Audio Database

PMA-580D
Commentary

Pre-main amplifier with built-in D/A converter.

The D/A converter uses the "W Super Linear Converter" system, which has independent left and right channels. This system was developed based on the technology developed in the field of commercial digital (PCM) equipment.
Since there is no conversion error (distortion) at large input, and two pairs of D/A converters are used, channel separation is excellent and there is no time difference between left and right channels.
In addition, a 4 x oversampling digital filter has been adopted to improve linear phase characteristics.

The coaxial digital input is mounted Route 3 and also equipped with an optical digital input.
A digital audio multi-interface demodulation circuit with a digital input selector based on a high-speed C-MOS logic circuit automatically recognizes differences in sampling frequency and performs D/A conversion.

Shield between the digital audio interface demodulation circuit and the D/A converter circuit.
The interface circuit is equipped with a dedicated power supply independent from the secondary side of the transformer to prevent bypassing of the power supply circuit for digital signals, which is a source of noise from analog signals.
In addition, by covering it with a shield case that is also used to prevent vibration of the chassis and circuit board, digital signals are prevented from leaking to the analog section.

The power amplifier section is designed to increase power and simplify the circuit.
A high-speed, large-capacity transistor is used in the final stage in a single push-pull operation. A low-noise, low-distortion operational amplifier is used in the first stage of the voltage amplification stage, and a complimentary service push-pull circuit is used in the second and third stages.

Equipped with a digital direct input switch, the digital signal is converted to an analog signal and then directly connected to the power amplifier, enabling straight playback.
In addition, one of the two speaker terminals (speaker B) uses a direct connection method that does not involve a changeover switch to reduce transmission loss.

The power supply uses a 400 VA rank toroidal transformer and a 8,200 μ Fx4 electrolytic capacitor.

In order to support playback of analog records, an equalizer amplifier composed of low-noise transistor differential amplification at the first stage is mounted.

Audio and digital systems are separated from the power supply via a large heat sink to minimize the impact.

Equipped with a subsonic filter for Phono.

Newly designed reset-type high-speed protection circuit is adopted.

Broadband real-time tone control is adopted.

Model Rating
Type Pre-main amplifier with digital multi-interface
Power Amplifier Unit
Rated Output (20 Hz ~ 20 kHz) 100W + 100W (8 Ω)
120W + 120W (6 Ω)
Input Sensitivity / Impedance CD Input : 150mV/30k Ω
Total harmonic distortion factor 0.005% (20 Hz to 20 kHz, 50W, 8 Ω)
Dynamic Characteristics / Dynamic Power 230W/2 Ω
Output bandwidth 5 Hz to 50 kHz (50W output, 0.5%, 8 Ω)
Line input frequency characteristic 4 Hz ~ 100 kHz + 0 -3dB (output 1W, 8 Ω)
Output impedance 0.1 Ω or less
Output terminal Speaker : AORb : 6 ~ 16 Ω, A + B : 12 ~ 16 Ω
Headphone Jack Maximum Output : 390 mW (8 Ω), 8 ~ 400 Ω Compatible
<Interface / DAC part>
Digital Output Level / Impedance Coaxial : 0.5Vp-p/75 Ω
One standard optical input
Frequency response (0 dB) 5 Hz to 20 kHz ± 0.3 dB
Signal-to-noise ratio (vs. 0 db, 1 khz) 105dB
Dynamic Range (1 kHz) 96dB
Total harmonic distortion factor (0 dB, 1 kHz) 0.003%
Preamplifier Section
Input Sensitivity / Impedance Phono MM : 2.5mV/47k Ω
Phono MC : 0.2mV/100 Ω
CD, Tuner, AUX, Tape1, 2 (PB) : 150mV/30k Ω
Maximum output and rated output 8 v / 150 mv
Total harmonic distortion factor 0.003% (1 kHz, 1 V)
RIAA deviation 20 Hz ~ 100 kHz ± 0.3 dB (MC. IN)
<General>
SN ratio (Audibility compensation A, input short circuit) Phono MM:87dB
Phono MC (at 0.25 mV input) : 70 dB
Line : 108 dB
Tone control characteristics Bass : 100 Hz ± 8 dB
Treble : 10 kHz ± 8 dB
Loudness control characteristic 100 hz + 7 dB, 10 khz + 6 dB
Muting switch -20dB
Power consumption 167W
Pwer 100 VAC, 50Hz/60Hz
External dimensions Width 434x Height 143x Depth 390 mm (including foot, knob, terminal, etc.)
Weight 10.0kg