● Revolutionary low-noise "Balanced AAVA Volume Control" ● High-rigidity,
high-accuracy volume knob sensor mechanism ● Separate high-efficiency
toroidal power transformers for left and right channels ● Selectable preamp
gain ● Fully modular construction with separate left/right units for each amplifier
stage ● Logic-controlled relays for shortest signal paths ● Independent phaseselection for each input position ● Printed circuit boards made from glass cloth
fluorocarbon resin ● Massive wood cabinet with natural grain finish

The Ultimate Analog Preamplifier — Balanced AAVA, the supreme volume control
system from Accuphase, provides incredible smoothness and complete mastery over themusic reproduction process. Outstanding signal/noise ratio prepares the stage for thesource to emerge with breathtaking realism, conveying a wealth of acoustic detail suchas hardly ever experienced before. The C-3850 represents the pinnacle of 45 years ofAccuphase excellence in analog preamplifiers.
Having been founded in 1972, Accuphase commemorated
its 40th anniversary by releasing a next-generation beaconmodel, the Precision Stereo Preamplifier C-3800. It marked
a major milestone and was highly lauded by audiophiles
around the world as a tour de force in technologicalexcellence, performance, and sound quality. The new
Precision Stereo Preamplifier C-3850 continues thechallenge and raises the bar even further, bringing
together the entire wealth of preamplifier know-how gainedby Accuphase over the years. In construction as well as
circuit design, it incorporates latest technology realizedwith components selected through a thorough review
process including extended listening tests. The result is anaudio instrument that admits no compromise in the pursuitof peerless performance for musical mastery.
Conventional volume controls attenuate the input signal byintroducing a resistance (either using a rotary variable
resistor or fixed resistors) in the signal path, and thenamplifying the result. This makes it inevitable that–alongwith attenuation–information will be lost and noise will
increase at the lower volume level settings that arenormally used. By contrast, AAVA does not "turn down" thevolume in the ordinary sense. Rather, it switches a
combination of V-I amplifiers as required in order to directly
change the amplifier gain and thereby achieve the desired
volume. This revolutionary approach eliminates impedancechanges as well as adverse effects from noise and otherfactors. Because there is almost no increase in noise, S/Nratio does not suffer at any listening level including theimportant moderate volume settings. Frequency response
remains uniform and sound quality always maintains its fullexcellence. The C-3850 features a further evolved versionof this principle, called "Balanced AAVA", with two AAVA
circuits driven in a parallel balanced configuration. This
results in ideal volume control behavior from balanced
input to balanced output. In addition, the volume knob andsensor mechanism fashioned with utmost precision from asingle highly rigid aluminum block provides silky smooth
operation with excellent tactile feel, and also improves thequietness of motor-driven operation. The entire path for all
signals from the input connectors to the outputs is fullybalanced, and signal purity is further elevated by the use ofultimate-quality parts and materials, ensuring electricalcharacteristics and sonic excellence of the highest order.
With its no-holds-barred use of resources, and its bold
realization of latest circuit design, the C-3850 is an analog
preamplifier that redefines the state of the art and points
the way towards the future.

Balanced AAVA (Accuphase Analog Vari-gain Amplifier) Volume Control

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

Operation Principle ofBalanced AAVA in C-3850

16 current switches
216 = 65,536
possible combinations

1−

V- I Converter
2
1−High Voltage
Current Feedback
Amplifier22

4-parallel

AAVA Operation Principle
The music signal is converted into 16 types of weighted current by V-I(voltage-to-current) converting amplifiers, as shown in the illustration below.
The 16 currents are turned on or off by 16 current switches, and the
combination of switch settings determines the overall current. The resulting
current forms a variable gain circuit that adjusts the volume of the music signal.
The respective currents are combined and converted back into a voltage by an
I-V (current-to-voltage) converter before being sent to the subsequent stage.
0.5

I-V Converter

2-parallel

Graphic representation of 16 types of V-I
converter amplifiers and resulting currents

Reconversion of current into voltage

1−＋Current values

28

0.4

are added

Current
ratio

1−

1−

0.3

215

LEVEL DISPLAY

216

0.2

+ INPUT+ OUTPUT

Balanced
Input

0.1

28

29

8

9

1−

27

7

1−

26

6

1−

25

5

1−

24

4

1−

23

3

1−

22

2

1−

1−

1−

1−

1−

1−

1−

2

1

2 10

2 11

2 12

2 13

2 14

2 15

2 16

16 types of V-I

10 11 12 13 14 15 16 converters

1−– Extruded from solid aluminum block –High-rigidity volume sensor construction

215
1−

＋

28

BALANCE ATTENUATOR
Current values
are added

I-V Converter

1−
22

1−

1−

216

0

1−

VOLUME
Volume knob is turned and volume– OUTPUT
level position is detected

V- I Converter

1−High Voltage
Current Feedback
Amplifier

These V-I converters handling minutecurrent levels enable extremely
delicate volume control.

