YAMAHA CT-X11
¥ 59,000 (around 1978)
Commentary
An FM/AM tuner equipped with a DX position in the IF stage to cope with the radio wave environment.
For the front end, a J-FET with excellent high-frequency characteristics and a frequency linear type 3-row variable capacitor are adopted.
In addition, the operation level of the mixer stage, which converts received radio waves to an intermediate frequency of 10.7 MHz, is carefully examined to improve the characteristics of the entire front end.
The IF stage is equipped with a DX position that employs four low-spurious ceramic filters and a 7-stage differential amplification IF amplifier with a current limiter by an IC with good limiter characteristics to improve especially the interference rejection characteristics.
In the Normal position, a 4-element low-spurious ceramic filter and a phase correction circuit, which have been thoroughly examined by the differential gain direct-viewing analysis method, are employed to achieve a low distortion rate and high separation.
The MPX section uses Yamaha's original average demodulation circuit, subcarrier generation circuit using PLL / IC, and low-distortion wide-band NFB / PLL / MPX circuit by applying NFB like audio amplifier.
In addition, it employs a pilot cancellation circuit that cancels the 19 kHz pilot signal required to demodulate the composite signal into a stereo signal at the entrance of the decoder, enabling wide-band playback.
Equipped with a 333 Hz test signal generation circuit that enables easy level adjustment during recording.
Equipped with a signal quality meter that detects interference.
In addition to the signal meter function of indicating the level of incoming radio waves, this meter can detect the quality of radio waves and indicate that the indicator light is unstable when the radio wave condition deteriorates.
Model Rating
Type | FM/AM stereo tuner |
FM Tuner Section | |
FM practical sensitivity (IHF, 300 Ω) | Mono : 1.6 μ V/9.3 dBf |
Image interference ratio | 55dB |
IF interference ratio | 80dB |
Capture ratio | 1.0dB |
Effective selectivity (IHF) | Normal:55dB DX:85dB |
Signal-to-noise ratio | mono:80dB stereo:75dB |
Total harmonic distortion factor (1 kHz, Normal) |
mono:0.07% stereo:0.08% |
Stereo separation | 45 dB (1 kHz, Normal) |
Frequency characteristic | 30 Hz ~ 15 kHz + 0.5 -1.0 dB |
Subcarrier suppression ratio | 45dB |
<AM Tuner Section> | |
Practical sensitivity | 18 μ V |
Selectivity (IHF) | 25dB |
<General> | |
Accessory circuit | IF DX Position FM Blend Muting Output level volume Rec calibrator Signal Strength/Quality Meter |
Power supply voltage | 100 VAC, 50Hz/60Hz |
Rated power consumption | 8W |
External dimensions | Width 435x Height 160x Depth 334 mm |
Weight | 6.3kg |