Marantz Model 1180
¥ 135,000 (around 1977)
Commentary
A pre-main amplifier that pursues low TIM (transient intermodulation distortion) and transient intermodulation distortion.
The power section is a pure complimentary service OCL parallel push-pull 3-stage Darlington circuit with a Marantz traditional DC-configuration, and uses low-noise elements specially made by Marantz.
In addition, a differential amplification cascode bootstrap circuit using a low-noise specification FET is adopted in the first stage of this power amplifier to minimize temperature drift and time drift which are problems in DC amplifiers.
As a result, we have obtained excellent phase characteristics and transmission capability over a wide band range from ultra-low to ultra-high frequencies. In addition, we have succeeded in putting the concept of Low TIM into practice by eliminating phase distortion in ultra-low frequencies and raising bare characteristics.
Equipped with ESP circuit adopted by P510M.
This ESP circuit instantaneously detects excessive output current and voltage or DC generation at the output terminal, and limits the signal to the driver transistor to a safe value to protect against overdrive and short circuit.
Moreover, it detects frequency and time with instantaneous differential, and provides continuous protection without interrupting the program.
In addition, it is equipped with a relay with a delay circuit (4 seconds) to prevent shock noise caused by power ON. In case of transistor accident, the speaker automatically disconnects.
In actual program playback, the peak of the transient in a source such as direct cutting with a wide dynamic range may exceed the average level by + 10 dB to + 20 dB (10 to 100 times).
It is equipped with a peak indicator that responds instantaneously to such peaks, making level adjustment easy and preventing clipping.
The equalizer amplifier is a 5 tr configuration consisting of a differential input amplifier, a buffer amplifier and a low-current load A class amplifier with a specially designed low-noise element. It is a first stage differential 3-stage direct-coupled differential circuit.
Equipped with a loudness contour, it is possible to fine-tune the low and high frequencies at low volume according to the characteristics of human ears, and to adjust the correction amount by the Fletcher Munson curve in 10 stages according to the volume.
Equipped with Marantz's original tritone control mechanism that can control the MID range.
The Tape Copy mechanism, which can copy from one tape deck to another and can also be monitored, is an independent circuit and can differentiate other sources individually.
It uses a Bessel filter with excellent roll-off characteristics.
A sharp roll-off curve of 18dB/oct. at 9 kHz and 15 Hz has been achieved and phase distortion has been successfully reduced.
Equipped with a tone defeat that jumps the tone circuit and sets the frequency response to flat.
Equipped with a DC/AC amplifier selection switch.
Wooden cabinet is sold separately.
Model Rating
| Type | Stereo pre-main amplifier |
| Rated output (20 Hz to 20 kHz, both channel drive) |
90W + 90W (8 Ω) 115W + 115W (4 Ω) |
| Frequency Response (20 Hz to 20 kHz) | + 0, -0.2 dB |
| Total harmonic distortion factor | 0.03% |
| Cross modulation distortion factor | 0.03% |
| Damping factor | 60 |
| Input Sensitivity / Impedance | Main amplifier input : 1.5V/30k Ω Phono MM : 1.8mV/47k Ω Microphone : 1.8mV/47k Ω High level : 180mV/25k Ω |
| Rated Output / Impedance | Pre Out : 1.5V/200 Ω |
| RIAA deviation (20 Hz to 20 kHz) | + / - 0.2 dB |
| Tone control characteristics | Bass (100 Hz) : + / - 10 dB Mid (700 Hz) : ± 6 dB Treble (10 kHz) : ± 10 dB |
| Filter | Low : 15 Hz, 18dB/oct. High : 9 kHz, 18dB/oct. |
| Power consumption | 240W (Electrical Appliance and Material Control Law) |
| Pwer | 100 V, 50Hz/60Hz |
| External dimensions | Width 416x Height 146x Depth 316 mm |
| Weight | 15kg |
| Sold Separately | Standard Walnut Cabinet WC-110 (¥ 7,000) Standard Mahogany Cabinet WC-110N (¥ 12,000) |