Audio Database

ST-8
Commentary

FM/AM tuner that employs quartz lock gyro touch tuning.

It uses quartz lock gyro touch tuning which is a further development of Marantz original gyro touch tuning.
The quartz lock system uses a crystal reference signal to accurately lock the frequency at every 100 kHz to improve the stability of tuning. The ST-8 also detects signals not only from the front end but also from the IF final stage to improve the accuracy.

It is equipped with a multi-work oscilloscope that can monitor at a glance not only the precise tuning point but also the state of multipath and separation. The meter has a blue glow that accurately shows the radio wave condition and creates a unique atmosphere.
You can also monitor the separation characteristics of the deck or amplifier by connecting the Scope Input jacks to other components.

A low-noise dual-gate MOS FET is used in the front end section to obtain excellent high-frequency amplification characteristics.

The IF stage employs a linear phase IF circuit in which the main and sub circuits are independent. The main IF circuit for sound quality and the sub IF circuit for multipath muting are independent.
The main IF circuit is configured with a 4-pole linear phase LC filter with excellent group delay characteristics as well as wide-narrow switching according to the radio wave environment. Moreover, it is configured with an emphasis on sound quality by adding a newly developed surface acoustic wave filter (SAW).
In narrow band mode, spurious characteristics and selectivity characteristics are improved by cutting unnecessary bands.

The FM-IF stage has a built-in LC-type anti-stereo filter to cut off the excess Birdie in the circuit, realizing a high SN ratio and low distortion factor at FM stereo reception.

The MPX stage is equipped with a PLL pilot canceler circuit to obtain stable stereo separation.

There was a wood cabinet sold separately.

Model Rating
Type FM/AM Tuner
FM Tuner Section
Receiving frequency 76 to 90 MHz
IHF sensitivity 9.3dBf/1.6 μ V
50 dB quadrature sensitivity Monaural : 2.8 μ V (IHF), 14.1 dBf
Stereo : 28 μ V (IHF), 34.2 dBf
Chinese arrowhead etting slope 58dB(20dBf)
64dB(25dBf)
76dB(40dBf)
Signal-to-noise ratio Mono : 84 dB
Stereo : 80 dB
Harmonic distortion factor Monaural, Wide / Narrow : 0.04% / 0.07%
Stereo / Wide / Narrow : 0.06% / 0.08%
Frequency characteristic + 0.2 dB, -1dB (30 Hz to 15 kHz)
Capture ratio 0.8 dB (wide)
1.2 dB (narrow)
Effective selectivity 50 dB (wide)
90 dB (narrow)
Image rejection ratio 120dB
Intermediate frequency interference ratio 120dB
AM suppression ratio 70dB
Stereo separation 48dB(100Hz)
55dB(1kHz)
45dB(10kHz)
<AM Tuner Section>
Receiving frequency range 535 to 1605 kHz
Sensitivity 10 μ V
Signal-to-noise ratio 55dB
Selectivity 60dB
Image rejection ratio 80dB
<General>
Rated power consumption 30W
Pwer 100 VAC, 50/60Hz
External dimensions Width 416x Height 146x Depth 302 mm
Weight 9kg
Sold Separately Cabinet WC-77 (Walnut Finish, ¥ 8,000)
WC-77N (Mahogany Finish, ¥ 12500)