Audio Database

This monaural power amplifier was completed over a long period of time without any compromise with the aim of further improving the quality of reproduced music.

The use of a monaural power amplifier reduces interference between the left and right channels while keeping the weight and size within a range that can be handled by one person.

The circuit configuration is based on an active element with excellent high-frequency characteristics, and all amplification stages are composed of symmetric push-pull. By applying a small amount of NFB, excellent rise characteristics, linearity and stability are achieved.
This prevents the occurrence of TIM distortion and provides low distortion output even at full power.
In addition, in order to achieve sound quality with less coloration, the condenser inside the NFB loop has been removed to create a DC amplifier configuration.

A large transformer and a 22,000 μ Fx2 filter capacitor apply a high voltage to the power supply section obtain a large energy of 152 joules (120 joules for the P-300 type).
This greatly improves the low-frequency output characteristics.

The output meter uses a logarithmic compression type that can read directly from 3 mW to 300W continuously.
This meter can switch both peak indication and volume indication with a switch.

It is equipped with a subsonic filter to cut unwanted ultra-low frequency noise.

It is equipped with a 25-contact rotary switch that can adjust the volume by 1 dB step up to -20dB, and -23dB, -26dB, -30dB and - ∞.

It is a 19-inch standard rack-mount type with a canon input for use as a studio monitor or hall PA.

A separately sold forced-air cooling fan can be installed for setting in a place where heat radiation effect is extremely bad or for continuous use with large output for a long period of time.

Model Rating
Type Monaural power amplifier
Rated output
(20 Hz to 20 kHz, Distortion Factor 0.03% or Less)
450W (4 Ω)
300W (8 Ω)
150W (16 Ω)
Total harmonic distortion rate (20 Hz to 20 kHz) 0.03% or Less (Rated Output)
0.01% or Less (at -3dB Output)
0.05% or Less (at 50 mW Output)
IM distortion factor 0.01% or Less (at Rated Output)
Frequency response (8 Ω load) 20 Hz ~ 20 kHz + 0 -0.2 dB at Rated Output
2 Hz ~ 150 kHz + 0 -3.0 dB at 1W Output
Damping factor (8 Ω load) 120(40Hz)
Input Sensitivity / Impedance 2.0V/100k Ω
S/N ratio (input short, IFF-A) 115 dB (at rated output)
Subsonic filter 17 Hz, 18dB/oct.
Output meter Logarithmic compression type
Continuous direct reading from -50dB (3 mW) to + 3 dB (600W)
With Peak Level and Volume Level Selector Switch
Semiconductor used Transistor : 47
IC : 3
Diode : 51 Units
Power supply voltage AC100V/117V/220V/240V, 50Hz/60Hz
Power consumption No input : 65W
4 Ω load rated output : 800W
8 Ω load rated output : 540W
External dimensions Width 482x Height 170x Depth 345 mm
Weight 27kg
Sold Separately Accessories Set (With Fan) O-81 (¥ 8,000)
Remarks Standard Rack (19 inch) attachable
Rack mount pitch : 100 mm (4 inch)
Rack inner diameter (horizontal) : 430 mm (16 15/16inch) or more