Bow Technologies ZZ-One
¥ 460,000 (Released in September 1995)
¥ 520,000 (after price revision, around 2000?)
Commentary
A dual-monaural integrated amplifier designed for simplicity.
In addition to the dual monaural circuit configuration, the toroidal transformer of the power supply section is arranged on each of the left and right channels to ensure channel separation.
The power supply section uses a high-speed, low-impedance electrolytic capacitor and a rectifier with excellent recovery, and is designed to be highly efficient by bypassing it with a high-grade polypropylene capacitor.
A low-noise J-FET transistor and a high-voltage / high-speed bipolar transistor with strict characteristic matching are used at the front end of the amplifier section by cascode connection, and high-speed voltage amplification is achieved by stable operation at a constant voltage. The next stage is coupled with a power MOS-FET and equipped with a buffer block that amplifies only unity gain as a source follower. The output stage is composed of a single push-pull MOS-FET.
In addition, pure reproducibility is pursued by a non-NFB configuration that does not use NFB. Bow Technologies eliminates NFB by ensuring the linearity of each element and each circuit through careful handcraft and careful selection of parts including those for military use.
By using only temperature sensors for detecting overcurrent and overheating as the protection circuit of the amplifier section, the noise interference factor is eliminated.
The front panel has a simple configuration with only a gold-finished input selector and volume control, and three push buttons for monitor / expander / standby.
The input source is designed to light up inside the black acrylic.
Equipped with an expansion function, two types of input gain can be selected with the push button.
Normally, the full gain of the amplifier is used by setting the expansion button to ON. Also, if you want to control the volume finely even when playing at a small level, set it to off. When off, the gain setting is about 15 dB lower than usual. In addition, by switching according to the gain of the connected source, the volume can always be adjusted using the best part of the volume element, so that superior sound quality and resolution can be maintained.
The ZZ-One uses the volume as a passive variable resistor connected to the ground. By limiting its role to attenuation, it solves the problem that the quality of the device affects the sound quality. In this case, an extremely expensive volume element is required.
Model Rating
| Type | Pre-main amplifier |
| Effective power | 75W + 75W (8 Ω, 20 Hz to 20 kHz) |
| Input sensitivity | 0.5V |
| Input impedance | 3.4k Ω |
| Output impedance | 2.5 Ω |
| Distortion factor | 0.5% squid |
| Bandwidth | 3 Hz to 50 kHz -3dB |
| Signal-to-noise ratio | 110dB(A-WTD) |
| Slew rate | 10 V / μ s |
| Rise time | 7 μ s |
| Channel balance | 0.5 dB or less |
| Power consumption | 500W maximum 50W (idle) |
| External dimensions | Width 430x Height 80x Depth 390 mm |
| Weight | 16kg |
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