Accuphase C 3800 Brochure

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Accuphase C 3800 Brochure

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Reference preamplifier for the next generation — Balanced AAVA features two AAVA circuits driven in balanced mode, realizing fully balanced operation for all signals from input to output. Total of 20 unit amplifiers for left and right channels, using printed circuit boards made from glass cloth fluorocarbon resin. Dual-mono construction with separate high-efficiency toroidal transformers providing plenty of reserves. Individual phase setting for each input position. After its founding in 1972, the first product unveiled by Accuphase was the separate amplifier pair C-200/P - 3 0 0 . E v e r s i n c e t h e n , t h e c o m p a n y h a s b e e n unwavering in its dedication to high-end audio, placing utmost emphasis on superior quality and truly faithful sound reproduction. This has resulted in the creation of products sustained by peerless technology and providing outstanding value to their owners. Each product was recognized for genuine creativity and solid reliability, with many models attaining legendary status. Both in Japan and worldwide, audiophiles continue to hold Accuphase in high esteem. The C-3800 now concentrates the extensive know-how and expertise gained over the years in the field of preamplifiers into a product that is destined to become the new reference for the next generation. Both in concept and circuit execution, this preamplifier stands at the very forefront of technology. Each and every part has been carefully selected through extended cycles of listening tests. Esche wi ng comprises in any respect, Accu phase has created the ultimate in performance and sound quality.Foremost among the distinguishing features of the C - 3 8 0 0 i s t h e f u r t h e r e v o l v e d “ B a l a n c e d A AVA ” concept. Two AAVA circuits are driven in a balanced c o n f i g u r a t i o n , r e s u l t i n g i n i d e a l v o l u m e c o n t r o l behavior from balanced input to balanced output. The complete path for all signals from the i n p u t c o n n e c t o r s t o t h e o u t p u t s i s f u l l y b a l a n c e d , e n s u r i n g u t m o s t p u r i t y a n d f u r t h e r improved electrical characteristics. The result is reflected in n o t a b l y i m p r o v e d music reproduction that takes fidelity to the next higher plane.S i n c e m a k i n g i t s d e b u t i n t h e C - 2 8 0 0 i n 2 0 0 2 , AAVA has revolutionized the concept of the analog p r e a m p l i f i e r. E a c h s u b s e q u e n t p r e a m p l i f i e r a n d integrated amplifier from Accuphase has featured AAVA technology. Both AAVA and Balanced AAVA are fundamentally different from the digital signal processing approach involving A/D and D/A conversion. The volume control operates purely in the analog domain. Using AAVA to change the volume means that the high S/N ratio and low distortion of the amplifier remain totally unaffected. Frequency response and sound quality do not suffer at any listening level. There are no left/right tracking differences or crosstalk, and no other performance related degradations. The conventional concept of volume control is well and truly a thing of the past. Another benefit of AAVA is the fact that it consists entirely of highly reliable semiconductor parts, so that performance and sound quality will remain undiminished for many years to come. Balanced AAVA (Accuphase Analog Vari-gain Amplifier) Volume Control Regular AAVA Balanced input Balanced AAVA Balanced input Unbalanced output Balanced output n Powerful current feedback amplifier in AAVA input stageThe input stage employs four MCS+ current f e e d b a c k a m p l i f i e r s i n a n i n s t r u m e n t a t i o n amplifier configuration, featuring outstanding high-speed, low-noise operation. n 36 V-I converter amplifiersBecause Balanced AAVA adopts a completely b a l a n c e d c u r r e n t s o u r c e c o n f i g u r a t i o n , 1 6 amplifiers each are used for the + input and - input, with the V-I amplifiers for the upper two bits being paralleled, resulting in a total of 36 amplifiers. This ultra-low noise current source contributes to further improved S/N ratio. n Volume control resolutionAAVA 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. n A AVA e n s u r e s h i g h S / N r a t i o , l o w d i s t o r t i o n , a n d u n i f o r m f r e q u e n c y r e s p o n s e a n d s o u n d q u a l i t y a t a n y volumeBecause AAVA does not introduce a change in impedance, there is no deterioration of S/N ratio at any practical volume setting, and frequency response remains totally uniform. The sound is always perfectly transparent and the tonal quality is not altered in any way. n No more left/right tracking differences or crosstalkBecause the channels can be kept separate, there is virtually no left/right tracking error also at very low volume levels, and crosstalk does not present a problem. n AAVA means analog processingThe AAVA circuit converts the music signal from a voltage into a current, alters 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 Amplifier display shows accurate gain n A t t e n u a t o r a n d l e f t / r i g h t b a l a n c e control also implemented by AAVA AAVA is a radically different volume control principle that eliminates all variable resistors from the signal path. The C-3800 employs two AAVA modules in a fully balanced configuration from input to output. This makes it possible to realize fully balanced signal paths throughout the preamplifier , extending from the input connectors to the outputs. Operation Principle of Balanced AAVA in C-3800 V-I Converter V-I Converter I-V Converter • Volume• Balance• Attenuator CPU controls current on/off s w i t c h e s s o t h a t v o l u m e level matches knob position OUTPUT OUTPUT INPUT INPUT High Voltage Current Feedback Amplifier High Voltage Current Feedback Amplifier Conversion into current with 16 weighting stages (1/2 - 1/2 16) 16 current switches (65,536 possible combinations) Conversion into current with 16 weighting stages (1/2 - 1/2 16) 16 current switches (65,536 possible combinations) Current values are added R e c o n v e r s i o n o f current into voltage Current values are added R e c o n v e r s i o n o f current into voltage Volume level display Vo l u m e k n o b i s t u r n e d and volume level position is detected Balanced Output Balanced Input I-V Converter