Marantz 1070

 The Marantz Model 1070 stereo console amplifier was designed by American engineers, but is manufactured under their control in Japan. With a total power output approaching 100 watts RMS, it is compact in comparison with many competitive amplifiers, yet has a wide range of facilities.

 The amplifier is fully screened, with a metal housing finished in imitation wood veneer, and the brushed aluminium front panel is protected by a removable clear plastic cover. The main controls are mounted on a recessed black anodized panel with a clear perspex protective cover over the lettering and control calibrations. This panel is not back illuminated and therefore it is essential that the panel is placed in a good light. The controls on the front panel are a large selector knob for phono, tuner, auxiliary, tape 1 and tape 2. Next comes the tape monitor switch which can select either of two tape machines. In the centre are three slider-type tone controls for bass, mid-range and treble. To the right of these controls is the mode selector switch for left, right, Stereo, stereo reverse, and mono L R, and finally the rotary volume control. Below the main controls are the following: sockets for stereo microphone and headphones, push-buttons for low filter, high filter, loudness, main speakers, remote or ambience speakers, and power on-off. In the centre is the balance control.

 There are four fuses to protect the amplifier and loudspeakers but to gain access to these it is neces.snry to remove the outer top cover. The well-designed rigid chassis carries a heavy Marantz Model 1070 stereo amplifier power transformer, fully screened. Separate printed circuit boards are used for the stabilized power supply, the input pre-amplifiers and tone control circuits. The fully complementary output stages are mounted on heavy heat sinks together with the penultimate driver stages. Whilst conventional soldering is used on switches, plugs etc, inter-panel wiring makes use of wrapped joints, a technique claimed to have a lower contact resistance than soldered joints.

 On the rear panel are eight spring-loaded terminals for the main and remote pairs of loudspeakers, and below these are a 200W unswitched AC mains flat-contact American socket and a similar switched 100W one. Normally the pre-amplifier is directly connected to the power amplifier but, with the gradual use of graphic equalizers, for example, it is desirable to separate the pre-amplifier from the power amplifier. In the case of the Marantz 1070 this is achieved by having left and right 'pre-out' and `main-in' phono sockets on the rear panel. These automatically bridge together but, when a phono plug is inserted, the internal connection is interrupted and any external unit can be connected between the two parts of the amplifier. There are input and output phono sockets for two separate tape recorders, duplicated with DIN sockets. Finally there are three pairs of phono sockets for phono, tuner and auxiliary. A 168cm (66-inch) three-core mains cable is permanently fixed to the amplifier.

Specifications

Gain-Phono (low level) to pre-amp:  55 dB

Phono to recording output:  40 dB

High level to pre-amp output:  15 dB

Input Impedance

Low level input Phono, Microphone:  47 kΩ

High level input:  >50 kΩ

Input sensitivity

Phono (low):  1,8 mV to equal 1 volt output at pre-amp out

Frequency Response:  20 - 20,000 Hz;  ±1 dB at rated power output

Intermodulation Distortion:  Less than 0,3% at rated power output (SMPTE)

Damping Factor (20-20,000 Hz):  Greater than 20 into 8Ω load

Total Noise

From magnetic phono input to power amp output:  Less than 1,5 μV equivalent input at rated output into 8Ω

Volume Tracking:  Within 3 dB

Rated Power Output (continuous average per channel, all channels driven)

Power output:  38 watts into 4Ω

Power band:  20 - 20,000 Hz

Total Harmonic Distortion:  0,3%

Power requirement:  120, 220, 240 V AC 50/60 Hz

At rated output both channels operating:  190 Watts

Idling Power (volume channels at zero):  48 Watts

Dimensions (W x H x D):  14-11/64 x 4-23/32 x 11-1/32 inches

Weight net:  18 lbs