DENON PMA-2000IV

Commentary

As the 4th generation of the PMA 2000 series, this pre-main amplifier was created with further improvements.

UHC (Ultra High Current) -MOS is used as the output element. This element is an amplifying element of the smallest unit and has a current supply capability 3 to 10 times that of the normal one. It is composed of a single push-pull circuit to achieve both expressive power and high power.

The power supply section uses a High Current Dynamic power supply circuit with a newly developed block capacitor for audio equipment. A high-current Schottky barrier diode and a newly developed block electrolytic capacitor for rectification enable a stable current supply over the entire band.

By connecting two transformers in parallel, the electrical and magnetic characteristics of the power transformer are greatly improved, and by using the L. C. (Leakage Canceling) mounting method, which cancels the influence of the magnetism of each other, the leakage flux, which is a source of noise in the amplifier, is reduced.
The transformer is also mounted with a combination of special resin and rubber vibration isolator to enhance the floating effect and eliminate the effect on sound quality.

To support next-generation audio, the volume circuit, tone circuit, and power amplifier circuit were reviewed and the upper limit of the reproduction frequency in actual use was set to 100 kHz.

Built-in pre-out terminal and power direct input terminal.
With the Power Direct Input jack, you can select Power Direct with the front panel selector by switching the switch on the back panel. In other positions, it operates as a pre-main amplifier.
A carefully selected relay is used for the input switching to the power amplifier, and the pre-out terminal is also output from the discrete configuration flat amplifier of the MOS-FET output used in the PRA-S1 to improve the sound quality.

The Precision Signal Ground circuit is installed to reduce the noise that flows into the ground circuit, which is the reference of signal amplification, and to stabilize the ground potential.

In order to prevent interference between each circuit and the inflow of noise, power amplifier blocks are arranged symmetrically in a twin monaural configuration. In addition, shielding is thoroughly done according to the signal level. A 6-block separated structure using black treated steel plate with a thickness of 1.6 mm is used.

The Precision Mechanical Ground structure reduces interference with other vibration sources such as power transformers by attaching a radiator dumped by elastic rubber and radiator stabilizer directly close to the FOOT, and also uses a top cover and volume knob with anti-vibration measures.

The phono equalizer uses a discrete equalizer with a low-noise FET at the first stage, and is stabilized by a dedicated power supply to improve sound quality.
MC cartridges are also supported by switching back panel switches.

Parts such as OFC internal wiring material, inert gas enclosed relay, high sound quality carbon resistance and power radiator with excellent heat radiation effect are adopted.

It uses a large speaker terminal with gold-plated brass machined parts. The hole diameter of the clamp part is φ 6 mm, which is compatible with extra-thick speaker cords.
In addition, two speaker outputs are provided for bi-wiring connection.

Model Rating

Type	Pre-main amplifier
Power Amplifier Unit
Rated Output (Both channel driven, CD → SP out)	80W + 80W (8 ohm, 20 hz to 20 khz, THD 0.07%) 160W + 160W (4 ω, 1 khz, 0.7% THD)
Input Sensitivity / Impedance	Power amp direct : 0.9V/47k Ω
Speaker output terminal	Speaker AORb : 4 Ω ~ 16 Ω Speaker A + B : 8 Ω ~ 16 Ω
Preamplifier Section
Input Sensitivity / Impedance	Phono MM : 2.5mV/47k Ω Phono MC : 0.2mV/100 Ω Line : 135mV/47k Ω (source direct off) 135mV/13k Ω (Source Direct On)
RIAA deviation	20 Hz to 20 kHz ± 0.5 dB
Rated output	Equalizer amplifier output (Rec out) : 150 mV Pre out : 0.9 v (at Line input of 135 mv)
<General>
Frequency characteristic	5 hz to 100 khz -3dB
Total harmonic distortion factor	0.01% (CD → SP out, Rated Output -3dB, 8 Ω, 1 khz)
Signal-to-noise ratio (A network Input short-circuit)	Phono MM : 90 dB at 5 mV input Phono MC : 73 dB (at 0.5 mV input) Line:108dB
Tone control	Bass : ± 8 dB (100 Hz) Treble : ± 8 dB (10 kHz)
Power outlet	Switched : 2 systems, total 120W Unswitched : 1 line, 240W
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	275W
External dimensions	Width 434x Height 180x Depth 478 mm
Weight	23.5kg