Marantz Model 250
¥ 245,000 (around 1972?)
Commentary
A stereo power amplifier with improved quality at low output.
Resistors, switches and transistors are carefully selected and used.
The circuit configuration employs a differential-amplified, pure complimentary service, and all-stage direct connection OCL circuit.
Both the differential amplifier stage and the push-pull output stage employ a selected perfect pair of transistors, and the basic circuit itself is bare and DC-balanced.
In addition, a DC leakage detection circuit is mounted.
Conventional high-power machines operate in a state close to Class B at the time of small-level reproduction, causing notching distortion peculiar to transistors.
In the Model250, sufficient idling current is supplied for class AB operation to realize excellent bare characteristics.
The printed circuit boards of each block are made independent to avoid interference between the first and last stages.
Model Rating
| Type | Stereo power amplifier |
| Output (at rated output, both channels, 20 Hz to 20 kHz) |
4 Ω : 300W (150W + 150W), Typically 340W 8 Ω : 250W (125W + 125W), Typically 280W 16 Ω : 128W (64W + 64W), Typically 150W |
| Total harmonic distortion factor | 0.1% or Less (20 Hz to 20000 Hz, Rated Output) Typically 0.05% |
| Cross modulation distortion factor | 0.1% or less (at rated output, any two frequencies from 20 Hz to 20 kHz) Typically 0.05% |
| Frequency characteristic | 2 Hz ~ 100 kHz + 0 -1.5 dB 20 Hz to 20 kHz ± 0.1 dB |
| Power Band With (IHF) | 5 Hz to 45000 Hz |
| Input Sensitivity / Impedance | 1.5V/100k Ω |
| Damping factor | 100 or More (8 Ω) |
| <General> | |
| Total Noise | Better than 106 dB below rated power into 8 Ω |
| Pwer | 100 VAC, 50Hz/60Hz 220Volts optional on special order |
| Power consumption | 500W |
| External dimensions | Width 362x Height 156x Depth 241 mm |
| Weight | 12.7kg |