Accuphase E 560 Brochure
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n Volume control resolutionAAVA adjusts the listening volume by means of 16 weighted V-I converter amplifi ers which are controlled by current switches. The number of possible volume steps set by the combination of these converter amplifi ers is 2 to the power of 16 = 65,536. n Input buffer amps use 5-MCS topologyOne of the factors that have a bearing on possible noise in an AAVA arrangement is the input buffer design. By connecting fi ve high-performance amps in parallel, excellent S/N ratio is assured. n AAVA maintains high S/N ratio and uniform frequency responseUnlike with conventional volume controls, AAVA does not introduce a change in impedance at any volume setting. Consequently, there is no deterioration of S/N ratio, and frequency response remains totally uniform. The benefi ts are especially apparent at settings that correspond to normal listening levels, because the tonal quality is not altered in any way. n No more left/right tracking differences or crosstalkBecause AAVA is an electronic circuit employing fi xed-value resistors, there is virtually no left/right tracking error also at low volume levels. Since channels can be kept separate, crosstalk also does not present a problem. The integrated amplifiers from Accuphase operating in full class A enjoy an excellent reputation both in Japan and overseas for their outstanding musical qualities. The E-560 represents a model change from the popular E-550. While incorporating the sophisticated technological know-how gained by Accuphase over the years, it features a further refined AAVA volume control and uses the latest cir- cuit topology and strictly selected parts of the utmost quality. The E-560 is destined to be- come the new reference model for high-class integrated amplifiers. AAVA is a revolutionary principle designed for The Ultimate Pure Class A Integrated Amplifi er – Innovative AAVA volume control and triple parallel push-pull power MOS-FET arrangement in output stage. Power amplifi er stage features latest instrumentation amplifi er confi guration for balanced signal transmission. Current feedback design combined with further improved MCS+ topology results in excellent high-range phase characteristics. Massive power supply delivers as much as 150 watts per channel (music signal) into loads as low as 1 ohm. high performance and ultimate sound. It inte- grates the amplification and volume control tasks in a single electronic entity that uses analog processing and eliminates all variable resistors from the signal path. Its performance and sonic purity do not deteriorate over the years, providing excellent reliability. The AAVA version in the E-560 takes the principle to the next level, delivering the same peerless per- formance in a more compact form factor. The power amplifier section is built as an ad- vanced instrumentation amplifier, which enables fully balanced signal transmission throughout. Together with the further improved MCS+ cir-cuit topology and the highly acclaimed current feedback principle, this makes for even better electrical characteristics. In the output stage, high-power MOS-FET devices renowned for their great sound and utter reliability are ar- ranged in a triple parallel push-pull configura- tion per channel. MOS-FETs have excellent frequency response and high input impedance which reduces the load on the preceding driver stage. They also have perfect thermal stability. By driving these devices in class A, the ampli- fier becomes capable of reproducing even the most delicate details in the music source with intriguing suppleness and utmost fidelity. AAVA (Accuphase Analog Vari-gain Amplifi er) Volume Control AAVA is a radically different volume control principle that eliminates all variable resistors from the signal path and provides top-notch performance and sound quality. Because the music signal is not affected by changes in impedance, high signal-to-noise ratio and low distortion are maintained at any volume control setting. n AAVA means analog processingThe AAVA circuit converts the music signal from a voltage into a current, switches gain by means of current switches, and then reconverts the current into a voltage. The entire process is carried out in the analog domain. n Same operation feel as a conventional high-quality volume controlThe volume control knob position is detected by a dedicated CPU which in turn selects the current switches for AAVA operation. Operating the knob therefore feels exactly the same as with a conventional control, and as before, operation via the remote commander is also possible. n Attenuator and balance control also implemented by AAVAThe functions of the attenuator and the left/right balance control are covered by the AAVA circuit as well, eliminating the need for additional circuit stages. Keeping the confi guration simple helps to maintain high performance and sonic purity. n Display shows volume level as numeric valueThe volume level (degree of attenuation) as set with AAVA is shown as a numeric indication in the center of the front panel. The indication ranges from MAX (0 dB) to MIN (lowest setting). The music signal is converted into 16 types of weighted current by V-I (voltage - current) converting amplifi ers [1/2, 1/2 2, ... 1/2 15, 1/2 16]. The 16 currents are turned on or off by 16 cur- rent switches, and the combination of switch settings determines the overall volume. The switching operation is controlled by a CPU ac- cording to the position of the volume control knob. The combined signal current forms a variable gain circuit that adjusts the volume. Finally, the combined current is converted back into a voltage by an I-V (current - voltage) converter. AAVA operation principle n AAVA volume control assembly with higher integration density of components and circuitry. n CPU assembly which controls AAVA and various other functions. AAVA confi guration in E-560 INPUT 5-MCS Buffer Input music signal Conversion into current with 16 weighting stages (1/2 - 1/2 16) 16 current switches(65,536 possible combinations) CPU detects position of volume knob and operates current on/off switches according to knob position Reconversion of current into voltage Current values are added Volume knob is turned and position is detected OUTPUT V-I ConverterI-V Converter CPU Volume Balance Attenuator
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n Power amplifi er assembly and output stage with triple parallel push-pull power MOS-FETs directly mounted to large heat sink. n Supplied remote com- mander RC-200 Allows volume ad- justment and input source switching. OUTPUT + INPUT - INPUT NFB NETWORK NFB NETWORK GAIN CONTROL CIRCUIT Bias stabilizer Bias stabilizer Bias stabilizer Bias stabilizer Multiple Circuit Summing-up MCS+ Bias stabilizer REGULATORREGULATOR Circuit diagram of E-560 power amplifi er (one channel) n Power MOS FETs in triple paral- lel confi guration operating in pure class A deliver guaranteed linear power: 120 watts/channel into 2 ohms, 60 watts/channel into 4 ohms or 30 watts/channel into 8 ohms. n Instrumentation amplifi er principle in power amplifi er section allows fully balanced signal paths. Current feedback design ensures outstanding high-range phase char- acteristics, together with further improved MCS+ topology. n Tone controls using active fi lters for optimum sound quality. n Dedicated headphone amplifi er optimized for sound quality. n Loudness compensator for enhanced bass at low listening levels. n Versatile array of inputs with two balanced in- puts to shut out external noise interference. n Logic-controlled relays assure high sound quality and long-term reliability. n Power supply with massive high- effi ciency toroidal transformer and large fi ltering capacitors provides ample reserves. n Individual phase setting supported for each input position. n Analog peak power meters for monitoring output levels. n Two sets of large-size speaker terminals accept also Y lugs. n Two option board installation slots provide further versatil- ity. With AD-20 board, MC/MM switching on E-560 front panel is possible. n EXT PRE switch and power amplifi er input connectors allow independent use of power ampli- fi er section. Gold-plated input/output jacks connected directly to relaysPower MOS-FETs Toroidal power transformer Filtering capacitors Large speaker terminals