Marantz SM-9
¥ 225,000 (around 1982)
Commentary
This is a stereo power amplifier developed based on Marantz's tradition of making full use of the best power device with the best operation and best circuit.
For all stages push-pull full DC configuration circuit, super high fTBy using a (90 MHz) power transistor, bare characteristics are greatly improved.
Marantz's unique Low-TIM design, which eliminates transient intermodulation distortion by reducing NFB, provides high-quality Class AB output from low level to maximum output.
The power supply section is equipped with a large-capacity transformer for the power amplifier stage, with the secondary side fully wound on the left and right sides. In addition, the voltage amplifier stage is equipped with a dedicated transformer to reduce interference between channels and stages.
In addition, the use of a 15,000 μ Fx4 filter condenser with excellent high-frequency characteristics and other highly reliable configurations ensures stable and ample power supply capability.
High-purity oxygen-free copper wires are used for all lead wires including transformer lead wires.
In addition to the sub-speaker terminal which can be switched to 1/2, a direct speaker terminal which does not use contact is mounted.
The protection circuit uses an energy sensor type that detects excessive output and keeps the drive transistor signal within a safe range.
It is designed with an emphasis on musical quality by releasing the output to make constant motion without interrupting the performance.
The front panel is equipped with a high precision peak meter and a traditional sub-panel, and is designed to be housed in a mahogany cabinet.
Model Rating
| Type | Stereo power amplifier |
| Rated Output (20 Hz ~ 20 kHz, Simultaneous Operation for Both Channels) | 150W + 150W (8 Ω) |
| Total harmonic distortion factor (20 Hz to 20 kHz, at rated output) | 0.01% or less |
| Cross modulation distortion factor | 0.01% or less |
| Frequency characteristic | DC ~ 100 kHz + 0 -1dB |
| Input Sensitivity / Impedance | 1.5V/30k Ω |
| Damping factor | 100 or More (1 kHz, 8 Ω) |
| Signal-to-noise ratio (IHF-A) | 120dB |
| Rated power consumption (Electrical Appliance and Material Control Law) | 400W |
| External dimensions | Width 474x Height 172x Depth 345 mm |
| Weight | 23.5kg |