Balanced
OutputCPU

1−– INPUTCPU controls current on/off
switches so that volumelevel matches knob position

2-parallel

2

4-parallel

Reconversion of current
into voltage

Turning the volume knob on the front
panel causes the actual volume level
position to be detected. The corresponding signal is sent to a CPU
which in turn controls the current
switches and thereby the gain of the
AAVA circuitry. The massive knob
extruded from a solid aluminum blockand mounted on large-diameter shaft
has exactly the right amount ofinertia. Together with the low-friction
internal mechanism this provides asilky smooth operation feel and also
allows extremely quiet motor-driven
operation.
★Cutaway model of volume sensor mechanism■ Upper two V-I converter amplifiers feature a special
configuration, with 4-parallel operation for the topmost and2-parallel operation for the second level, resulting in lower
impedance and an amazing S/N ratio improvement of 2 dB.
■ No more left/right tracking differences or crosstalk.
■ Amplifier display shows accurate gain as numericindication.
■ High S/N ratio, low distortion, uniform frequency response
and optimal sound quality maintained at any volume setting.
■ Attenuator and balance control also implemented by AAVA,
eliminating additional circuitry.
■ High-resolution volume control: Combination of V-I converter amplifiers gives 65,536 possible volume steps.
The amplification circuitry of C-3850 consists of a total of 18 unit amplifiers,
including I-V assembly, AAVA circuitry, balanced input and balanced
output amplifiers.

The Essence of Technology

The Beauty of Tradition

Precision Stereo Preamplifier
As the ultimate analog preamplifier, the C-3850 has been
honed to perfection, bringing together sophisticatedtechnology and carefully selected materials in a package ofrefined visual appeal. The gold-hue front panel and theexquisite wood cabinet reflect true craftsmanship, as thenatural wood grain of each individual unit has been
mirror-finished by expert hands. The result is a product thatexudes a graceful and dignified atmosphere.

Features and Functions■ Ideal power supply design realizes dual mono construction with newly
developed high-efficiency toroidal transformers and filtering capacitors(10,000 µF x 12) selected for sound quality.
■ Logic-controlled relays for signal switching assure high sound quality andlong-term reliability.
■ Versatile arrangement of line and balanced input and output connectors.
■ Printed circuit boards for signal transmission are made from glass cloth
fluorocarbon resin with low dielectric constant and minimum loss.
■ Selectable preamplifier gain with three settings (12 dB, 18 dB, 24 dB).
■ EXT PRE function allows use of external preamplifier.
■ Output phase selectable individually for each input, with visual indication.
When INV LED is lit, output phase is inverted. When LED is out, phase isnormal.
■ Dedicated headphone amplifier with three selectable gain settings.
■ Advanced High Carbon cast iron insulator feet with superior damping
characteristics further enhance sound quality.
■ Massive wood cabinet with natural grain finish.
■ More versatile features:
Provisions for recording and playback with a recorder.
Attenuator (-20 dB).
● Loudness compensator with three selectable characteristics
enhances low end presence.
● Alphanumeric indication of input position.
● Large, easy to read numeric indication of volume levelsetting.

High-efficiency toroidal power transformers

Audio quality filtering capacitors

Assembly with line level and balanced
input and output connectors

Parts selected for high sound quality and reliability●●

Phase selector button EXT PRE phase setting indication

Gain selector■ Unit amplifier assembly
A total of 18 unit amplifiers handle the signaltransmission for the left and right channel.
The printed circuit boards are made fromglass cloth fluorocarbon resin, and thecopper foil surfaces are gold-plated. The unit
amplifiers are mounted on a glass epoxy
motherboard, and left and right sections are
kept completely separate. An 8 mm thickframe made of hard aluminum prevents
mutual interference by providing electricalshielding and suppressing physical vibrations.
■ Supplied remote commander RC-210
Allows volume adjustment, input
source switching, andother operations.

EXT PRE selector

Headphonelevel selector

Ultra high performance
operational amplifiersBlock Diagram
LEFT
CHANNEL

Balanced AAVA

LINE (AD)LINE AMPLIFIER(Balanced Accuphase Analog Vari-gain Amplifier)

TUNER

FEEDBACK

CD–

LINE 1+–INPUT
SELECTOR

LINE 2
LINE 3PLAY

BAL (AD)

