Marantz SM1000
¥ 950,000 (released in 1979)
Commentary
This is a stereo power amplifier developed by putting in all the technologies of Marantz at that time and eliminating all the cost constraints.
All stages of the power block are completely push-pull configuration in order to take out the large output of 400W single-channel with high quality and stability.
In addition, it uses 18 single-channel power transistors of up to 200 W PC, divided into 6 groups of 3 transistors each and driven by 6 drivers. It is a luxurious circuit that uses only the best parts of hfe reality.
With our unique Low-TIM design, the open-loop gain is kept at an extremely low level of 56 to 57 dB, so that the amount of NF, which adversely affects dynamic characteristics, is reduced to the same level as a vacuum tube amplifier.
On a highly reliable glass-epoxy double-sided through-hole substrate developed for computers, dual transistors and diode array with ideal characteristics are used at each point. These elements are arranged in perfect symmetry to perfectly switch electrical and thermal coefficients and eliminate DC drift from materials and circuits.
The sound quality deteriorates as the number of contact points increases. The SM1000 does not include a speaker protect relay because it allows a direct signal with no contact points to the speaker terminals. In the unlikely event that a DC component occurs in the speaker, a unique SCR crowbar circuit detects it, immediately cuts the fuse on the primary side and discharges the energy inside the power supply capacitor, protecting the speaker faster and more reliably than relay protectors.
Cut core transformer with capacity of 800 VA. Equipped with 23500 μ Fx2 large capacity audio condenser of Marantz custom made to pursue sound quality thoroughly from listening characteristics.
The SM1000 consists of two monaural amplifiers, each of which is completely independent on the left and right.
The power transistor's heat dissipation device uses a FingerHeat Disi Peter developed from NASA technology.
We have further improved the one demonstrated in P. 510. Five types of fins with different lengths are attached to each power transistor and forced air cooling is performed by a cooling fan.
Moreover, by detecting the temperature of the heat sink and automatically changing the rotation of the cooling fan to keep it at a constant temperature, the sound quality is prevented from changing due to uneven temperature.
It uses a logarithmic compression support type power meter that can monitor from small output to large output without range switching. Although it is peak operation, the value indicated by the exponent is the output display for 8 Ω operation as it is.
In addition to the direct terminals that do not pass through any switches, the speaker terminals are the total Route 3 of SUB1 and SUB2 that can be switched by a switch in the front ceiling panel.
Input terminal for selecting DC amplifier or AC amplifier.
In addition to the RCA pin terminal, it is equipped with a cannon terminal that can also be used as a pro user.
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Model Rating
| Type | Stereo power amplifier |
| Rated Output (20 Hz ~ 20 kHz) | 400W + 400W (8 Ω) 650W + 650W (4 Ω) |
| Total harmonic distortion rate (20 Hz to 20 kHz) | 0.01% (8 Ω) 0.03% (4 Ω) |
| Frequency characteristic | (+ 0, -1dB) : DC ~ 100 kHz |
| Input Sensitivity / Input Impedance | 2.83V/27k Ω |
| Damping factor | 300 (8 Ω) |
| Residual noise | 26 μ V (A Network) |
| Signal-to-noise ratio | 126 dB (A Network) |
| Power consumption | Electrical Appliance and Material Control Law : 985W |
| Pwer | 100 V, 50/60Hz |
| External dimensions | Width 483x Height 178x Depth 550 mm |
| Weight | 42kg |