Commentary

In addition to the normal line amplifier, this stereo preamplifier has a built-in CD-only amplifier for maximum sound quality.

In addition to the normal line amplifier, a CD-specific buffer amplifier is built in in order to play CDs at the marginal quality.
The CD amplifier consists of a class A push-pull -pull balance circuit in all stages. The signal enters directly from the input terminal. The functions are limited to the minimum necessary functions of volume adjustment and attenuator. This simplifies the signal path and provides a detailed and stereophonic sound field.
All stages of the line-only amplifier are A-class push-pull. It performs high-purity amplification and is equipped with the necessary functions as a preamplifier in preparation for multiple inputs.

Only a -20dB attenuator and volume control are installed in the CD signal path.
It is also equipped with balanced input / output terminals, and ideal balanced transmission is possible by connecting a balanced CD player and a power amplifier.
In the balanced input amplifier for CD, a balance signal is input to the differential push-pull circuit of the input. In the case of normal unbalanced input, the cold (-) side is connected to ground using the switch on the rear panel.
The input buffer uses a cascode connection to improve the linearity of the input and prevent clipping at large inputs. The cascode push-pull drive stage supplies a drive signal with little distortion to the output stage to realize a low 歪広 dynamic range and improve the out-of-band characteristics, especially in the ultra-high frequency range.
Since the gain of some power amplifiers is insufficient, a gain of 6 dB is provided.

The line amplifier system is equipped with recording and playback functions such as tape monitor, tape copy switch, -20dB attenuator, mode switch, compensator, subsonic filter, balance control, etc.
The line unit amplifier basically has the same configuration as the CD-only amplifier, with the cold input connected to ground.

To avoid routing the signal path for functions such as input switching and tape monitoring, a logic relay control by relay is adopted.
The relay uses a sealed type relay developed especially for audio equipment. The contact is a crossbar twin system with high quality, low contact resistance and high durability.

The power supply consists of a dedicated rectifier circuit supplied by a transformer winding dedicated to the left and right channels, and four filter capacitors of 10,000 μ F are required to obtain good DC voltage.
In order to make the power supply even more pure and powerful, we have adopted a multiple power supply system in which a constant voltage power supply is installed in each unit amplifier. The constant voltage power supply is located close to the unit amplifier to keep the power supply impedance low.

Natural Persimmon sideboards are installed on both sides.

Model Rating

Type	Stereo Preamplifier
& lt ; CD Series & gt ;
Frequency Response	1.0 Hz to 400,000 Hz + 0 -3.0 dB 20 Hz ~ 20,000 Hz + 0 -0.2 dB
Total Harmonic Distortion Factor	0.005%
Input Sensitivity / Impedance	Balanced input : 1.0V/40k Ω Unbalanced input : 1.0V/20k Ω
Rated Output / Impedance	Balanced output : 4.0V/50 Ω Unbalanced output : 2.0V/1 Ω
Headphone jack	Applicable Impedance : 4 Ω ~ 100 Ω
Gain	Balanced input to balanced output : 12 dB Balanced input → unbalanced output : 6 dB Unbalanced input → balanced output : 12 dB Unbalanced input → unbalanced output : 6 dB
SN ratio and input conversion noise	At rated input (input short / A-corrected) : 108 dB Input conversion noise (input short, A-corrected) : -108dBV EIA S/N:97dB
Maximum Power Level	Balanced power : 10 v Unbalanced output : 5 v
Maximum Input Level	Balanced input : 10 v Unbalanced input : 8 v
Minimum Load Impedance	Balanced output : 600 Ω Unbalanced output : 1k Ω Tape Rec : 10k Ω
Attenuator	-20dB
& lt ; Line series & gt ;
Frequency Response	1.0 Hz to 500,000 Hz + 0 -3.0 dB 20 Hz ~ 20,000 Hz + 0 -0.2 dB
Total Harmonic Distortion Factor	0.0055%
Input Sensitivity / Impedance	200mV/20k Ω
Rated Output / Impedance	Balanced output : 4.0V/50 Ω Unbalanced output : 2.0V/1 Ω
Headphone jack	Applicable Impedance : 4 Ω ~ 100 Ω
Gain	Balanced power : 26 dB Unbalanced output : 20 dB
SN ratio and input conversion noise	At rated input (input short, A-correction) : 110 dB Input conversion noise (input short, A-correction) : -128dBV EIA S/N:94dB
Maximum Power Level	Balanced power : 10 v Unbalanced output : 5 v
Minimum Load Impedance	Balanced output : 600 Ω Unbalanced output : 1k Ω Tape Rec : 10k Ω
Attenuator	-20dB
Loudness Compensator (volume control -30dB)	1:+3dB(100Hz) 2 : + 8 dB at 100 Hz, + 6 dB at 20 kHz
Subsonic Filter	10 Hz, -12dB/oct
& lt ; General & gt ;
Semiconductors used	Transistors : 110 FET : 54 IC : 12 pcs Diode : 79
Power Supply	100 VAC / 117 V / 220 V / 240 V, 50Hz/60Hz
Power Consumption	40W
External Dimensions	475 mm wide x 135 mm high x 373 mm deep
Weight	11kg