Accuphase T-103
¥ 150,000 (released in January 1979)
Commentary
A hybrid FM tuner that combines the advantages of a highly complete varicon system and a digital display capable of accurate frequency display.
Instead of the horizontal dial type, a crystal oscillator and a counter circuit are used for digital display at every 100 kHz. However, the receiving frequency is continuously variable and the display is rounded off to the nearest 0.01 MHz.
The accurate tuning point is determined by a center-directed tuning meter that measures the detuning frequency.
The digital display functions as a clock when the power switch is turned off. The switch can also be used to check the time during reception.
The front end section uses a 5-row varicon system.
The intermediate frequency circuit combines a surface acoustic wave (SAW) filter and an LC filter with excellent selectivity and delay characteristics in order to achieve both high selectivity and low distortion.
The SAW filter is an abbreviation of Surface Acoustic Wave. It consists of two sets of piezoelectric bodies with comb-shaped electrodes facing each other. The oscillation side is piezoelectrically excited, surface vibration is transmitted to the receiving electrode, and it is converted again to electricity. It is a new filter that can determine the frequency and bandwidth by the elasticity of the material and the shape of the electrode. It maintains stable performance over a long period of time.
In addition, the selectivity is switched in two stages, Normal (low distortion rate) and Narrow (high selectivity), so that adjacent interference is considered.
The detector is a transformer type detector that obtains an audio signal by multiplying the input wave by a signal that has passed through a phase shifter (a circuit that displaces phase shift) that changes linearly according to frequency around 90 degrees.
This wide-band linear phase shifter achieves nearly distortion-free detection characteristics.
A PLL demodulator with a built-in circuit for removing the pilot carrier is used to demodulate the left / right composite signal into stereo.
It is equipped with two meters : a 0 center meter (with detuning frequency scale) for accurate tuning and a meter that can be checked by switching between "input signal level", "modulator" and "multipath" with a switch.
The input signal level can be on a dBf direct reading scale, the modulation degree is 200% in full scale with peak support, and the multipath direction can be determined by a clear mark.
It is equipped with a noise filter to reduce noise when receiving weak stereo signals, a mode switch to switch the stereo broadcast transmission to monaural, a muting switch to remove inter-station noise, and a dimmer switch to dim the frequency-indicator.
We have a separately sold natural wood Rosewood cabinet.
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Model Rating
| Type | Digital display FM tuner | |||||||||
| MonAural Characteristics | ||||||||||
| Sensitivity | Practical sensitivity : 11.2 dBf S/N50dB sensitivity : 17.3 dBf |
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| Standing-wave ratio | 1.5 | |||||||||
| S/N (65 dBf input) | 77dB | |||||||||
| Harmonic distortion factor (65 dBf input Selectivity switch Normal) |
100 Hz : 0.03% or less 1 kHz : 0.03% or less 6 kHz : 0.03% or less 10 kHz : 0.04% or less |
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| IM Distortion Factor (14 hz : 15 khz = 1 : 1) | 0.01% or less (antenna input 65 dBf, 100% modulation) | |||||||||
| Frequency characteristic | 20 Hz ~ 15000 Hz + 0 -0.5 dB | |||||||||
| 2-signal selectivity (45 dBf input) |
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| Capture ratio | 1.5dB | |||||||||
| RF intermodulation | 75dB | |||||||||
| Spurious interference ratio | 120dB | |||||||||
| Image ratio | 120dB | |||||||||
| IF/2 spurious response | 100dB | |||||||||
| AM suppression ratio (65 dBf input) | 80dB | |||||||||
| Subcarrier suppression ratio | 80dB | |||||||||
| SCA interference ratio | 80dB | |||||||||
| Output voltage (100% modulation) | 1.5V | |||||||||
| Stereo Characteristics | ||||||||||
| Sensitivity | S/N 40 dB sensitivity : 28.8 dBf S/N 50 dB sensitivity : 37.3 dBf |
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| S/N (65 dBf input) | 75dB | |||||||||
| Harmonic distortion factor (65 dBf input) | 100 Hz : 0.03% or less 1 kHz : 0.03% or less 6 kHz : 0.05% or less 10 kHz : 0.1% or less |
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| IM Distortion Factor (9 kHz : 10 kHz = 1 : 1) | 0.03% or less (antenna input 65 dBf, stereo 100% modulation) | |||||||||
| Frequency characteristic | 20 Hz ~ 15000 Hz + 0 -0.5 dB | |||||||||
| Stereo separation factor | 100Hz:50dB 1kHz:50dB 10kHz:45dB |
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| Stereo switching input voltage | 10.2dBf | |||||||||
| <General> | ||||||||||
| Receiving frequency | 76.0 mhz ~ 90.0 mhz, continuously variable | |||||||||
| Frequency display | 100 kHz sense, rounded to 10 kHz | |||||||||
| Tuning system | Precision 5-row variator | |||||||||
| Frequency stability | Within ± 30 khz | |||||||||
| Output impedance | Fixed output terminal : 200 Ω Variable Output Terminal : 2.5k Ω |
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| Antenna input impedance | Balance : 300 Ω Unbalanced : 75 Ω |
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| Meter | 2 pieces Signal Intensity Meter / Multipath / Modulation Switching Type Center tuning |
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| Digital clock | Crystal oscillation type Accuracy : within ± 15 seconds per month at 20 ° C |
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| Semiconductor used | FET : 5 pcs Transistor : 24 IC : 13 Diode : 25 pcs |
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| Pwer | 100 V, 50/60Hz | |||||||||
| Power consumption | 25W | |||||||||
| External dimensions | Width 445x Height 128 (Including Legs) x Depth 370 mm | |||||||||
| Weight | 10.0kg | |||||||||
| Sold Separately | Wood Cabinet A-9 (¥ 15,000) | |||||||||