Audio Database

This is a control amplifier that Accuphase has developed by combining the technologies it has developed over many years.
It is equipped with a head amplifier for MC cartridge and a full-fledged headphone amplifier as well as various sound adjustment functions.

A fully symmetrical push-pull circuit is used for all stages, from the head amplifier inlet to the final output stage, and even the headphone amplifier.
In addition, the capacitor for DC cut is removed from the NF loop of all unit amplifiers for DC method, and coloring for sound quality is eliminated. In addition, the input capacitor is removed for ICL method.

MOS FET is used for output stage of equalizer amplifier and high-level amplifier to improve various characteristics.

To prevent the impedance of the power supply from increasing, each unit amplifier is equipped with a dedicated constant-voltage power supply on the printed circuit board of each unit amplifier. The power supply is adjusted to the ideal power supply and the power supply, and excellent stability and characteristics are obtained.

In order to operate as a DC amplifier even when tone control is active, the DC servo system is used to suppress DC drift to almost zero.
The feature of this servo system is that it controls the constant current load of the input buffer and does not directly control the system through which the signal flows, thus minimizing the influence of the servo system on the sound quality.
In addition, a feedback prevention circuit is inserted to solve the problem that the high-frequency distortion characteristic deteriorates due to the feedback capacitance of the input buffer circuit.

The equalizer amplifier uses a MOS FET for the output to drive a class A large current to lower the output impedance. At the same time, the S/N ratio is improved by reducing the impedance of the NF loop. A feedback prevention circuit is also inserted in this amplifier to prevent the deterioration of high-frequency distortion due to the feedback capacitance of the input circuit.

The head amplifier consists of a symmetrical push-pull circuit, and the input is directly connected to reproduce more detail with high transparency.
For noise, which is a problem because the signal level is small, an ultra-low noise transistor is used to obtain S/N close to the ideal limit value.

The headphone amplifier uses a dedicated DC-configuration A-class pure con direct connection amplifier.

The tone control function has been expanded to include a turnover changeover switch.
This allows you to select 200 or 500 Hz for BASS and 2 or 7 kHz for TREBLE.
The variable method is performed with an 11-contact rotary switch, and the change of the step can be kept accurately.
It also has a tone control ON/OFF switch.

It is equipped with a Loudness Compensator switch that adjusts the energy balance by correcting the audibility of low sound playback. Three curves can be selected depending on the playback level and the characteristics of the listening room.
COMP1 is + 6 dB (50 Hz), COMP2 is + 9 dB (50 Hz), and COMP3 is + 10 dB (50 Hz) and + 6 dB (20 kHz) (volume adjustment -30dB)

Equipped with 17 Hz, 12dB/oct subsonic filter.
The input active element of the high-level amplifier is utilized to emphasize sound quality when it is ON, and an active filter is formed only by adding CR without adding any active element.
This reduces sound quality and S/N degradation.

Two tape recorders, etc. can be connected, and by using an independent copy switch, it is possible to listen to other program listening to other program sources.
The recording output ON/OFF switch is also useful for cutting unnecessary programs. This switch is also useful for preventing distortion caused by the input circuit acting as a load on the control amplifier when the power of a tape recorder is OFF.

These include a -20dB attenuator switch, a mode switch, and a switch that turns off the recording output circuit when the tape recorder is not in use and prevents distortion.

Cabinet with natural rosewood finish is sold separately.
(The cabinet in the photo.)

Model Rating
Type Stereo Control Center
Frequency Response (New IHF) 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 (new IHF, THD + N) 0.005% or less (20 Hz to 20000 Hz)
Input Sensitivity / Input Impedance
(Rated / New IHF)
DISC (HEAD AMP : OFF) : 2.5mV/0.96mV/100, 47k, 82k, 150k Ω
DISC (HEAD AMP : ON) : 0.125mV/0.05mV/100 Ω
AUX, Tuner, Tape, Play : 160mV/62mV/47k Ω
Rated Output / Output Impedance Output : 1.3V/20 Ω
Tape Rec : 160mV/200 Ω
Headphones Output impedance : 0.3 Ω
Output (8 Ω load) : 0.25W, 1 kHz
Strain (THD + N) : 0.01%
S/N (A-corrected) / input conversion noise
Input short at rated input
Tuner, AUX, Tape Play : 112dB -128dBV
Tuner, AUX, Tape Play : 92dB
Maximum Power Level 8.0 v or more
Strain (THD + N) : 0.005% (20 Hz to 20000 Hz)
Disk Max Input
HEAD AMP OFF: 300 mVrms, 1 kHz
Strain (THD + N) : 0.005%
HEAD AMP ON: 15 mVrms, 1 kHz
Strain (THD + N) : 0.005%
Minimum Load Impedance Outputs : 1k Ω
Tape Rec : 10k Ω
from Tuner, AUX, Tape Play
Tape Rec: 0dB
Outputs: 18dB
HeadPhones: 18dB
Tape Rec: 36dB
Outputs: 54dB
HeadPhones: 54dB
(+ 26 dB at DISC input HEAD AMP ON)
Tone Controls Stepped with 11-contact rotary switch
Bass 500 Hz : ± 10 dB (100 Hz)
200 Hz : ± 10 dB (50 Hz)
2 dB step
2 dB steps
Treble 2 kHz : ± 10 dB (10 kHz)
7 kHz : ± 10 dB (50 kHz)
2 dB step
2 dB steps
Loudness Compensator COMP1:+6dB(50Hz)
COMP3 : + 10 dB (50 Hz), + 6 dB (20 kHz)
(volume control, -30dB)
Subsonic Filter 17 Hz, -12dB/oct
Attenuator -20dB
Semiconductors used 85 tr, 16 fet, 5 ic, 22 di
Power Supply 100 v, 117 v, 220 v, 240V/50Hz, 60 hz
Power Consumption 35W
External Dimensions Width 445x Height 128 (including legs) x Depth 370 mm
Weight 10.0kg
Sold Separately Wood Cabinet A-9(¥15,000)