TRIO KT-7100

Commentary

FM/AM tuner designed with an emphasis on sound quality.

The front-end section employs a dual-gate MOS FET and a frequency-straight-line four link varicon, which realizes high sensitivity and large input characteristics sufficient to receive even strong electric fields.

The IF section uses a phase linear 6-element filter with excellent group delay characteristics and an LC tuning circuit to ensure high selectivity.
In addition, wide-band quadrature detection is adopted for the discrete device, and excellent wide-band distortion characteristics are realized by adjusting the offset voltage to eliminate the tuning deviation while obtaining low distortion characteristics.
In addition, a high-gain amplifier stage using a high-integration IC and a 5-stage limiter reduce sound quality degradation.

In the MPX part, a low distortion factor is achieved by examining the tracking filter action when detecting the pilot signal of the PLL, and stable separation is obtained by adopting the PLL which is resistant to aging due to temperature and humidity.
In addition, a 5-element left / right split low-pass filter with Norton conversion improves carrier leakage without deteriorating frequency characteristics.

A 2-stage direct-coupled discrete circuit is used in the preamplifier section, so that a low distortion rate can be maintained even with 300% overmodulation.

In the FM muting circuit, band narrowing is realized by S-curve and IF band detection.
In addition, by adopting the FET switch control method at the high signal level of the audio output, pop noise is almost eliminated and noise between stations is eliminated sharply.
The ± power supply time difference circuit operates at power ON/OFF to prevent pop noise and shock noise.

The AM tuner uses a high-selectivity ceramic filter that combines two 3-terminal ceramic filter elements and a coil in the IF stage and a new type of IC. The RF stage contains a spurious trap circuit that cuts out the outside of the reception band to eliminate beat interference from short wave bands.

All the circuits except for the power transformer are contained in one block board to suppress the deterioration of sound quality caused by wiring such as the influence of stray capacitance of the cord.

Uses a long scale dial and differential pulley with an effective length of 270 mm and a large flywheel with a diameter of 60 φ for smooth tuning without backlash.

The carrying handle in the picture was sold as an optional item sold separately.

Model Rating

Type	FM/AM Tuner
FM Tuner Section
Receiving frequency	76 MHz to 90 MHz
Antenna impedance	300 Ω equilibrium 75 Ω unbalance
SN ratio 50 dB quieting sensitivity	Mono : 3.6 μ V/16.3 dBf (new IHF) Stereo : 43 μ V/37.9 dBf (new IHF)
Sensitivity	1.8 μ V (IHF) / 10.3 dBf (new IHF)
Distortion factor (100% modulation)	mono stereo : : 0.1%(100Hz) 0.1%(1kHz) 0.1%(6kHz) 0.15%(100Hz) 0.15%(1kHz) 0.15%(6kHz)
Signal-to-noise ratio (100% modulation, 1 mv input)	mono:75dB stereo:70dB
Image ratio	90dB
Selectivity (IHF)	75dB
IF interference ratio	100dB
Harmonics spurious response	100dB
AM suppression ratio	60dB
Capture ratio	1.0dB
Stereo separation	50dB(1kHz) 40 dB (50 Hz to 10 kHz) 35dB(15kHz)
Carrier leakage	65dB
Frequency characteristic	50 Hz ~ 10 kHz + 0.2 -0.3 dB 30 Hz to 15 kHz + 0.2 -1.2 dB
<AM Tuner Section>
Receiving frequency	520 kHz to 1,605 kHz
Sensitivity	14 μ V (IHF) 250 μ V/m (bar antenna)
Distortion factor	0.5%
Signal-to-noise ratio (30% modulation, 1 mv input)	50dB
Image ratio	60dB
Selectivity (IHF)	35dB
<General>
Output Level / Impedance	FM (400 Hz, 100% modulation) : 0 V ~ 1.0V/2.5k Ω AM (400 Hz, 30% modulation) : 0 V ~ 0.3V/2.5k Ω
Power supply voltage	100 VAC, 50Hz/60Hz
Rated power consumption (Electrical Appliance and Material Control Law)	14W
External dimensions	Width 430x Height 149x Depth 377 mm
Weight	7kg
Sold Separately	Carrying Handle D-7 (1 set, ¥ 3,000)