DENON PMA-232

Commentary

A pre-main amplifier designed with an emphasis on transmission characteristics.

In the power amplifier section, all stages are directly connected DC amplifier configuration using discrete transistors. In the output stage, a newly developed 60W class epitaxial planar type fully symmetrical power transistor with little minority carrier accumulation effect and little switching distortion is adopted. The transistor used in the output stage does not change the finish condition between NPN and PNP, and has more reliability due to the symmetry.
In addition, a large radiator with high heat radiation effect, a power supply circuit with large current capacity, and a differential amplifier with excellent DC balance are used to expand the transmission frequency band and to reduce low and high frequency distortion.

The equalizer section employs a 3-stage direct-coupled E-E feedback type with a low-noise, high-voltage NPN transistor. In particular, a transistor with extremely high collector loss is used for the emitter follower of the final stage. As a result, the maximum output voltage of the equalizer amplifier is flattened to a high frequency range of 20 kHz. As a result, the allowable input of 10 kHz or higher, which had previously been problematic, is greatly improved.
By using a carefully selected equalizer element, the RIAA deviation is kept within + 0. 2-0. 3 dB, making the total response of recording / reproducing flat.

The tone circuit uses an NFB method with an emitter follower at the front stage.
The Bass/Treble control uses a system that allows automatic defeat at the center point to flatten the transmission characteristics when the tone is flat.

The speaker is protected by using a protective circuit with fast response speed.
In addition, a detection circuit is provided to protect the power transistor.

Equipped with a low filter.

The speaker terminal has a screw-type structure to ensure reliable contact and reduce contact resistance.

The power supply, filter and monitor switch use a new slide system.

It has a unified design with the TU-332 FM tuner.

Model Rating

Type	Pre-main amplifier
Power Amplifier Unit
Circuit system	DC-DC pure complimentary service OCL circuit
Dynamic Output (IHF)	90W + 90W (4 Ω) 55W + 55W (8 Ω)
Rated Output (Both Channels Driven, Sine Wave Continuous Output)	1 kHz : 50W + 50W (4 Ω) 40W + 40W (8 Ω) 20 Hz to 20 kHz : 40W + 40W (4 Ω) 35W + 35W (8 Ω)
Total harmonic distortion factor	0.03% or Less (1 kHz, Rated Output) 0.08% or Less (2kHz/20kHz, Rated Output)
Intermodulation distortion factor (60 hz : 7 khz = 4 : 1)	0.1% or Less (at Rated Output)
Output Bandwidth (IHF, both channel drives)	5 Hz to 45 kHz
Transmission frequency characteristic	5 Hz ~ 200 kHz + 0 -1dB
Output impedance	0.16 Ω or less
Output terminal	Speaker A/B : 4 Ω ~ 16 Ω Headphone : 4 Ω ~ 16 Ω
Preamplifier Section
Circuit system	Equalizer amplifier section : 3-stage NPN transistor directly connected E-E negative feedback type
Input Sensitivity / Impedance	Phono : 2.3mV/50k Ω Tuner, Aux, Tape : 140mV/80k Ω
Phono maximum allowable input	200mVrms(1kHz)
Rated output (Rec out output level)	Phono:140mV
Maximum power output	13 Vpeak or more
Total harmonic distortion factor	0.03% or Less (at Rated)
RIAA deviation	20 Hz ~ 20 kHz + 0.25 -0.2 dB
Tone control	Bass : + 7.5 -5dB at 100 Hz, 2.5 dB step Treble : + 7.5 -5dB at 10 kHz, 2.5 dB step
Frequency characteristic	7 Hz ~ 125 kHz (Tone Amplifier, Tone Defeat)
Filter characteristic	Low Filter : 30 Hz, 12dB/oct.
<General>
Frequency characteristic	Phono-Speaker : 20 Hz to 20 kHz + 0.25 -0.4 dB Aux-Speaker : 20 Hz ~ 20 kHz + 0 -0.3 dB
Total harmonic distortion factor	Phono-Speaker : 0.1% or less (20 Hz to 20 kHz)
SN ratio (IHF-A, input short circuit)	Phono : 75 dB or more Tuner, Aux, Tape PB : 85 dB or more
Channel separation	Phono-Speaker : 70 dB or more (1 kHz) 55 dB or More (20 Hz to 20 kHz)
Power outlet	Switched : 1 system Unswitched : 1 line
Pwer	100 VAC, 50Hz/60Hz
Power consumption	100W (Electrical Appliance and Material Control Law)
External dimensions	Width 396x Height 147x Depth 281 mm
Weight	9kg