DENON TU-332

Commentary

An FM stereo tuner with improved characteristics aimed at an FM tuner with better sound quality.

The front end is equipped with a 4-row varicon dedicated to FM.
In addition, a low-noise dual-gate MOS-FET is used in the RF stage that controls the noise characteristics to enhance the interference rejection capability.

The intermediate frequency amplifier is equipped with a high-gain amplifier stage and a 5-stage limiter that employ highly reliable high-integration ICs to prevent audio quality degradation due to interference.
The combination of a phase-flat (phase-linear) 6-element ceramic filter and an LC circuit ensures a high effective selectivity of 78 dB. The use of carefully selected elements with excellent resistance to temperature and humidity greatly improves drift characteristics.

The MPX circuit employs a PLL circuit based on a high-integration IC to greatly improve the separation characteristics and stereo distortion factor. In particular, the improvement of the nonlinear crosstalk waveform with an emphasis on the audibility of sound provides clearer sound quality with clear sound image localization without distortion.

An LC2-stage low-pass filter is used in the subcarrier elimination circuit to suppress carrier leakage to less than 65 dB.

The intermediate frequency section, stereo demodulation section, and audio frequency section are integrated into one block to reduce the instability caused by wiring.

In addition to the antenna terminal 300 Ω terminal, a 75 Ω F-type connector that can use a coaxial cable is provided.

Equipped with a muting switch.

Equipped with an FM stereo / mono switch.

It has the same design as the pre-main amplifier PMA-232.

Model Rating

Type	FM tuner
Tuner Section
Circuit system	Front end of RF1-stage 4-series varicon using dual gate MOS-FET 2-element Flat Phase Filter 3 IF Stage クォードラチュア detector circuit PLL-MPX Circuit
Receiving frequency range	76 MHz to 90 MHz
Intermediate frequency	10.7MHz
Practical sensitivity (IHF)	1.8 μ V
S/N50dB sensitivity	45 μ V
Effective selectivity (IHF)	78dB
Image interference ratio	90dB(83MHz)
IF interference ratio	90dB
Spurious response	88dB
AM suppression ratio	60dB
Capture Ratio (IHF)	1.2dB
<Audio section>
Frequency characteristic	20 Hz ~ 15 kHz + 0.2 -3dB (with 19 kHz Filter)
Signal-to-noise ratio	mono:75dB stereo:65dB
Total harmonic distortion factor	Mono : 0.1% at 1 kHz, 100% modulation Stereo : 0.15% at 1 kHz, 90% modulation
Stereo separation	45dB(1kHz) 40 dB (100 Hz to 10 kHz)
Output voltage (at 100% modulation)	1V
Output impedance	1.5k Ω
<General>
Antenna input	300 Ω / 75 Ω (F Type)
Attached switch	Power switch Muting High blend switch Function switch (FM Auto-Mono) Tuning
Pwer	100 VAC, 50Hz/60Hz
Power consumption	15W
External dimensions	Width 396x Height 147x Depth 281 mm
Weight	5kg