DENON TU-630

Commentary

FM stereo tuner with built-in monitor amplifier.

The front end section consists of a dual-gate MOS-type FET and a 5-series varicon dedicated to FM.
This FET has excellent high-frequency and noise characteristics, and by using a high-frequency (RF) amplifier stage and mixer stage, it realizes high sensitivity, high S/N ratio, and excellent interference rejection capability.

The IF amplifier achieves both transmission characteristics and separation characteristics between stations by switching between wide-band and narrow-band in two stages. Wide-band consists of two linear phase ceramic filters, while narrow-band consists of five ceramic filters.

The FM detection circuit employs a newly developed quadrature detection IC with greatly improved linearity of phase characteristics. Compared with conventional parts, this circuit reduces distortion by half and improves the S/N ratio by 6 dB.
Combined with the linear-phase ceramic filter used in the intermediate frequency amplifier, it enables excellent stereo reproduction.

The newly developed PLL IC for MPX is used in the MPX circuit.
This MPX circuit uses a 19 kHz pilot signal for demodulation into a stereo signal, but this signal is unnecessary as an audio signal and is equipped with a pilot canceler circuit developed to remove this unnecessary component.
In addition, the S/N ratio has been improved by using a new IC with a built-in 100% NFB circuit to reduce the distortion in the stereo demodulation section.

It has a built-in servo-lock circuit, and by activating the servo-lock after tuning, highly accurate and stable medical examination is possible.

Signal tuning display using LED is adopted.
Three LEDs are used for the tuning display. When the tuning is performed close to the desired station, the right or left AKAI LED lights up corresponding to the frequency shift, and when the tuning state is entered, the green LED in the center lights up.
In this ON the servo lock in this state, the tuning is accurately held.

The signal level of the antenna input is displayed by five LEDs, and the number of LEDs lit varies depending on the signal strength.

Equipped with a full-scale monitor amplifier using IC, and low impedance / high impedance headphones can be used.

Built-in oscillator for recording level check.

Multi-path detection terminal is mounted.

Long linear scale with effective length of 214 mm is adopted.

Model Rating

Type	FM tuner
FM Tuner Section
Receiving frequency	76 MHz to 90 MHz
Antenna terminal	75 Ω (PAL Type) 300 Ω (Terminal Type)
Practical sensitivity	1.7 μ V/9.8 dBf
S/N50dB sensitivity	Stereo : 30 μ V/34.7 dBf Mono : 3.3 μ V/15.6 dBf * μ V at 300 Ω, 0 dBf at 10-15W (New IHF)
Image interference ratio	110dB
IF interference ratio	105dB(83MHz)
Spurious response	110dB(83MHz)
AM suppression ratio	60dB(IHF)
Effective selectivity	Wide : 35 dB (± 300 kHz) Narrow : 80 dB (± 400 kHz)
Capture ratio	wide:1.0dB narrow:1.5dB
Frequency characteristic	20 Hz to 15 kHz + 0.2 -1.5 dB
Signal-to-noise ratio	mono:82dB stereo:79dB
Total harmonic distortion factor	mono (at 100% modulation) wide: narrow: 0.04%(100Hz) 0.03%(1kHz) 0.07%(10kHz) 0.15%(100Hz) 0.1%(1kHz) 0.15%(10kHz) stereo (at 90% modulation) wide: narrow: 0.09%(100Hz) 0.06%(1kHz) 0.15%(10kHz) 0.15%(100Hz) 0.12%(1kHz) 0.3%(10kHz)
Stereo separation	wide: narrow: 50dB(100Hz) 55dB(1kHz) 45dB(10kHz) 45dB(100Hz) 50dB(1kHz) 50dB(10kHz)
Muting action level	20 dB at μ V, 300 Ω
Multipath Output / Adaptive Load	Vertical : 50 mV (equivalent to AM30% modulation) / 10k Ω or more Horizontal : 350 mv (equivalent to 100% modulation of FM) / 10k Ω or more
Tuner output / compatible load	1 V Fixed (at 100% Modulation) / 10k Ω or More
Accessory function	High blend
Level check Signal
Frequency	440 Hz sine wave
Output level	0.5 v (equivalent to 50% modulation)
Monitor Amplifier Section
Rated output	3W+3W(1kHz)
Output terminal	Speaker load : 8 Ω ~ 16 Ω Headphones : stereo headphones
<Tuning instruction>
Tuning	Lighting display with 3 LEDs
Signal	Lighting indication with 5 LEDs Lights up from at least 20 dB (μ V, 300 Ω) to 60 dB (μ V, 300 Ω) every 10 dB
<General>
Power supply voltage	100 VAC, 50Hz/60Hz
Power consumption	24W
External dimensions	Width 434x Height 98.5x Depth 364 mm (Including Knob, Foot and Terminal)
Weight	7.8kg