Accuphase C-2000 Brochure

m Revolutionary AAVA volume control m Fully modular

construction with individual left/right amplifier units arranged on motherboard m Separate power transformers and filtering capacitors for left and right channels m Logic-controlled relays for shortest signal paths m High quality tone controls m Option board slots allow digital signal input and analog record playback

Innovative AAVA type volume control Adjusts listening level without

deterioration in S/N ratio or distortion. Dual mono construction with two power

transformers and separate modular AAVA amplifiers for left and right channels

mounted on motherboard. Option board slots provide support for digital input

signals and high-grade analog record playback.

The C-2000 inherits the design technology of the Accuphase C-2800 and C-2400, featuring the same AAVA type volume control. AAVA (Accuphase Analog Vari-gain Amplifier) is an innovative concept that differs radically from conventional variable-resistor type volume controls. It tackles one of the most important aspects of a preamplifier, namely how it handles listening level adjustment. In AAVA, amplification and volume control are fully unified, eliminating all mechanical contact points. Pure analog processing ensures optimum performance and superb sound. Doing away with the variable resistor in the signal path has numerous advantages and brings the

amplifier a significant step closer to absolute purity in signal transmission. Another benefit of AAVA is that it is configured only with highly reliable semiconductor components. This assures that performance and sound quality will remain undiminished for many years to come. The large volume knob on the front panel employs a position detection method that combines superb precision with a smooth conventional feel. The power transformer, filtering capacitors and all other parts of the power supply are duplicated for the left and right channel. What's more, all unit amplifiers such as for line input, balanced output, and AAVA are also entirely separate for

the two channels, arranged on a high-quality motherboard. This fully monophonic construction prevents unwanted interaction both on the electrical and the physical plane. The line amplifier with integrated volume control is a major aspect of the C-2000, but there are also a host of other attractive features in this superb analog preamplifier. Tone controls and loudness compensator allow fine tuning of the sound. Tape recorder and copying facilities as well as an EXT PRE function provide connection flexibility. A range of option boards allows the amplifier to handle digital input signals and to realize high-grade playback of analog records.

AAVA (Accuphase Analog Vari-gain Amplifier) volume control

The newly developed volume control called AAVA (Accuphase Analog Vari-gain Amplifier) is totally different from conventional controls using resistors. Because the music signal does not pass through variable resistors, it is not affected by changes in impedance. This means that high signal-to-noise ratio and low distortion of the signal are maintained. The volume can be adjusted without any deterioration in sound quality.

n Volume control resolution

AAVA adjusts the listening volume by means of 16 current switches which are operated by 16 weighted V-I converter amplifiers. The number of possible volume steps set by the combination of these converter amplifiers is 2 to the power of 16 = 65,536.

n AAVA maintains high S/N ratio and unchanged

frequency response

With conventional volume controls, the impedance increases significantly at settings that correspond to normal listening levels, thereby leading to increased noise. Because there is no change in impedance with AAVA, there is no deterioration of S/N ratio, and frequency response also is not affected. Adjusting the volume with AAVA does not mean introducing noise. High S/N ratio is maintained, and there is no alteration of sound quality.

n No more left/right tracking differences or crosstalk

Because AAVA is an electronic circuit employing fixedvalue 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.

n Simple circuit configuration

AAVA unifies the amplifier and volume control functions, resulting in a circuit that is electrically very simple. Longterm reliability is excellent, with performance and sound quality that will remain unchanged also after prolonged use.

n AAVA means analog processing

The 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 control

The 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

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.

BUFFER

INPUT

BUFFER

Input music signal

V- I Converter

Conversion into current with 16 weighting stages (1/2 - 1/216)

AAVA operates by feeding the music signal to a V-I (voltage - current) converting amplifier where it is weighted in 16 steps [1/2, 1/2 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.

16 current switches (65,536 possible combinations)

Volume Balance

CPU

Attenuator

CPU detects position of volume knob and operates current on/off switches according to knob position

AAVA operation

... 1/215, 1/216]. The 16 current steps are turned

AAVA principle

Current values are added

Modular AAVA unit contains input buffer, 16 V-I converter amps and current switches, current adder, I-V converter amp, and other circuitry on three boards, plus a CPU for AAVA control. Modules are installed separately for left/ right channel on a motherboard.

I-V Converter

Reconversion of current into voltage

VOLUME

MIN MAX

Volume knob is turned and position is detected

OUTPUT

+ 2 hidden pages