LUXKIT A220
¥ 30,500 (released in August 1972)
¥ 37,800 (around 1974)
Commentary
A control amplifier kit using transistors.
Ultra-low-noise transistors are used in all stages to reduce noise.
The equalizer stage uses a 3-stage direct-coupled circuit that combines PNP-NPN-PNP type transistors. This configuration has higher voltage utilization, better linearity, and a wider dynamic range than a 2-stage direct-coupled circuit.
Moreover, by selecting appropriate circuit constants in consideration of stability and high-frequency distortion factor, stability on the circuit and stability due to external factors are improved.
The NF type of the Lux-type tone control is used. In addition, the curve point switching function is provided in two positions for both high and low band for fine adjustment.
It is equipped with high and low filters, attenuators, and amplifiers for headphones.
* There was a supplement about amplification and input resistance in the catalog at that time.
In the equalizer amplifier of A220, the input sensitivity of the phono terminal can be changed by changing the resistance of the feedback circuit (β circuit). Specifically, if R3 in the circuit diagram is reduced, the amplification becomes larger and the input voltage resistance becomes smaller. Conversely, if R3 is increased, the amplification becomes smaller and the input voltage resistance becomes larger.
The practical range of R3 is from 330 Ω to 1k Ω, beyond which there are adverse effects in terms of signal-to-noise ratio and stability.
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Model Rating
| Type | Control amplifier kit | |||||||||||||||||
| Amplifier Unit | ||||||||||||||||||
| Output Voltage / Impedance | Pre out : 1 V (Rated) / 200 Ω | |||||||||||||||||
| Total harmonic distortion factor | 0.08% or Less (1 V, 55 Hz to 10 kHz) | |||||||||||||||||
| Frequency characteristic | 20 Hz to 20 kHz -0.5 dB or less | |||||||||||||||||
| Input Sensitivity / Impedance | Phono1, 2 : 1.8mV/50k Ω Aux1, 2, 3 : 130mV/100k Ω |
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* Value of R3 and input sensitivity / input voltage resistance (1 khz)
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| Signal-to-noise ratio (input short, uncorrected) | Phono1, 2 : 60 dB or more Aux1, 2, 3 : 77 dB or more |
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| Equalizer | RIAA deviation ± 0.5 dB | |||||||||||||||||
| Tone control | LUX System NF Type with Bending Point Switching Low-range bending point : 250 Hz, 500 Hz High-frequency curve point : 2.5 kHz, 5 kHz |
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| Low filter | 50 Hz, -6dB/oct. | |||||||||||||||||
| High filter | 8 kHz, -6dB/oct. | |||||||||||||||||
| Recording output | Rec out:130mV | |||||||||||||||||
| Attachment | Tape monitor switch Attenuator (-20dB) |
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| Headphone Amplifier Section | ||||||||||||||||||
| Maximum power output | 50 mW (8 Ω) | |||||||||||||||||
| Total harmonic distortion factor | Not more than 1% | |||||||||||||||||
| Frequency characteristic | 20 Hz to 20 kHz) | |||||||||||||||||
| <Others> | ||||||||||||||||||
| Semiconductor used |
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| External dimensions | Width 400x Height 130x Depth 245 mm | |||||||||||||||||
| Weight | 3.8kg | |||||||||||||||||
| Sold Separately | Assembly Manual (¥ 500) | |||||||||||||||||
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