KRELL KSA-50mkII
¥ 820,000 (around 1985)
Commentary
Stereo power amplifier with pure A-class operation.
The circuit configuration employs a pure complimentary service circuit of perfect symmetry with carefully selected elements, and NFB is suppressed to 15 dB with an emphasis on dynamic characteristics.
The Power Block eliminates heat generation by combining a heat sink and an extremely quiet cooling fan, and thermal distortion is suppressed by strictly controlling the temperature of the Power Block to 75 to 80 degrees Celsius at all times.
Both sides of the power supply section are completely independent, and each channel is equipped with a 80,000 μ F condenser and a 800W class large toroidal transformer. This structure is resistant to load fluctuations during music playback and enables stable and comfortable playback even when the speaker impedance drops to nearly 1 Ω.
The internal construction is a fully twin-monaural configuration with sufficient space between each block to prevent mutual interference due to signal jumps and to improve thermal stability.
Equipped with a switch for BTL connection, it can also be used as a high-power monaural power amplifier with BTL connection.
Model Rating
| Type | Stereo power amplifier |
| Rated output | 50W + 50W (8 Ω, both channel operation, 20 Hz to 20 kHz) 200W (8 ω, BTL connected, 20 Hz to 20 kHz) |
| 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 (1W ~ Rated Output) |
0.5 Hz to 100 kHz -3dB 20 Hz to 20 kHz -0.5 dB |
| 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) 550W (maximum with BTL connected) |
| External dimensions | Width 483x Height 226x Depth 480 mm |
| Weight | Approx. 24 kg |