Audio Database
RA-2040
Commentary

Pre-main amplifier integrating the performance of RC-2000 and RB-2000.

The main amplifier, equalizer amplifier, MC amplifier and flat amplifier are of DC type without the capacitor from the input.
In the first stage of the DC-power amplifier section, a dual-FET with the same characteristics is adopted, and it is combined with a pure complimentary service OCL circuit to realize excellent sound quality. In addition, regarding the drift of the midpoint potential, which is a problem in DC-amplifiers, the power fluctuation is suppressed in each stage, and the pair characteristics are improved to improve stability.

Taking advantage of the good sound quality of class A amplifier, it adopts class AB operation system which can obtain large output.
Normal operation is class A operation, and it is automatically switched to class B operation when a large signal requires a large power.

We have achieved a low distortion rate by focusing on materials and parts as well as printed circuit board design and shielding cord placement.

The power supply section uses a large toroidal core transformer with high efficiency, excellent regulation, and low leakage flux.

As protection circuits, an Electro-Carry Control ASO (Safe Operating Area) circuit and a DC feedback power limit circuit are mounted. The electro-carry control ASO circuit operates as a relay to protect the amplifier transistors and speakers, and the DC feedback power limit circuit operates quickly against overload to protect the transistors.
In addition, the RA 2040 has a special relay and in-rush absorber for the in-rush current at power-on, which is a problem in high-output amplifiers, to improve safety and reliability.

Equipped with an LED-based peak indicator. With 13 LEDs per channel, the power is replaced by digital for quick display.
The indicator display is equipped with a sensitivity switching mechanism (- 20 20 dB) and an OFF switch, it is easy to read even when the volume is low, and the indicator can be turned off when it is not necessary.

Equipped with MC head amplifier.
The head amplifier used in the RA 2040 is a DC type that eliminates the capacitor from the input circuit.
The circuit configuration is a differential-amplification type with an ultra-low noise transistor at the inlet where the input signal is completely symmetric with positive and negative, and a pure complimentary service push-pull type at the outputs.

The equalizer amplifier uses a 2-stage DC differential input circuit with a low-noise FET. The push-pull configuration of the output stage provides excellent characteristics.

The switches for the Phono Selector, Recording Selector and Function Selector are installed on the rear panel to minimize the wiring of the shield cord. A flat rod extending from the front panel knob drives the switches on the rear panel.

The MM cartridge can be adjusted in three levels of load impedance and three levels of additional capacitance for a total of nine combinations.

With a built-in recording selector, you can choose the output signal to the tape deck regardless of the sound coming from the speakers.

A DC amplifier is used for the tone control circuit, and a tone defeat switch can be used to cancel the tone circuit and operate as a flat buffer amplifier.
The RA 2040 has two levels of Bass and Treble adjustment for the turnover frequency.

Equipped with a subsonic filter and a supersonic filter.

Uses gold-plated terminals.

The front panel is an EIJ standard rack mount type.

Model Rating
Type Pre-main amplifier
Power Amplifier Unit
Rated Output (Both channel drive) 140W/ch (4 Ω, 1 kHz)
120W/ch (8 Ω, 20 Hz to 20 kHz)
Total harmonic distortion factor 0.01% (20 Hz, 20 Hz to 20 kHz)
Cross modulation distortion factor 0.015% (8 Ω at rated output)
Frequency Characteristics (1W/ch, 8 Ω) DCin : DC ~ 100 kHz + 0 -1dB
AC in : 5 Hz ~ 100 kHz + 0 -1dB
Input Sensitivity / Impedance 1.5V/50k Ω
Damping factor (8 Ω) 65 (20 Hz ~ 20 kHz)
100(1kHz)
S/N ratio (IHF-A network short) 110dB
Crosstalk (10 kHz) 65dB
Equalizer Section
Harmonic distortion factor Phono MAG:0.005%
Phono MC:0.006%
RIAA deviation (20 Hz to 20 kHz) ± 0.3 dB
Input Sensitivity / Impedance Phono1 MAG : 2mV/35, 50, 70k Ω / 0, 100, 200 pF
Phono2 MAG : 2mV/50k Ω
Phono3 mc : 100 μ V/33 Ω
Maximum Allowable Input (1 kHz, 0.5% THD) Phono MAG:400mV
Phono MC:15mV
Preamplifier Section
Harmonic distortion factor 0.008% (20 Hz to 20 kHz at rated output)
Frequency characteristic 4 Hz to 160 kHz
S/N ratio (IHF-A network) Tuner, Aux : 95 dB
Tape monitor:95dB
Residual noise (volume minimum) 6 μ V, 100 dB
Input Sensitivity / Impedance Tuner, Aux : 150mV/50k Ω
Tape monitor : 150mV/50k Ω
Maximum Allowable Input (1 kHz, 0.5% THD) Tuner, Aux : 15 v
Tape monitor:15V
Slew rate 40 V / μ S
Square wave rise time 2 μ S
<Control Characteristics>
Turnover frequency Bass:150Hz/400Hz
Treble:7kHz/2.5kHz
Control Width Bass : ± 5 dB / ± 10 dB
Treble : ± 5 dB / ± 10 dB
Supersonic filter 24 kHz, 12dB/oct.
Subsonic filter 15 Hz, 12dB/oct.
<General>
Maximum Power Consumption 900W
External dimensions Width 482x Height 143x Depth 408 mm
Weight 22kg