m Revolutionary AAVA volume control m Printed circuit boards using
Teflon base with low dielectric constant and low loss m Separate
R-toroidal transformers for left and right channels m Fully modular
construction with individual amplifier units for each stage m Logiccontrolled relays for shortest signal paths m Optional analog record
playback capability m Massive cabinet of natural persimmons wood

The analog preamplifier has just been redefined
Revolutionary AAVA
type volume control. Fully modular construction with Teflon-based printed
circuit boards. Dual mono configuration with separate R-toroidaltransformers for left and right channels. Optional dedicated phono equalizer
unit allows analog record reproduction with superb fidelity.

The two most basic tasks of a preamplifier are
selecting the input source and adjusting the volume.
How the volume adjustment is achieved has asignificant bearing on sound quality. The C-2800
introduces a novel concept called AAVA (Accuphase
Analog Vari-gain Amplifier). This circuit differs radicallyfrom conventional variable-resistor type volume
controls. Amplification and volume control are fully
unified, eliminating all mechanical contact points. Pureanalog processing ensures optimum performance andsuperb sound. Doing away with the variable resistor
in the signal path has numerous advantages andbrings the amplifier a significant step closer toabsolute purity in signal transmission.
The power transformer, filtering capacitors and allother parts of the power supply are duplicated for theleft 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 monaural
construction prevents unwanted crosstalk andinteraction both on the electrical and the physicalplane. The result is utterly stable playback sound of
impeccable quality. Logic relay control is used forsource switching to implement the shortest possible
signal paths. The printed circuit boards are an
important element of a preamplifier both regarding
electrical performance as well as sound quality. In theC-2800, these are made from a Teflon material (glassfluorocarbon resin) with low dielectric constant andminimum loss. Each and every part used in this topnotch analog preamplifier has been carefully selectedon the basis of sonic performance. The overall result
is a flagship product that represents the best thatAccuphase has to offer.
* Teflon is a registered trademark of DuPont USA.

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. It allows
precise listening level adjustment while maintaining top-notch performance and sound quality over the entire range. Because the music signal does not passthrough 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.
Internally, a dedicated CPU selects the current switches that determine the gain of the amplifier. With regard to the music signal, the AAVA circuit is a fully analog
volume control.
n Simple circuit configuration
AAVA unifies the amplifier and volume control functions, resulting in a circuitthat is electrically very simple. Right and left channels are fully independent,
and frequency response does not change regardless of the volume control
knob position. Channel separation is excellent, and sonic performance remains
totally uniform over the entire range.

n AAVA operation principle
AAVA operates by feeding the music signal to a V-I (voltage - current) converter
where it is weighted in 16 steps [1/2, 1/22, ... 1/215, 1/216]. The 16 current steps
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 volume. Finally, thecombined current is converted back into a voltage by an I-V (current - voltage)
converter.

n AAVA means analog processing
The 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 avoltage.

n AAVA resolution
AAVA adjusts the listening volume by means of 16 current switches. The
number of possible volume steps set by the combination of these switches is
2 to the power of 16 = 65,536. When maximum output voltage is 5 V, resolution
is an amazing 0.07 mV.

n Same operation feel as a conventional high-quality volume control
The actual volume control knob is linked to a variable resistor. However, thisresistor is only used to detect the absolute position of the knob. Operating thecontrol therefore feels exactly the same as with a conventional control, andoperation via the remote commander is also possible.

n Minimal distortion and no thermal noise
Because AAVA is an electronic circuit, the music signal does not pass throughany variable resistors. Thermal noise caused by resistors is totally absent.
Because there is no impedance that affects the signal, S/N ratio remains at
the logical optimum. The circuit configuration also assures ultra-low distortion.

n Attenuator and balance control also realized via AAVA
The functions of the attenuator and the left/right balance control are coveredby the AAVA circuit as well, eliminating the need for additional stages. Keeping
the configuration simple helps to maintain high performance and sonic purity.

16 current switches(65,536 possible combinations)

Reconversion ofcurrent into voltage

Current
values areadded

Input musicsignalConversion into current
with 16 weighting stages(1/2 - 1/216 )Fig. 1 AAVA Principle

CPU controls current
switches according to knob
position

Position detection of
volume control knob

AAVA unit amplifier (one channel). PCB employs
Teflon and gold-plated copperSeparate unit amplifiers for left/right mounted on
sturdy 8-mm aluminum chassis
The C-2800 contains a total of 18 unit amplifiers,
comprising modules for input buffer, AAVA circuit,balanced output, etc. These units are housed in solid
enclosures made of sturdy 8-mm thick aluminum andmounted to a glass epoxy motherboard. This prevents
electrical interference and guards against mechanicalvibrations.
Logic-controlled relays assure high sound quality
and long-term reliability
The strategically placed relays of the C-2800 prevent
any signal degradation that could occur if the signal
has to travel a long way for input and output connection
and function switching. Optimum signal flow ismaintained at all times.

