 1 dB) Power consumption 310W External dimensions Width 453x Height 174x Depth 460 mm Weight 21.4kg