Audio Database

SC-7
Commentary

A control amplifier developed for Low-TIM.

The equalizer stage is responsible for amplifying the weak output from the record and compensating for the recording characteristics. The first stage is a cascode differential circuit with low-noise FET → phase inversion amplifier, the second stage is a complete push-pull amplifier circuit, and the output stage is a DC-configuration equalizer stage with low distortion and good transient characteristics with Darlington SEPP. Furthermore, the first stage FET is a luxurious FET specially made by Marantz that has low-noise characteristics and excellent thermal and electrical pair characteristics. As a result, the S/N ratio is exactly 90 dB (IHF-A) at 7.75 mV input. In addition, the RIAA deviation, which indicates the accuracy of record reproduction, is ± 0.2 dB (20 Hz to 20 kHz) by carefully selecting an equalizer element with good characteristics and high accuracy.

It has a built-in MC head amplifier, a DC configuration using a low-noise FET at the first stage, and an extremely low feedback impedance to improve the S/N ratio.

While listening to FM music, you can record completely different sources on each of the two decks independently, from the Phono input on the A deck and from the AUX terminal on the B deck. This not only expands deck play, but also eliminates the hassle of pin plug connections when dubbing from deck to deck, and improves playability.

For faithful disc playback, the impedance matching between the cartridge and the amplifier must be accurate. The SC-7 comes with a selector that can be easily adjusted to 5 levels of 1k Ω ~ 100k Ω for MM type and 4 levels of 10 Ω ~ 220 Ω for MC type.

It is equipped with a tritone control for room equalization in any sound field. The tone amplifier is composed of DC-differential amplifier using FET → full push-pull amplification → SEPP. It is a BAX type with good control characteristics. In addition to the BASS TREBLE, it is equipped with the MID control for mid-range correction. The TURN-OVER switch switches the turnover frequencies from 2 kHz to 10 kHz for High and from 500 Hz to 100 Hz for Low. It is also equipped with a variety of functions from room acoustic to program correction. For example, tone correction can be added to the source during recording by linking with the TAPE EQ switch.

The tone bypass switch allows the phono signal to be sent directly to the PRE-OUT without passing through the tone circuit with a single switch.

A headphone amplifier of high sensitivity A class 0.5W design, volume control with low noise with 4-connection type volume adoption, gold finish input / output terminal which prevents sound quality degradation, etc. are substantial.

Model Rating
Type Stereo control amplifier
Rated Output / Impedance PRE-OUT : 1.5V/100 Ω
TAPE-OUT : 150mV/250 Ω
Input Sensitivity / Impedance Phono1 ・ 2 (MM) : 2mV/1k Ω, 10k Ω, 27k Ω, 47k Ω, 100k Ω
Phono2 (MC) : 200 μ V/10 Ω, 47 Ω, 100 Ω, 220 Ω
High Level : 150mV/40k Ω
Total harmonic distortion factor Not more than 0.004%
Cross modulation distortion factor Not more than 0.004%
Frequency characteristic ± 0.2 dB (RIAA deviation, 20 Hz to 20 kHz)
+ 0, -0.1 dB (High Level, 20 Hz to 20 kHz)
4 Hz to 120 kHz (High Level, + 0, -1dB)
Input equalization noise 0.24 μ V (Phono IHF-A)
Dynamic range 120dB
Phono Maximum Input 250mV(MM 1kHz)
25mV(MC 1kHz)
Tone control ± 10 dB (Low Frequency 100 Hz)
± 6 dB (Mid Range 800 Hz)
± 10 dB (high frequency 10 kHz)
Filter characteristics 9kHz/18dBoct.(High)
15Hz/18dBoct.(Low)
Power consumption 45W
Pwer 100 V, 50/60Hz
External dimensions Width 416x Height 146x Depth 244 mm
Weight 10kg
Sold Separately Cabinet WC-75 (Walnut Finish) : ¥ 7,000
WC-75N (Mahogany Finish) : ¥ 11500