m Preamplifier and power amplifier with MCS topology m Parallel push-pull output stage delivers high quality 100 watts × 2 into 8 ohms m Current feedback principle combines superb sound with total operation stability m Logic-control relays permit straight and short signal paths m Tone control circuits m Strong power supply with large transformer m Option board slots provide capability for digital signal input and analog record playback
Sophisticated MCS topology assures outstanding S/N ratio Enjoy crystal clear sound emerging from a background of utter silence. Current feedback amplification, wide-band power transistors in parallel push-pull configuration,
and potent power supply deliver plenty of quality power: 140 watts per channel into 4 ohms or 100 watts into 8 ohms. Option boards allows digital signal input or analog record playback with impeccable quality.
Both the preamplifier (Figure 1) and power amplifier (Figure 2) employ the MCS (Multiple
Circuit Summing) topology developed by
Accuphase. This design results in significantly improved performance characteristics such as higher S/N ratio and lower distortion. In the
E-308, the same signal is supplied to two separate amplification circuits, which also receive the feedback signal. The output of the circuits is combined, which is equivalent to parallel operation of the overall circuit.
Mathematically, when using two parallel circuits,
the improvement in S/N ratio is 3 dB. The circuit
more conventionally used voltage is used for feedback. Because there is almost no phase shift, phase compensation can be kept to a minimum, resulting in excellent transient response and superb sonic transparency. Also,
frequency response r e m a i n s uniform over a wide gain range. This is evident from
Figure
4
Frequency
(High)
which shows Fig. 4 Frequency response with current feedback f r e q u e n c y (Response remains uniform also when gain changes)
response for different gain settings of the current feedback amplifier.
(Large)
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