Pioneer C-Z1
¥ 400,000 (around 1980)
Commentary
A non-feedback stereo preamplifier equipped with a super linear circuit that solves the non-linearity of transistors without using any NFB, aiming at an amplifier with 0 transmission error.
In order to obtain excellent characteristics without using NFB, a super linear circuit is mounted.
In this circuit, by the action of the current mirror, the non-linearity of the transistor is canceled by the non-linearity transistor of the reverse mode.
By using a non-feedback amplifier that does not apply NFB, we have obtained the following advantages : "there is no mechanism for generating TIM distortion," "there is no distortion because phase correction is not required, and frequency characteristics are flat over the entire band," and "stability in the high frequency range is good."
In addition, the Super Linear Circuit uses more than 50 elements as modules to improve the reliability, ensure the thermal stability of each element, and provide a shield effect against external noise to improve sound quality.
The C-Z1 uses two Super Linear Circuits per channel for the equalizer stage and one for the flat amplifier. A total of six Super Linear Circuits for two channels are used to realize a non-feedback configuration.
Since a super linear circuit is basically considered as a current amplifier, its gain is determined by the value of the load resistance. Taking advantage of this feature, the C-Z1 uses a current equalizer with RIAA characteristics in the load, which provides excellent maximum allowable input.
Compared with NFB amplifiers, stability of DC voltage at the output point is more important in non-feedback amplifiers.
The C-Z1 uses a double-lock ドサーボ regulator that locks the supply voltage of the super linear circuit, which has been stabilized once, into a double stable state in order to suppress the fluctuation of the midpoint voltage.
In addition, all coupling capacitors, which cause coloring of sound, are removed, and all stages from input to output are directly connected to improve reliability.
In order to prevent adverse effects caused by magnetic materials, we have adopted a non-magnetic structure in which aluminum is used for the chassis, frame, etc.
A glass-case electrolytic capacitor is used to improve sound quality by eliminating distortion current caused by signal current and ripple current.
The printed circuit board uses glass epoxy, which has high strength and excellent high-frequency characteristics.
In addition, the copper foil has a thickness of 140 μ to reduce DC resistance and inductance.
Highly reliable oxygen-free copper materials are used for signal wiring.
A large capacity double insulated power cord is used for the power cord.
Star quad structure connection pin plug cord (oxygen-free copper wire) is equipped as standard.
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Model Rating
| Type | Nonfeedback stereo preamplifier | ||
| Input Sensitivity / Impedance |
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| Output Level / Impedance | Tape Rec : 150mV/1k Ω Output : 1 V (rated), 5 V (maximum) / 1k Ω |
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| Power supply voltage | 100 VAC, 50Hz/60Hz | ||
| Power consumption | 60W (Electrical Appliance and Material Control Law) | ||
| AC outlet | Power switch interlock : Route 3, total 700W Power switch not linked : 2 systems, total 200W |
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| External dimensions | Width 220x Height 185x Depth 454 mm | ||
| Weight | 12.1kg |