Audio Database

SM-11
Commentary

This is a stereo power amplifier that Marantz completed by taking the right approach that he had accumulated through the development of various high power amplifiers.

In order to obtain high power with high quality, power transistors with especially excellent linearity are adopted. A total of 16 power transistors are used in a 4-parallel 3-stage Darlington circuit configuration.
In addition, by adopting a cascode circuit for all voltage amplification stages, simplification has been achieved, and bare characteristics have been improved to achieve low noise and low distortion without applying a large amount of NFB.

The power supply section is equipped with a high-regulation large power transformer and a specially developed custom electrolytic capacitor for audio.
Electrolytic capacitors, in particular, use computer-grade high-grade screw terminals to achieve high reliability.

Equipped with a large peak power meter.
By adopting logarithmic compression type indication, it is possible to monitor from small output to maximum output without switching the range.
The recovery time of the meter can be switched between Normal and Peak Hold by the switch on the front panel.

Equipped with a remote AC cord that enables you to turn the power of the power amplifier ON/OFF on the preamplifier side without passing a large current directly into the preamplifier.
This eliminates large current, which is a source of noise, from the interior of the preamplifier, which deals with weak signals, and reduces the effect on sound quality.

Model Rating
Type Stereo power amplifier
Rated output 300W + 300W (4 Ω)
265W + 265W (8 Ω)
Total harmonic distortion factor Not more than 0.008%
Frequency characteristic 10 ~ 100 kHz + 0 -1dB
Input Sensitivity / Input Impedance 1.5V/22k Ω
Damping factor 100 or More (8 Ω)
Signal-to-noise ratio (IHF-A) 120dB
Power consumption (Electrical Appliance and Material Control Law) 400W
External dimensions Width 454x Height 200x Depth 476 mm
Weight 30kg