KRELL KSA-50
¥ 660,000 (released in 1980)
Commentary
This is a stereo power amplifier located in a low-price model with small output.
The circuit operation adopts the orthodox pure A class operation.
In addition, the circuit system employs a pure complementary circuit with perfect symmetry using carefully selected elements, and NFB is suppressed to 15 dB with an emphasis on dynamic characteristics.
Construction is fully twin-monaural, with sufficient space between each block to prevent mutual interference due to signal jumps and to improve thermal stability.
The Power Block combines a heat sink and an extremely quiet cooling fan to eliminate heat generation and to control the temperature of the Power Block strictly from 75 to 80 degrees Celsius at all times to prevent thermal distortion.
The power supply configuration of a B-class power amplifier is comparable to that of a 200W-class power amplifier. The left and right channels are completely independent, and a 80,000 μ F capacitor and a 800W-class large toroidal transformer are installed. This makes it resistant to load fluctuations during music playback and enables stable and comfortable playback even if the speaker impedance drops to nearly 1 Ω.
Model Rating
| Type | Stereo power amplifier |
| Rated output | 50W + 50W (8 Ω, 20 Hz to 20 kHz, when both channels are driven simultaneously) 100W + 100W (4 Ω) 200W + 200W (2 Ω) |
| Input Sensitivity / Impedance | 0.84V/22k Ω |
| Total harmonic distortion factor | 0.05% or Less (20 Hz to 20 kHz, 1W to Rated Output) |
| Frequency characteristic | 0.5 Hz ~ 100 kHz -3dB 20 Hz ~ 20 kHz -0.5 dB (1W ~ Rated Output) |
| Signal-to-noise ratio (IHF-A) | 120dB |
| Rated load impedance | 2 Ω or more |
| Damping factor | 100(1kHz) |
| Slew rate | 80 v / μ sec |
| Pwer | 100 VAC, 50Hz/60Hz |
| Power consumption | 310W (maximum idling) |
| External dimensions | Width 483x Height 226x Depth 480 mm |
| Weight | Approx. 24 kg |
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