Marantz Model 115
¥ 64,900 (around 1972)
Commentary
FM/AM tuner developed using Marantz's tuner technology known as 10B, etc.
Marantz U.S.A. designed and checked it, and shipped it.
Marantz's unique gyro-touch tuning is used for tuning.
Since this system directly turns a large flywheel, it can perform smooth and accurate tuning.
Muting is controlled by three types of inputs.
The first relates to the signal strength, the second relates to the state of noise in the detector, and the third relates to the DC component of the detected output.
Muting works by the combination of these three, and noise and spurious between stations are completely shut out.
In addition, the exciting pop noise generated at the time of entrance and 離局 is suppressed.
You can also change the muting level with the threshold knob.
The front end uses FET for the mixer stage, and the IF stage is based on the same design concept as the old 20B. It consists of 6 ceramic filters and 4 stage limiters.
The limiter uses a hot carrier diode and the dynamic aperture is very narrow, so that the unnecessary AM part is removed and the capture ratio is also improved.
In addition, the coil of the MPX stage is sealed with epoxy to improve stability and reliability.
Output terminal for 4-channel decoder is provided.
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Model Rating
| Type | FM/AM Tuner |
| FM Tuner Section | |
| Sensitivity | 1.9 μ V75 Ω (IHF) |
| Separation | 42dB(1kHz) |
| Capture ratio | 1.6dB |
| Distortion factor | mono:0.15% stereo:0.3% |
| Spurious interference ratio | 95 dB or more |
| Image ratio | 70 dB or more |
| AM suppression ratio | 60 dB or more |
| IF interference ratio | 90 dB or more |
| Selectivity | 60 dB or more |
| Signal-to-noise ratio | Mono : 70 dB or higher Stereo : 60 dB or more |
| <AM Tuner Section> | |
| Sensitivity | 20 μ V or more |
| <General> | |
| External dimensions | Width 390x Height 146x Depth 300 mm |
| Weight | 7.9kg |