For faithful reproduction of high-quality digital sources, an amplifier must be able to handle extremely delicate low-level signals and thunderous high-impact peaks with equal aplomb. It should not be affected by fluctuations in speaker load, and operation should remain stable at all times. The P-700 perfectly fulfills aII of these requirements. Even difficult speakers that present not only a resistive but also a reactive load to the amplifier can be driven with ease and authority. ln the output stage, a total of twelve multi-emitter type wide-range power transistors are arranged in a push-pull configuration, resulting in impressive output ratings. By using the P-700 as a monaural amplifier in bridged mode, even higher output can be achieved.

The amplifying circuitry of the P-700 features the current feedback principle which combines superb sonic qualities with extraordinary stability of operation and excellent frequency response characteristics. This circuit requires only minimal phase compensation in the high frequency range, and NFB can be kept desirably low. The audible result is drastically improved transient response.

In the power supply section, which acts as the energy source for the amplifier, a high-efficiency "super Ring'- toroidal transformer is used, in combination with Barge filtering capacitors. This gives the P-700 ample performance margins to handle even the most severe demands. Balanced inputs make the amplifier impervious against externally induced noise during signal transmission. Gold plating of all major parts which carry the music signal, including circuit board copper traces and input and output connectors is another example ofthe P-700's dedication to musical purity.

The large heat sinks protruding on both sides of the amplifier and the panels of 15 mm thick extruded aluminum with champagne-gold alumite finish make the P-700 afeast not only to the ear butto the eye as well. This new reference model exudes an atmosphere of sheer competence and beautiful sophistication which isfully borne out in the music as heard through this masterpiece. This is pure audio at its best.

Conventional amplifiers employ voltage NFB, whereby the output voltage is used for the feedback loop. In the P-700 however, the signal current rather than the voltage is used for feedback. Figure 3 shows the operating principle of this circuit. At the sensing point ofthe feedback loop, the impedance is kept Bow and current detection is performed.

An impedance-converting amplifier then transforms the current into a voltage to be used as the feed-back signal. Since the impedance at the current feedback point (current adder in Figure 3) is very low, there is almost no phase shift. Phase compensation can be kept to a minimum, resulting in excellent transient response and superb sonic transparency with natural energy distribution.

Figure 4 shows frequency response for different gain settings of the current feedback amplifier. The graphs demonstrate that response remains uniform over a wide range.