Kenwood KA 8300 (1978)
A high-speed DC integrated amplifier with precision MC phono stage and ultra-wide bandwidth
Overview
The TRIO-KENWOOD KA-8300 is a high-performance integrated amplifier released in 1978. Designed for high-fidelity audio systems, it features a fully DC-coupled signal path from input to speaker terminals, with special attention to low-noise MC (moving coil) phono amplification. It was part of Kenwood’s KA series of integrated amplifiers, a line known for technical precision and robust engineering during the late 1970s.
Specifications
| Rated output (both channels, 8 Ω, 20 Hz to 20 kHz) | 80W + 80W |
| Rated output (both channels, 4 Ω, 1 kHz) | 110W + 110W |
| Rated output (both channels, 8 Ω, 1 kHz) | 85W + 85W |
| Total harmonic distortion (Phono to SP, rated output, 20Hz–20kHz) | 0.02% |
| Total harmonic distortion (Tuner/Aux/Tape to SP, rated output, 20Hz–20kHz) | 0.02% |
| Total harmonic distortion (Tuner/Aux/Tape to SP, rated output, 1 kHz) | 0.004% |
| Cross modulation distortion factor (Tuner/Aux/Tape to SP) | 0.003% |
| Frequency response (Tuner/Aux/Tape to SP, DC on) | DC ~ 400 kHz -3dB |
| Frequency response (Tuner/Aux/Tape to SP, DC off) | 18 Hz to 400 kHz -3dB |
| Output Bandwidth (IHF, 0.03% distortion) | 5 Hz to 65 kHz |
| Damping factor | 100 (DC to 20 kHz, 8 Ω) |
| Input Sensitivity/Impedance Phono MM | 2.5mV/50k Ω |
| Input Sensitivity/Impedance Phono MC | 0.1mV/100 Ω |
| Input Sensitivity/Impedance Tuner, Aux, Tape | 200mV/50k Ω |
| Signal-to-noise ratio (IHF-A) Phono MM | 89 dB |
| Signal-to-noise ratio (IHF-A) Phono MC | 68 dB |
| Signal-to-noise ratio (IHF-A) Tuner, Aux, Tape | 110 dB |
| Tone control Bass | ± 7.5 dB (100 Hz, 50 Hz) |
| Tone control Treble | ± 7.5 dB (10 kHz, 20 kHz) |
| Loudness control | +3 dB, +6 dB, +9 dB |
| Transient response Rise time | 0.9 μs |
| Transient response Slew rate | ± 120 V/μs |
| Phono maximum allowable input MM | 220 mV (0.01% distortion) |
| Phono maximum allowable input MC | 8 mV (0.01% distortion) |
| Phono RIAA deviation | 20 Hz to 20 kHz ± 0.2 mV |
| Output Level/Impedance Tape rec | 200mV/120 Ω |
| Power outlet (switch interlock) | 2 |
| Power outlet (unswitched) | 1 |
| Power supply voltage | 100 VAC, 50Hz/60Hz |
| Rated power consumption | 200W |
| Dimensions | 440 x 153 (146) x 403 mm (W x H x D) |
| Weight | 13.5kg |
Design
The KA-8300 is a high-speed DC integrated amplifier with a fully DC-coupled signal path from Tuner/Aux inputs to speaker outputs, eliminating coupling capacitors for improved transient response. The MC phono stage uses an all-stage complementary push-pull DC configuration with ultra-low noise transistors in the first stage, while a newly developed FET is used in the equalizer amplifier’s first stage. The circuit features a cascode-connected FET differential input, direct-coupled differential stages, and a Darlington-connected complementary push-pull output. The power supply uses a large transformer with left/right separated secondary windings and four 10,000μF capacitors, with channels fully separated. The tone control uses a unique NF-CR type with an operational amplifier, and a 3-stage switching loudness control is included.
Market
The KA-8300 was listed for $190 in very good used condition in recent market observations.
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