Ideal power supply uses newly developed"R-toroidal transformers" in fully monaural
configuration
The power supply not only serves as the energy
source of an amplifier, the quality of the current
supplied to the various loads also has a considerable
bearing on sound quality. In the C-2800, newly
developed R-toroidal transformers and dedicatedfiltering capacitors are used for each of the two stereo
channels, resulting in a fully monaural construction.
The R-toroidal transformer uses a core with a circularcross-section designed to reducen Supplied remotecommander RC-32
allows volume control
and input source
selection

magnetic
losses andimprovee f f i c i e n c y.
Leakage flux
is vir tuallyabsent. The
transformer ishoused in adual-wall
enclosurewith a glass
fiber core andstrong resin coating. Epoxy filler with superior
vibration-damping characteristics is used to further
isolate the transformer, resulting in highly effective
triple insulation.
Printed circuit boards made from Teflon with low
dielectric constant and low loss
The printed circuit boards for the signal-carrying
circuits are made of Teflon, a glass fluorocarbon
resin material. Teflon has extremely low
specific inductive capacity which isdesirable for fast signal transmission
and a low dielectric dissipation
factor which results in minimaltransmission losses. Highfrequency characteristics
and heat resistance
are also excellent.
Forfur ther
improved soundquality,
thecopper foil side isgold plated.

n Switchable preamplifier gain: 12/18/24 dB(standard position 18 dB)
n Versatile array of inputs and outputs (characterlabel display for inputs)n Dedicated headphone amplifier optimized forsound quality
n EXT PRE function allows use of external
preamplifiern Useful range of functions
m Provisions for recording/playback/copying with tworecorders
m Loudness compensator augments bass and treble
at low listening volume
m Phase selectorm Attenuatorm Subsonic filter removes ultra low frequency noisen Massive cabinet of natural persimmons woodDedicated Phono Equalizer Unit AD-2800 (Optional)
Analog records can be reproduced by installing the dedicated phono equalizer unit AD-2800 in a rearpanel slot. The AD-2800 uses printed circuit boards made from Teflon material (glass fluorocarbon resin)
and is housed in a sturdy aluminum case for complete protection against any external interference. Highly
reliable DIN connectors make the shortest possible connection between input and amplification circuits, toassure outstanding S/N ratio.

Input

OutputDC servo amplifiern Front panel

30/36 dB, switchable( Gain:Input impedance: 47 kilohms

MC

62/68 dB, switchable(Gain:
Input impedance: 10/30/100 ohms, switchable✽ The phono equalizer units AD-290 and AD-290V
designed for the Accuphase models C-290 andC-290V can also be used in the C-2800.
✽ The AD-2800 can also be used in the Accuphasemodels C-290 and C-290V.

Equalizer
elements

Circuit diagram of phono equalizer
unit AD-2800 (one channel)

MMGUARANTEED SPECIFICATIONS✽ Guaranteed specifications are measured according to EIA standard RS-490. ✽ AD stands for"Analog Disc" ✽ Specifications are shown for phono equalizer unit AD-2800 installed.
m Frequency Response

BALANCED INPUT/UNBALANCED:AD INPUT: [MM/36 dB, MC]:AD INPUT: [MM/30 dB]:m Total Harmonic Distortion

03 ~ 200,000 Hz
20 ~ 020,000 Hz
20 ~ 020,000 Hz
20 ~ 020,000 Hz+0 dB –3.0 dB+0 dB –0.2 dB±0.2 dB±0.3 dB

0.005% (for all inputs)

m Input Sensitivity, Input ImpedanceInput
AD:MM/30 dB INPUT
AD:MM/36 dB INPUTAD:MC/62 dB INPUTAD:MC/68 dB INPUTBALANCED/UNBALANCED

Pressing this button gives
access to the sub paneln Rear panel
Expansion slot for
AD-2800

m Rated Output Voltage,
Output Impedance

Input impedance
47 kΩ
47 kΩ
10/30/100 Ω, switchable
10/30/100 Ω, switchable
40 kΩ/20 kΩ