CPU
BAL 1

–

COMP 1,2,3

EXT PREEXT PRE

–

+

BAL 1

OUTPUT+

FEEDBACK–+RECORDER

RECORDER

LINE 2LEFT
CHANNELOUTPUTS+FEEDBACK

VolumeBalance
Attenuator–

REC

LINE 1FEEDBACK–BAL 2OUTPUT

COMP

+

PHASE

LEFT
CHANNELINPUTS
CD-BALEXT PRE+BAL 2

OUTPUT

FEEDBACKBALANCEDAMPLIFIER

COMP

LINE
BAL

+

PLAY

FEEDBACK––HP GAIN+

RIGHT
CHANNELHEADPHONE
OUTPUT

+

–

MONO

LEFT
CHANNEL
EXT PREINPUTSOUTPUT
From RIGHT CHANNELHEADPHONEAMPLIFIER

Same as LEFT CHANNEL

Front Panelq Input selectorr Gain selector

12 dB 18 dB 24 dB
w Input display
e Function indicators
OUTPUT PHASEMONOo Power switch!0Output selector

Rear Panelt Loudness compensator selector
OFF 1 2 3uVolume level display
yFunction indicators i Volume control
RECORDER
COMPENSATORATTENUATOR

knob@0 Recorder playback/!9 Line input connectors

LINE (AD) TUNER CD
LINE 1, 2, 3

With line input signal: pin ② negative (-), pin ③ positive (+)
With balanced input signal: same phase as source equipment[Can be switched with output phase selector button !2 ]@1 Line output

connectors (2 sets)!8 Attenuator button
Sub panel

EXT PRE ALL
BAL LINE OFF@3Balanced input connectors (4 sets)
BAL (AD) CD-BAL!7 Headphone jackPressing this button
opens the sub panel!1 Display

BAL 1, 2@4 EXT PRE input connectors (2 sets) LINE/BAL!6 Headphone level selector

ON/OFF button

LOW MID HIGH
!5 Recorder output ON/OFF and PLAY buttons!2 Output phaseselector button!3 Stereo/monoselector button@5 AC power supply connector★

!4 Balance control

C-3850 Guaranteed Specifications＊Guaranteed specifications are measured according to EIA standard RS-490. ＊Gain selector set to 18 dB position● Frequency
Response

BALANCED/LINE INPUT
3 − 200,000 Hz ＋0 −3.0 dB
20 − 20,000 Hz ＋0 −0.2 dB● Total Harmonic Distortion (for all inputs) 0.005%● Input Sensitivity, Input ImpedanceSensitivity
Input impedance
For rated output For 0.5 V output
252 mV
63 mV
40 kΩ (20 kΩ/20 kΩ)
BALANCED
252 mV
63 mV
20 kΩ
LINE
Input

● Rated Output Voltage, Output Impedance
BALANCED/LINE OUTPUT 2 V 50 ohms
● S/N Ratio
Input shorted, IHF-A weighting
Input
S/N ratio at rated output
BALANCED
115 dBLINE
115 dBS/N ratio (EIA)
110 dB
110 dB● Maximum Output Level (0.005% THD, 20 − 20,000 Hz)
BALANCED/LINE OUTPUT:
7.0 V
RECORDER REC (with AD input): 6.0 V● Maximum Input BALANCED INPUT:
6.0 V
Level
LINE INPUT:
6.0 V● Minimum Load Impedance
BALANCED/LINE OUTPUT:
600 ohms
RECORDER REC:
10 kilohms● Crosstalk−90 dB or better at 10 kHz (EIA)● Gain (Gain selector: 18 dB) ＊ Gain selector allows increase or decrease by 6 dB,
except for REC output.
BALANCED INPUT→ BALANCED OUTPUT: 18 dB
BALANCED INPUT→ LINE OUTPUT:
18 dB
LINE INPUT→ BALANCED OUTPUT: 18 dB
LINE INPUT→ LINE OUTPUT:
18 dB
BALANCED/LINE INPUT → RECORDER REC:
0 dB
● Loudness Compensation
1: ＋2 dB (100 Hz), 2: ＋4 dB (100 Hz), 3: ＋6.5 dB (100 Hz)
8 ohms or above● Headphone Jack Suitable impedance:
Output Level:
2 V (40 ohms)
Gain (LOW, MID, HIGH): ±10 dB from standard MID level−20 dB● Attenuator● Power Requirements
AC120 V/220 V/230 V, 50/60 Hz (Voltage as indicated on rear panel)● Power Consumption 55 watts● Maximum Dimensions
Width 477 mm (18-3/4”)
Height 156 mm (6-1/8”)
Depth 412 mm (16-1/48”)● Mass25.0 kg (55.1 lbs) net
32.0 kg (70.6 lbs) in shipping carton

Remarks★ This product is available in versions for 120/220/230 V AC. Make sure that the voltage shown on the rear panel
matches the AC line voltage in your area.
★ The 230 V version has an Eco Mode that switches power off after 120 minutes of inactivity.
★ The shape of the AC inlet and plug of the supplied power cord depends on the voltage rating and destination country.

●@2 Balanced output connectors (2 sets)

recording connectors

Supplied accessories:

AC power cord
Audio cables with plugs ASL-10
Remote commander RC-210
Cleaning cloth

The specifications and appearance of this product are subject to change without notice.

5年間保証

F1505Y PRINTED IN JAPAN 850-2192-00（B1）