YAMAHA T-3

Commentary

FM stereo tuners incorporating Yamaha audio technology.

The front-end section is equipped with a frequency-linear 5-row varicon, and the antenna input section and stage section are double-tuned. The RF amplifier is equipped with a dual-gate MOS FET to improve various interference rejection characteristics.

The IF section is equipped with a Local position that emphasizes audio characteristics and a DX position that is most suitable for reception environments with a lot of interference. By adopting an Auto-DX circuit that automatically switches to the DX position, high-quality reception is possible.

The configuration of the IF stage at the Local position employs two newly developed ceramic filter elements, the IF amplifier is equipped with a buffer amplifier to suppress impedance fluctuation, and a 7-stage differential amplifier with a current limiter with excellent limiter effect is equipped with a phase distortion correction circuit.
In the DX position, two newly developed ceramic filter elements are added to the Local position to improve the selectivity and cut the interference sharply.

In the MPX section, we have developed and installed a DC-NFB switching PLL type stereo decoder using a newly developed high-speed, low-distortion DC amplifier.
This circuit is based on a high-speed DC amplifier and consists of an average demodulation switching circuit using Yamaha's proprietary transistors and NFB, similar to audio amplifiers. This realizes a circuit with excellent phase and transient characteristics from the ultra-low band to the high-band band and low intermodulation distortion.
The pilot signal cancellation circuit eliminates the 19 kHz pilot signal that is unnecessary as an audio signal before entering the decoder, so the cutoff frequency of the low-pass filter can be higher than 19 kHz.

The PLL circuit that generates 38 kHz sub-carriers from 19 kHz pilot signals uses the Anti-interference PLL System, in which a tunable interference filter is added to the input to reduce sub-carrier disturbance caused by stereo audio signals.

Equipped with an automatic tuning hold system (ATS) that automatically holds the frequency of the local oscillator when it is tuned to the desired station.

Equipped with a muting circuit.
A timing circuit is also provided for muting noise generated when the power is turned on/off.

The signal meter uses interference detection type meters.
By turning off the Muting/ATS switch, the presence of unwanted radio waves such as multipath and fading is displayed as a drop in support value or a wamble of the needle.

A 333 Hz test signal generation circuit is built in.
The output level is set to 50% modulation level of the FM output level.

Model Rating

Type	FM stereo tuner
FM practical sensitivity (IHF, 300 Ω)	Mono : 1.8 μ V/10.3 dBf
Image interference ratio	120dB
IF interference ratio	100dB
Capture ratio	1.0dB
Effective selectivity (IHF)	Local:45dB DX:82dB
Signal-to-noise ratio	mono:86dB stereo:84dB
Total harmonic distortion factor	mono: 0.05%(Local) 0.15%(DX) stereo: 0.05%(Local) 0.5%(DX)
Stereo separation	Local:55dB DX:30dB
Frequency characteristic	30 Hz to 15 kHz ± 0.5 dB
Subcarrier suppression ratio	65dB
Accessory circuit	Auto DX circuit ATS Blend switch Rec calibrator Muting Signal Quality Meter
Power supply voltage	100 VAC, 50Hz/60Hz
Rated power consumption	9W
External dimensions	Width 435x Height 94x Depth 332 mm
Weight	5.5kg