BALANCED/UNBALANCED OUTPUT:
2 V, 50 ohms
REC (with AD input):
252 mV, 200 ohms

m Signal-to-Noise Ratio
Input terminal
AD:MM/30 dB INPUT
AD:MM/36 dB INPUTAD:MC/62 dB INPUTAD:MC/68 dB INPUTBALANCED/UNBALANCED

0A Input Selector
LINE3 LINE2 LINE1 LINE-BAL CD-BALCDTUNER AD1 (OP) AD2 (OP)B Output Selector
EXT PRE ALL BAL UNBAL OFF
C Function Display
D Recorder Selector
21SOURCEREC OFFE Copy Selector 1 ➝ 2OFF2➝1F Analog Disc Equalizer Gain Selector
MM/30 dB MM/36 dB
MC/62 dB MC/68 dB
G Input Display
H Balance Control
I Volume Control
J Power Switch
K Output Phase Selector Button
L Stereo/Mono Mode Selector Button
M Subsonic Filter Button

N Loudness Compensator Buttons
OFF12O MC Cartridge Load Impedance Selector
Buttons
P Headphone Jack
Q Attenuator Button
R Line Input Jacks
CD TUNER
LINE1, 2, 3
S Recorder Input/Output Jacks
T Unbalanced Output Jacks
21 External Preamplifier Input JacksU(Unbalanced)
22 Gain Selector 24 dB
U
18 dB
12 dB
23 CD/LINE Balanced Input Connectors
Ua Groundb Inverted (–)
c Non-invert (+)
24 Balanced Output Connectors (OUTPUT 1, 2)
U
25 External Preamplifier Input Jacks (Balanced)
U
26 AC Inlet 0URemarks
0 This product is available in versions for 120/230 V AC. Make sure that the voltage shown on
the rear panel matches the AC line voltage in your area.
0 The shape of the AC inlet and plug of the supplied power cord depends on the voltage rating
and destination country.

n Supplied accessories:

Sensitivity
For rated output For 0.5 V output
8.0 mV
2.0 mV
4.0 mV
1.0 mV
0.2 mV
0.05 mV
0.1 mV
0.025 mV
252 mV
63 mV

Input shorted, IHF-A weighting
S/N ratio at rated output
95 dB
89 dB
80 dB
75 dB
111 dBS/N ratio (EIA)
91 dB
92 dB
87.5 dB
88.5 dB
110 dBm Maximum Output Level

BALANCED/UNBALANCED OUTPUT: 7.0 V
REC (with AD input):
6.0 V

m LINE maximum input level

BALANCED/ UNBALANCED INPUT:

6.0 V

m Maximum AD Input Level(0.005% THD)MM [30/36 dB] INPUT:
MC [62/68 dB] INPUT:

300 mV/150 mV
7.5 mV/3.75 mVm Minimum Load Impedance

BALANCED/UNBALANCED OUTPUT: 600 ohms
REC:
10 kilohms

m Gain (gain selector: 18 dB) ✽ Gain switch positions: 12/18/24 dB
BALANCED/UNBALANCED INPUT ➝ BALANCED/UNBALANCED OUTPUT:UNBALANCED INPUT ➝ REC OUTPUT:
AD (MM 30/36dB) INPUT ➝ BALANCED/UNBALANCED OUTPUT:
AD (MM 30/36dB) INPUT ➝ REC OUTPUT:
AD (MC 62/68dB) INPUT ➝ BALANCED/UNBALANCED OUTPUT:
AD (MC 62/68dB) INPUT ➝ REC OUT:
m Loudness Compensation

1: +3 dB (100 Hz), 2: +8 dB (100 Hz)

m Subsonic Filter

10 Hz: –18 dB/octave

18 dB
0 dB
48/54 dB
30/36 dB
80/86 dB
62/68 dB

+6 dB (20 kHz)m Attenuator–20 dBm Headphone Jack

Suitable impedance: 8 - 100 ohms

m Power Requirements

AC 120 V / 230 V, 50/60 Hz (Voltage as indicated on rear panel)m Power Consumption

48 watts

m Maximum Dimensions

Width:Height:Depth:

m Weight

21.2 kg (46.7 lbs) net (22.1 kg with AD installed)
28.0 kg (61.7 lbs) in shipping carton

477 mm
156 mm
412 mm(18-3/4")(6-1/8")(16-1/4")• AC power cord
• Audio cable with plugs (1 m)• Remote commander RC-32• Specifications and design subject to change without notice for improvements.

http://www.accuphase.com/G0205Y

PRINTED IN JAPAN 851-0127-00 (AD1)