TRIO KT-8005
¥ 70,000 (around 1973)
Commentary
This is an FM/AM tuner designed with an emphasis on sound quality, using a proprietary double-switching and de-modulator method.
Multi-section uses double switching and de-modulator system.
In this method, the leakage signal is canceled by making the outputs of the main and auxiliary switching circuits symmetrical and out-of-phase, and adding the output of the quantity switching circuit.
In addition, a phase correction circuit is mounted in front of the auxiliary switching circuit to match the phases of the main signal and the leakage signal. This design prevents adverse effects on the high frequency of the SCA filter and deterioration of the separation caused by the phase difference between the main signal and the auxiliary signal at the IF stage.
A unique buffer amplifier for local oscillation using FET is mounted between the mixing circuit and the local oscillation circuit in the front end section. This has succeeded in separating the mixing circuit and the local oscillation circuit, improving various characteristics at the time of Dainyu power.
In addition, by adopting MOS FET and FM5-series varicon, the circuit design of high frequency amplification stage, frequency mixing stage, and intermediate frequency amplification stage was renewed, and both IHF sensitivity and intermodulation, which were difficult to be compatible, were improved.
The circuit elements used to determine the characteristics of the IF stage include selected high-gain ICs and 8-element ceramic filters to achieve high selectivity.
Frequency number line type varicon is used, and dial scale of equal interval graduation is adopted.
Equipped with a multipath detection mechanism that can be checked using a signal meter.
The waveform can also be observed by connecting the terminal on the back to an oscilloscope.
It uses a signal meter proportional to the electric field strength, so that it can catch the best receiving point that conventional meters could not measure. It can also check the electric field strength at the receiving point and judge the quality of the antenna.
The FM selector is equipped with a Stereo Only position, which allows you to receive only the with a stereo broadcast transmission.
Equipped with FM muting that can be switched to 2 stages.
Micro plug for 75 Ω coaxial cable is mounted.
It is equipped with an LC-type carrier-leak filter developed by a proprietary method, and achieves a carrier-leak suppression almost equal to the SN ratio.
The structure and winding method of the coil have been improved to match the temperature characteristics of the core and the phenolic resin covering the core to realize a coil resistant to changes in temperature.
Equipped with a filter with an attenuation of 50 dB or more at 19 kHz and 34dB/oct-cut at 19 kHz.
In addition, the input / output impedance of the low-pass filter insertion circuit is stabilized to achieve almost flat characteristics in the range of 100 Hz to 10 kHz.
Various characteristics have been improved by installing a 3-row air varicon and AGC in the AM section and a 2-element ceramic filter in the IF stage.
.JPG)
Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| Receiving frequency | 76 MHz to 90 MHz |
| Antenna impedance | 300 Ω equilibrium 75 Ω unbalance |
| Sensitivity | 1.5 μ V/84MHz |
| Chinese arrowhead's slope | 55 dB (3 μ V) 65 dB (10 μ V) 73 dB (50 μ V) |
| Distortion factor | Not more than 0.2% |
| SN ratio (100% modulation, 100 μ V input) | 75dB |
| Capture ratio | 1.0dB |
| Selectivity (IHF) | 100 dB or more |
| Image ratio | 100 dB or More (84 MHz) |
| IF interference ratio | 100 dB or More (84 MHz) |
| AM suppression ratio | 65dB |
| Harmonic spurious response | 110 dB or more |
| Multipath output | 0.15 V (both vertical and horizontal) |
| Multipath impedance | 20k Ω |
| <FM MPX Part> | |
| Separation | 45dB(400Hz) 40 dB (100 Hz to 8 kHz) 35 dB (50 Hz to 15 kHz) |
| Carrier leakage | 65dB |
| Distortion factor | 0.3% |
| Signal-to-noise ratio | 70dB |
| Frequency characteristic | 50 Hz to 15 kHz + 0.2 -1.0 dB 100 Hz to 10 kHz + 0.2 -0.5 dB |
| SCA interference ratio | 65dB |
| <AM Tuner Section> | |
| Receiving frequency | 520 kHz to 1610 kHz |
| Sensitivity | 13 μ V (IHF) 300 μ V/m (bar antenna) |
| Image ratio | 70 dB or more |
| IF interference ratio | 70 dB or more |
| Signal-to-noise ratio | 50dB |
| Selectivity | 40dB |
| Distortion factor | Not more than 0.5% |
| <General> | |
| Rated Output (400 Hz) | FM (100% modulation) : 1.5 V AM (30% modulation) : 0.15 V |
| Output impedance | 100 Ω or less |
| Power supply voltage | 100 VAC / 117 V, 50Hz/60Hz |
| Rated power consumption (Electrical Appliance and Material Control Law) | 20W |
| External dimensions | Width 435x Height 153x Depth 300 mm |
| Weight | 11.3kg |