DENON TU-400
¥ 29,800 (around 1986)
Commentary
FM/AM tuner pursuing the theme of quality and usability.
It is based on a digital synthesizer method that allows easy channel selection and accurate tuning accuracy, and is equipped with a random 16-station preset function to sufficiently cover areas with a large number of receiving stations.
The memory is equipped with a memory backup function that keeps the contents of the memory for about one month after power is turned off without using batteries.
The memory mechanism employs a "4-way tuning mechanism" that fully applies the features of the digital system to improve usability and practicability.
One touch random preset tuning allows you to directly call up the desired station from among the 16 stored stations without switching between FM and AM.
Auto tuning automatically finds and tunes radio waves using autoscan.
Manual scanning is also available.
When the power is turned on, the station is automatically selected to the last station that received the signal.
In order to receive FM radio waves with high precision, we have adopted a quartz lock synthesizer system that synchronizes with the precision of the crystal oscillation according to the frequency arrangement of the broadcasting station.
The comparison frequency of the PLL is set to 25 Hz, which is outside of the audible band, and the SN ratio is improved by eliminating beat and noise in the audio band by adopting a static control method that eliminates noise from the frequency display circuit, etc. This realizes high basic performance.
For the front end part, the analog type uses a varactor diode equivalent to 3 circuits, and J-FET is used for the input part.
The IF stage employs a ceramic filter with constant amplitude and constant delay characteristics.
The AM section employs a 2-stage 3-terminal high-selectivity ceramic filter and a 1-stage coil-type filter that eliminates 9 khz beat interference, and a low-impedance loop antenna that is resistant to electric-field noise from fluorescent lamps.
Model Rating
| Type | FM/AM Tuner |
| <FM Part> | |
| Receiving frequency | 76 to 90 MHz |
| Intermediate frequency | 10.7MHz |
| Antenna terminal | Terminal type 75 Ω unbalanced, 300 Ω balanced |
| Practical sensitivity | 11.2dBf |
| SN ratio 50 dB sensitivity | stereo:38.5dBf mono:21.6dBf |
| Execution selectivity | 50 dB (± 400 kHz) |
| Capture ratio | 1.5dB |
| IF interference ratio | 85dB |
| Image interference ratio | 70dB |
| AM suppression ratio | 50dB |
| Muting operating limit level Stereo automatic switching operation level |
-94.8dB(mW) |
| Frequency characteristic | 20 Hz to 15 kHz, + 0.2 -1.5 dB |
| Corrected SN ratio | stereo:75dB mono:80dB |
| Total harmonic distortion rate (1 kHz) | Stereo : 0.15% at 90% modulation Mono : 0.08% at 100% modulation |
| Separability | 40dB(1kHz) |
| Output level | 0.6 v (at 100% modulation) |
| <AM Department> | |
| Receiving frequency | 522 to 1,629 kHz |
| Intermediate frequency | 450kHz |
| Antenna terminal | Terminal type (loop antenna included) |
| Practical sensitivity | 18 μ V (300 μ V/m) |
| One signal selectivity | 35 dB (± 9 kHz) |
| IF interference ratio | 60dB |
| Image interference ratio | 45dB |
| Signal-to-noise ratio | 52dB |
| Total harmonic distortion factor | Not more than 0.6% |
| Output level | 0.2 V at 30% modulation |
| <General> | |
| Power consumption | 7W |
| Pwer | 100 VAC, 50Hz/60Hz |
| External Dimensions (including legs, knobs, terminals) | Width 434x Height 72x Depth 281 mm |
| Weight | 3.2kg |