DENON PMA-S10III

Commentary

This is a pre-main amplifier that inherits the basic configuration of the PMA-S10II and improves sound quality by adding more materials.

The output stage uses a high-current amplifier UHC-MOS with a peak current of 120A, which is three to ten times the current supply capability of the conventional amplifier. This UHC-MOS is used in a single push-pull circuit to achieve both high power and fine expression.

The power transformer employs a toroidal transformer with a large magnetic circuit. The design with a wide dynamic range for the magnetic saturation region improves the ability to follow music signals. In addition, to solve the problem of vibration, which was a weak point of the toroidal transformer, the S. B. (Stable Based) fixing method using an aluminum sand mold case is adopted.
In addition, the windings of the power supply for the voltage amplification stage and phono equalizer are independent, and the transformer of the power supply for the control circuit that controls the signal relay is also independent, so that mutual interference between each circuit is suppressed.

By reviewing the volume circuit, tone circuit, and power amplifier circuit, the upper limit of frequency characteristics in actual use has been improved to 100 kHz, and by improving the volume circuit, noise generated in the amplifier in actual use is suppressed.

The rectifier circuit is equipped with a Schottky barrier diode in parallel connection, which was developed for high-frequency rectification for the first time as a power amplifier power supply of a mass-production model. Low-noise characteristics due to high-speed operation and excellent high-current characteristics enable low-noise, low-loss and high-speed power supply circuits.
In addition, by combining an electrolytic capacitor using a low-impedance electrode foil with a capacitor with different frequency characteristics, a stable current supply is realized in the entire bandwidth of the reproduction frequency.
In addition, extremely thick OFC wiring material is used for wiring from the output of the power transformer to the output stage of the power amplifier.

In order to suppress the deterioration of sound quality due to interference between circuits and inflow of noise, the power amplifier block is independent on the left and right in twin monaural configuration. In addition, circuits with different signal levels are different signal levels are separated, and a 6-block structure with complete shielding is adopted.
In addition, to reduce noise caused by vibration, the chassis is made of 1.6 mm thick steel plate coated with black paint to increase rigidity and uniform temperature inside the chassis.
The insulator uses a sintered alloy insulator that converts vibration into heat and reduces vibration on the chassis. In addition, the effect is enhanced by attaching a material with high vibration absorbing properties.
In addition, various measures against vibration have been taken, such as improving the mounting method of the power amplifier circuit and power radiator, and making the top surface of the top cover fixed at six points.

Transmission loss is reduced by gold-plating the brass machined parts of the speaker terminal, and the hole diameter of the clamp section is enlarged to φ 6 mm to accommodate very thick speaker cables.
There are two speaker terminals that can be connected by bi-wiring.

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.

It is equipped with a phono equalizer that uses a discrete first stage circuit with a low-noise FET. The tuning power supply for the phono equalizer improves the sound quality.
In addition, it is compatible with both MM and MC cartridges by switching the switch.

It employs a 40-inch 4-channel volume, a large machined gold-plated pin jack, OFC internal wiring material, an inert gas-filled relay, a high-quality sound condenser, a detachable extra-thick power cord, and a new Silmic II electrolytic II electrolytic capacitor.

Model Rating

Type	Pre-main amplifier
Power Amplifier Unit
Rated output (Both channel drive, CD → SP out)	100W + 100W (8 Ω, 20 Hz to 20 kHz, THD 0.07%) 200W + 200W (4 ω, 1 khz, 0.7% THD)
Total harmonic distortion factor	0.01% (8 Ω at -3dB rated output, 1 kHz)
Output terminal	Speaker AORb : 4 Ω ~ 16 Ω Speaker A + B : 8 Ω ~ 16 Ω Biwiring : 4 Ω ~ 16 Ω
Preamplifier Section
Input Sensitivity / Impedance	Line : 150mV/47k Ω (source direct off) 150mV/15k Ω (Source Direct On) Phono MM : 2.5mV/47k Ω Phono MC : 0.2mV/100 Ω
Equalizer amplifier output	Rec out:150mV
RIAA deviation	Phono MM : 20 Hz to 20 kHz ± 0.5 dB Phono MC : 30 Hz to 20 kHz ± 0.5 dB
<General>
Frequency characteristic	5 Hz ~ 100 kHz + 0 -3dB
Signal-to-noise ratio (A network, input short circuit)	Line:110dB Phono MM : 91 dB (at 5 mV input) Phono MC : 76 dB (at 0.5 mV input)
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	300W
External Dimensions (including legs, knobs, terminals)	Width 434x Height 181x Depth 485 mm
Weight	28kg