INTEGRATED AMP 90 W/CH - Triple parallel electronic volume and tone controls 

Details:
The development of the modern audio amplifier began in the 1960s with the introduction of full-transistor amplifiers. In the 1970s, pure complementary configured power amps appeared, made possible by high output PNPNPN transistors, and became the dominant type of analogue amplifier. Now digital amps have become popular for their high conversion efficiency and superior operating precision, as well as for their lower weight, size and heat production as compared to analogue amps. Some manufacturers of audiophile-quality amps are working to improve the traditional pure complementary analogue amplifier, while others are seeking to achieve higher sound quality from digital amplifiers.
But Yamaha has developed a third approach that we believe is superior to the other two. The Floating Balanced Power Amplifier uses patented technologies featuring power transistors with the same polarity at the output stage to achieve completely symmetrical operation.
First introduced in the Yamaha A-S2000, this method is also used to good effect in the Yamaha A-S1000, which combines a floating balanced power amp section with a high quality preamp section. Simpler in configuration yet with many of the same sound quality features as the ultra high-end Yamaha A-S2000, it will deliver excellent performance with the Yamaha CD-S1000 Super Audio CD Player and other high quality components.
The power amp, power supply, and phono EQ circuits that contribute to the Yamaha A-S1000's high sound quality are identical to those of the Yamaha A-S2000, while the line amp section and volume and tone circuits are nearly the same. Designed to take full advantage of the excellent sonic qualities of the matching CD-S1000, the Yamaha A-S1000 will also bring out the best of other high performance components.
With the Yamaha A-S2000 and now the A-S1000, Yamaha has taken the bold step of using a floating balanced configuration to update the power amplifier for serious music fans. This method, which is completely different from the pure complementary circuit that has been the main type used for the past four decades, features identical polarity on the plus and minus side of the output stage. By completely isolating the plus and minus sides of the left and right channels of both the NFB and power supplies, it achieves perfectly symmetrical operation in the output stage. The use of four sets of floating power supply units (not connected to earth), provides further operating precision. The result is very low levels of noise and distortion for exceptionally pure and transparent sound quality.
Conventional audio amps have the volume and tone control circuits arranged in series (in line); when the tone controls are used, the signal route becomes more complicated, which can lower sound quality. Many high quality amps therefore have a default circuit that can be selected to bypass the tone controls, but this forces you to choose between tone control and optimum quality. The Yamaha A-S2000 and A-S1000 are the first amplifiers to avoid this problem by employing triple parallel electronic volume and tone controls, providing maximum sound quality even when the tone controls are used (signal goes through fewer ICs, so there is less noise). When the tone controls are set to the centre position, the passive element used for tone control is bypassed, so the three volume elements connected in parallel operate solely to drive and control the volume, for more efficient use of the power output. Each volume element is an ultra-high quality device and an analogue potentiometer is used to provide a very smooth operating feel.
Although it is an integrated amplifier, the A-S1000 has a completely left-right symmetrical construction that makes it virtually the equal of separate amps. A central reinforcing bar ensures that the chassis is totally rigid.

  * High performance amplifier that takes full advantage of the sound quality benefits of balanced amplification

  * Floating Balanced Power Amplifier

  * Triple parallel electronic volume and tone controls

  * A-S1000 has a completely left-right symmetrical construction that makes it virtually the equal of separate amps


 
Specifications:

  * Dimensions (HxWxD) in mm       137x435x465

  * Frequency Response 1                 5Hz - 100kHz

  * Input sensitivity & impedance      150 mV/47 k ohms

  * Power output                                2 x 160 Watts

  * Signal to noise ratio              98dB

  * tone controls                             Bass, Treble

  * Total harmonic distortion       0.015%

  * Weight 22kg