Commentary

Stereo control amplifier designed for high-end audio systems.

The panel layout is completely unique with a push switch. The circuit configuration is a class A DC system with a symmetrical push-pull drive for all amplification stages.
Elements that affect sound quality are also used.

The panel face consists of four rotary knobs, one lever switch and 57 push switches.
In particular, the input selector is electronically controlled to control the relay in the circuit, and can be switched by feather touch.
By taking advantage of the electronic control system, it is possible to store ON/OFF information for each cartridge in accordance with DISC1 and DISC2.
Also, in order to improve contact resistance of push switches and relays which affect sound quality and durability, all of them are constructed using two circuit arrangement.

A fully symmetrical push-pull circuit is used from the head amplifier inlet to the output and in all the amplification stages of the headphone amplifier. This circuit has excellent linearity and achieves the best distortion rate with a small amount of NFB. As a result, TIM (transient intermodulation) distortion, which is one of the causes of sound quality degradation, is improved.
All of the unit amplifiers (head amp, equalizer amp, high-level amp and headphone amp) are DC-type. The condenser for cutting DC of the NF loop, which requires a large capacity, is removed. Moreover, the input condenser is removed, and the ICL method is used to improve sound quality.

The head amplifier has an input differential push-pull configuration. It uses a specially developed RET (ring emitter transistor) for small signals, contributing to improved sound quality. In addition, the output impedance is reduced by driving the output stage with a large current, and the input conversion noise is reduced by setting the feedback voltage dividing resistance low.
In addition, the head amplifier is modularized so that it can operate stably even in temperature change without humidity.

The equalizer amplifier consists of symmetrical push-pull amplification stages through the FET buffer of the input.
The EQ uses RET (Ring-Emitter Transistor) for high-frequency power amplification, A class large current drive for low output impedance, and low feedback voltage dividing resistance. At the same time, the input conversion noise level close to the ideal limit can be obtained by using high gmFET for the input buffer.

The high-level amplifier (flat amplifier) uses the DC servo method (PAT, PEND) so that it can operate as a DC amplifier even when the tone control is in use, reducing DC drift to almost zero.
The DC servo system eliminates the need for an output capacitor, and there is no capacitor for cutting DC from the Tuner and AUX jacks to the output.

The headphone amplifier is equipped with a PureCon headphone amplifier.

The volume consists of 18 brushes with sliding elements, and the resistor consists of a mirror-finished conductive plastic element.
A film resistor with a continuous array of conductive particles is integrally molded on an insulator made of thermosetting resin. It has a smooth and strong film surface.
With 18 sliding elements and conductive plastic elements, the contact resistance is theoretically reduced to 1/18 and the volume is stable for a long time.

Electromagnetic cartridges are characterized by high frequency peaks due to resonance of vibration system, inductance of coil and wiring tray capacity.
In order to adjust the high-frequency characteristics of such a cartridge, HF trimming is, and it can be continuously changed from a flat state to -8dB at 20 kHz.
It is dedicated to DISC1 and DISC2 and can be controlled according to each cartridge.

The tone control turnover switch allows you to control the deep bass and highest range by using the turnover of 500 hz and 200 hz for bass, 2 khz for treble, 200 hz for 7 khz and 7 khz for treble. The switching is a 2 db step.

Equipped with a Loudness Compensator switch to compensate for the sense of hearing at low volume and adjust the energy balance.
You can choose from three curves depending on the playback level and listening room characteristics.

Only a 17 Hz, 12 dB subsonic filter is installed to make the filter practical.
CR is added to the input element of the high-level amplifier to form an active filter.
There is no additional dedicated active element, so there is no sound degradation.

Two tape recorders can be connected, and independent copy switches allow for mutual dubbing while listening to other program sources.
There is also a recording output ON-OFF switch that is convenient for cutting unnecessary programs.
This switch is also effective to prevent distortion caused by the load of the control center from the input circuit when the power of the tape recorder is turned off.

The attenuator switch is used to find the starting point of a record or to switch between records. In addition to the attenuator switch, there are three levels of attenuation available : -10dB, -20dB and -30dB.

In addition to stereo, rev blend position in addition to Stereo, Rev and Mono.
This is for use when the speakers are too far apart, or when playing back a source that unnaturally separates program sources. The left / right spread is reduced to 10 dB, which is a natural spread.

One of the power Route 3 is equipped with a Canon power connector.

It is stored in a natural wood Rosewood cabinet.

Model Rating

Type	Stereo Control Center
Frequency Response	High level input : 20 Hz to 20000 Hz + 0 -0.2 dB Disk input : 20 Hz to 20000 Hz ± 0.2 dB
Harmonic Distortion Factor	0.005% (between 20 Hz and 20 kHz, rated output)
Input Sensitivity / Input Impedance	DISC1, 2 (Head Amp OFF) : 2.0mV/100 Ω, 47k Ω, 82k Ω, 150k Ω switching DISC1, 2 (Head Amp ON) : 0.1mV/100 Ω fixed Tuner, AUX, Tape Play1, 2 : 126mV/50k Ω
Rated Output / Output Impedance (Volume max, nominal input)	Output : 2.0V/2 Ω Tape Rec1, 2 : 126mV/500 Ω
Headphones	Output impedance : 0.3 Ω Output (8 ohm load) : 0.25W, 1 kHz, Distortion 0.01%
Maximum power level (20 Hz to 20 kHz)	10 v or more, strain 0.005%
Disk Max Input	Head Amp OFF : 400 mVrms, 1 kHz, Distortion 0.005% Head Amp ON : 20 mVrms, 1 kHz, Distortion 0.005%
Minimum Load Impedance	Outputs : 1k Ω Tape Rec : 10k Ω
Gain	from Tuner, AUX, Tape Play Tape Rec: 0dB Outputs: 24dB HeadPhones: 20dB from DISC (Head Amp OFF) Tape Rec: 36dB Outputs: 60dB HeadPhones: 56dB (+ 26 dB at DISC input HEAD AMP ON)
S/N / Input Conversion Noise (input short, IFF-A, Rated input)	High level input : 110dB/-128dBV Head Amp OFF : 85dB/-139dBV Head Amp ON : 72dB/-152dBV
Tone Controls	Switchable by 8-step push switch Bass 500 Hz : + / - 8 dB (50 Hz) 200 Hz : ± 8 dB (20 Hz) 2 dB step 2 dB steps Treble 2 kHz : ± 8 dB (20 kHz) 7 kHz : ± 8 dB (50 kHz) 2 dB step 2 dB steps
Loudness Compensator	COMP1:+6dB(50Hz) COMP2:+9dB(50Hz) COMP3 : + 10 dB (50 Hz), + 6 dB (20 kHz) (volume control, -30dB)
Disk High Trim	DISC1, DISC2, 0 dB to -8dB continuously variable (at 20 kHz)
Attenuator	-10dB, -20dB, -30dB switchable
Subsonic Filter	17 Hz, 12dB/oct
Semiconductors used	159 tr, 10 fet, 102 di
Power Supply	100 V, 117 V, 220 V, 240 V, 50/60Hz
Power Consumption	80W
External Dimensions	466 mm wide x 188 mm high x 391 mm deep
Weight	18kg