Audio Database

PMA-2000III
Commentary

A pre-main amplifier for next-generation audio by improving the PMA 2000 II.

UHC-MOS, a high-current amplifier, is used for the output stage. The UHC single push-pull circuit realizes both fine expressive power and high power.

By reviewing each of the volume circuit, tone circuit and power amplifier circuit, the upper limit of frequency characteristics in actual use has been improved to 100 kHz. Furthermore, by improving the volume circuit, noise generated in the amplifier in actual use is suppressed, and resolution corresponding to next generation audio is obtained.

Twin transformer parallel connection is adopted to improve the characteristics of magnetic circuit and winding circuit, and L. C. (Leakage Canceling) mounting method is adopted to cancel the influence of magnetism to each other to reduce leakage flux of power transformer which is a source of noise in amplifier.
In addition, by adopting new elastic rubber in the floating structure combining special rubber, special resin, and steel plate, the floating effect is further enhanced and adverse effects caused by the vibration of the transformer are prevented.

The power supply is equipped with a Schottky barrier diode developed for high-frequency rectification. High-speed operation with low-noise and high-current characteristics enables low-noise reproduction.
In addition, by installing a power transformer with significantly reduced operating resistance and a combination of a high-capacity electrolytic capacitor and a capacitor with a different frequency, the circuit can supply power with sufficient margin over the entire range of the reproduction frequency.

The Precision Signal Ground circuit is installed to reduce the inflow of noise current such as constant current circuit to the ground circuit which is the reference point of signal amplification.

Precision Mechanical Ground structure is adopted, and by attaching the radiator dumped by elastic rubber and radiator stabilizer directly close to the FOOT, other vibration such as power transformer is reduced and interference of vibration path is suppressed.
In addition, anti-vibration measures such as a top cover with anti-vibration measures and a volume knob with a high mass to suppress vibration are provided.

In order to suppress the deterioration of sound quality due to interference between circuits and inflow of noise, the power amplifier block is made into a twin monaural configuration with independent left and right power amplifier blocks. In addition, circuits with different signal levels are separated, and a 6-block structure with complete shielding is adopted.

The speaker terminal is gold-plated with brass machined parts to reduce transmission loss. The hole diameter of the clamp section is φ 6 mm, making it compatible with very thick speaker cables.
There are two speaker terminals that can be connected by bi-wiring.

The phono equalizer uses a discrete first stage circuit with a low-noise FET and a dedicated stabilizing power supply for the phono equalizer for higher sound quality.
Both MM and MC cartridges can be used by changing the switch.

Pre-out terminal is mounted.

It uses carefully selected parts such as Silmic II electrolytic capacitor, power radiator with excellent heat radiation effect, OFC internal wiring material, inert gas sealed relay, high-sound quality carbon resistance, etc.

The power cord is detachable.

Model Rating
Type Pre-main amplifier
Power Amplifier Unit
Rated output (both channel drive
CD → SP OUT)
80W + 80W (8 ohm, 20 hz to 20 khz, THD 0.07%)
160W + 160W (4 ω, 1 khz, 0.7% THD)
Total harmonic distortion factor 0.01% (Rated Output -3dB, 1 khz, 8 Ω)
Speaker output terminal Speaker AORb : 4 Ω ~ 16 Ω
Speaker A + B : 8 Ω ~ 16 Ω
Bi-wiring load : 4 Ω ~ 16 Ω
Preamplifier Section
Equalizer amplifier output Rec out:150mV
Input Sensitivity / Impedance Phono MM : 2.5mV/47k Ω
Phono MC : 0.2mV/100 Ω
Line : 140mV/70k Ω (source direct off)
140mV/30k Ω (Source Direct On)
RIAA deviation Phono : 20 Hz to 20 kHz ± 0.5 dB
Pre-out output 1 V (CD, etc. line system input, when input signal is 100 mV)
<General>
Frequency characteristic 5 Hz ~ 100 kHz + 0 -3dB
Signal-to-noise ratio (A network
Input terminal short circuit)
Phono MM : 91 dB (at 5 mV input)
Phono MC : 76 dB (at 0.5 mV input)
Line:110dB
Tone control Bass : ± 8 dB (100 Hz)
Treble : ± 8 dB (10 kHz)
Power outlet Switched : 2 systems, total capacity 120W
Unswitched : 1 line, 240W capacity
Power supply voltage 100 VAC, 50Hz/60Hz
Power consumption 275W
External Dimensions (including legs, knobs, terminals) Width 434x Height 180x Depth 478 mm
Weight 22.0kg