●Revolutionary AAVA volume control ● Output stage with high-power transistors in parallel push-pull arrangement delivers high quality power: 90 watts x 2 into 8 ohms ● Instrumentation amplifier principle for power amplifier input stage allows fully balanced signal transmission
●Logic-control relays for shortest signal paths ● Strong power supply with massive high-efficiency transformer and large filtering capacitors ● EXT PRE button allows separate use of preamplifier and power amplifier sections ● Numeric indication of volume level
Integrated amplifier with AAVA volume control − Power amplifier section featuring high-power transistors in parallel push-pull configuration, together with robust power supply, realizes low impedance in output stage. Rated for 90 watts of quality power into 8 ohms, with damping factor of 200. Current feedback amplifier topology assures excellent phase characteristics in high range, and instrumentation amplifier principle enables fully balanced signal transmission.
The Accuphase E-200 series of integrated amplifiers occupies a central position in the Accuphase lineup, and enjoys enduring popularity both in Japan and abroad. The E-260 stands firmly in this tradition, harnessing the technology advantages of the series in a new format. It represents a major overhaul of the E-250, reflecting latest design technology and featuring the same advanced AAVA volume control as the higher-ranked models E-560, E-460, and E-360. The result is a classy integrated amplifier that brings out the full musical splendor of every source. AAVA is a revolutionary principle that redefines the concept of volume control from the ground up, operating purely in the analog
domain for high performance and ultimate sound. Starting with the ultimate, top-of-the- line preamplifier C-3800, it has received high praise as a crucial ingredient for sonic excellence in preamplifiers and integrated amplifiers.
The preamplifier and power amplifier sections of the E-260 are separate circuits that rival discrete components in performance and sound. With a simple flick of the EXT PRE switch, the preamplifier can be detached from the power amplifier, allowing the sections to be used individually.
The power amplifier block is configured as an advanced instrumentation amplifier, which enables fully balanced signal transmission
throughout. Together with the highly acclaimed current feedback principle, this makes for even better electrical characteristics. In the output stage, high-power audio grade transistors are arranged in a parallel push-pull configuration which significantly enhances the capability to safely drive low-impedance loads.
Output operation is sustained by the power supply with a massive power transformer and large filtering capacitors. This provides high-quality power output of 115 watts x 2 into 4 ohms or 90 watts x 2 into 8 ohms, along with a damping factor of 200, thanks to the redesigned circuitry.
AAVA (Accuphase Analog Vari-gain Amplifier) Volume Control
AAVA is a radically different volume control principle that eliminates all variable resistors from the signal path and uses analog processing to provide top-notch performance and sound quality. Because the music signal is not affected by changes in impedance due to variable resistors, high signal-to-noise ratio and low distortion are maintained at any volume control setting.
■Volume control resolution
AAVA adjusts the listening volume by means of 16 weighted V-I converter amplifiers which are controlled by current switches. The number of possible volume steps set by the combination of these converter amplifiers is 2 to the power of 16 = 65,536.
■Input buffer amps use 5-MCS topology
One of the factors that have a bearing on possible noise in an AAVA arrangement is the input buffer design. By connecting five high-performance amps in parallel, excellent S/N ratio is assured.
■AAVA maintains high S/N ratio and uniform frequency response
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 benefits are especially apparent at settings that correspond to normal listening levels, because the tonal quality is not altered in any way.
■No more left/right tracking error or crosstalk
Because AAVA is an electronic circuit employing fixed-value resistors, there are virtually no left/right tracking differences even at very low volume levels. Since channels can be kept separate, crosstalk also ceases to be a problem.
■AAVA means analog processing
The AAVA circuit converts the music signal from a voltage into a current, controls gain by means of current switches, and then reconverts the current into a voltage. The entire process is carried out in the analog domain.
■Same operation feel as a conventional high-quality volume control
Operating the volume knob feels exactly the same as with a conventional control, and as before, operation via the remote commander is also possible.
■Attenuator and balance control also implemented by AAVA
The 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 configuration simple helps to maintain high performance and sonic purity.
■Display shows volume level as numeric value
The 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).
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16 current switches |
AAVA configuration in E-260 |
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(65,536 possible combinations) |
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1 |
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2 |
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1 |
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I-V Converter |
22 |
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Reconversion of |
Input music signal |
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current into voltage |
1 |
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23 |
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Current |
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BUFFER |
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I - V |
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INPUT |
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OUTPUT |
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5-MCS |
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values are |
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added |
LEVEL DISPLAY |
1 |
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215 |
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1 |
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216 |
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V- I Converter |
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Volume |
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CPU |
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Balance |
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Attenuator |
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Conversion into current |
CPU detects position of volume knob |
Volume knob is turned |
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with 16 weighting stages |
and operates current on/off switches |
and position is detected |
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(1/2 - 1/216) |
according to knob position |
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AAVA operation principle
The music signal is converted into 16 types of weighted current by V-I (voltage - current) converting amplifiers [1/2, 1/22, ... 1/215, 1/216]. The 16 currents are turned on or off by 16 current switches, and the combination of switch settings determines the overall volume. The switching operation is controlled by a CPU according 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.
■CPU assembly for control of AAVA and various other functions
■AAVA volume control assembly with higher integration density of components and circuitry
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