LUXMAN L-308
¥ 108,000 (released in June 1973)
¥ 120,000 (around 1974)
Commentary
Integrated amplifier with almost the same configuration as the L-309.
The difference from the L-309 is only the output and microphone circuit, and the appearance is almost the same.
The main amplifier uses a 2-power supply system and all stages are directly connected without the capacitor. The complimentary service stage uses a pure power configuration combining PNP type power transistor (2SA680) and NPN type power transistor (2SC1080).
The driver stage is composed of two differential amplification stages, and a circuit is devised to reduce crossover distortion.
The preamplifier section uses a 3-stage direct-coupled equalizer circuit with ultra-low-noise silicon transistors of NPN type (2SC1222) for the first stage, PNP type (2SA640) for the second stage, and NPN type (2SC1222) for the third stage. This circuit has high power utilization and excellent linearity.
The transient characteristics are also improved by applying sufficient DC feedback to this circuit.
A linear equalizer circuit is installed in the intermediate amplifier section after the equalizer circuit.
This circuit is a kind of tone control circuit that can provide two kinds of linear characteristics over the whole band around 1 kHz without affecting the recording output. It can compensate for deviations from the standard RIAA curve over a wide band or unbalanced sources that cannot be easily compensated by conventional tone control.
The tone control circuit uses the LUX system NF type, which has a simple change characteristic, electrical midpoint, and no waviness in the frequency characteristic. The L-308 can switch the bending point frequency by 3 points from low to high, making it possible to fine-tune the sound quality.
There is also a tone defeat switch which can skip this circuit when tone control is not required.
For the filter circuit of the power supply, two 10,000 μ F high ripple type large capacity aluminum electrolytic capacitors are used for + power supply and - power supply. By combining them with a transformer with good regulation, a stable power supply is supplied.
In addition, the power supply for the preamplifier section is constant voltage to prevent cross modulation distortion due to power supply fluctuation.
Equipped with a low-cut filter and a high-cut filter that can select two levels of frequency.
Equipped with a continuously variable attenuator, it can be attenuated from 0 dB to -18dB (approximately 1/8).
Since the attenuator is located immediately after the main section input, it can be used as a level set volume when the main section is used by itself.
Equipped with the Phono input impedance switching function, three levels of impedance can be selected.
It has a level control for the tuner terminal.
Equipped with two speaker outputs.
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Model Rating
| Type | Integrated amplifier | ||||||
| Main Amplifier Section | |||||||
| Continuous effective output | 55W + 55W (8 Ω, both channel operation) 65W/65W (8 Ω, single-channel operation) |
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| Total harmonic distortion factor | 0.03% or Less (8 Ω, 55W) | ||||||
| Cross modulation distortion factor | 0.04% or Less (8 Ω, 55W, 70 hz : 7 khz = 4 : 1) | ||||||
| Power bandwidth | 5 Hz to 50 kHz -3dB (0.03%) | ||||||
| Input Sensitivity / Impedance | 600mV/50k Ω | ||||||
| Residual noise | 0.5 mV or less | ||||||
| Damping factor | 40 (8 Ω, 20 Hz to 20 kHz) | ||||||
| Attachment | Variable attenuator Speaker selector switch Headphone jack AC outlet (Route 3) |
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| Preamplifier Section | |||||||
| Standard output voltage | Pre out:600mV Rec out:100mV |
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| Maximum output voltage | Pre out:5V | ||||||
| Output impedance | Pre out : Approx. 100 Ω Rec out : Approximately 100 Ω |
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| Frequency characteristic | 10 Hz to 50 kHz -1dB (Aux1) | ||||||
| Total harmonic distortion factor | 0.03% or Less (Aux1, 1 khz, 1 v) | ||||||
| Input Sensitivity / Impedance | Phono1 : 2.2mV/50k Ω, 65k Ω, 90k Ω Phono2 : 2.2mV/65k Ω Tuner : 100 mV (with level set) / 50k Ω Aux1, 2 : 100mV/150k Ω |
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| Signal-to-noise ratio | Phono1, 2 : 63 dB or more Tuner, Aux1, 2 : 80 dB or more |
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| Maximum allowable input | Phono : 300 mV or more (1 kHz, RMS) | ||||||
| Tone control | LUX System NF Type with Bending Point Frequency Switching Low-pass curve point : 150 Hz, 300 Hz, 600 Hz High-frequency bending point : 1.5 kHz, 3 kHz, 6 kHz |
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| Filter | Low-cut : 20 Hz, 70 Hz (-6dB/oct.) High Cut : 7 kHz, 12 kHz (-6dB/oct.) |
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| Low boost | 70Hz | ||||||
| Linear equalizer (1 kHz standard) |
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| Attachment | Monitor switch Dubbing switch Input impedance switching DIN connector |
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| <General> | |||||||
| Semiconductor used |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||||||
| Power consumption | 200W (8 Ω simultaneous load at maximum output) | ||||||
| External dimensions | Width 485x Height 165x Depth 300 mm | ||||||
| Weight | 12.5kg | ||||||