Accuphase E-407 User manual

INTEGRATED STEREO AMPLIFIER
E-407
mTriple parallel push-pull output stage delivers quality power: 180 watts × 2 into 8
ohms mCurrentfeedbackprinciplecombinessuperbsoundwithtotaloperationstability
m Logic-controlled relays for shortest signal paths m Separator switch allows
independent useofpre/power sections m Large toroidalpowertransformerm Balanced
inputs m Option board available for playback of analog records

State-of-the-artintegrated amplifierfeaturescurrentfeedbacktopology
for superb high-range phase fidelity. Wide-range power transistors in
tripleparallelpush-pullconfiguration and massivetoroidaltransformer
deliver ample power: 260 watts × 2 into 4 ohms, 180 watts × 2 into 8
ohms. Option board enables analog record reproduction in top-notch
quality.
The E-407 represents a new pinnacle of ampli-
fier design. Featuring latest technology and us-
ing only the highest quality materials, this inte-
grated stereo amplifier is destined to become a
new reference. Frequency response, S/N ratio,
and all other performance aspects make the
E-407 perfectly suited for the new generation
of ultra high quality program sources such as
SACD and DVD-Audio.
An integrated amplifier provides various advan-
tages such as convenient operation and modest
space requirements.However, because its over-
all gain is very high, even the slightest interfer-
ence or crosstalk at the input can have a consid-
erable effect on the sonic result.To preclude this
possibility, the E-407 is designed to achieve total
electrical and structural separation of the
preamplifier and power amplifier sections.These
two parts operate as if they were entirely sepa-
rate components.A switch even allows using the
preamplifier and power amplifier independently.
Accuphase's highly acclaimed current feedback
topology virtually eliminates phase shifts in the
upper frequency range and assures outstanding
performance and sound quality.The power am-
plifieroutput stageemploys atripleparallelpush-
pullconfiguration,using multi-emitter powertran-
sistors designed for high-power audio applica-
tions. Ample muscle is provided by the power
supply section which features a massive, highly
efficient toroidal power transformer housed in a
diecast enclosure equipped with heat fins.
In the standard configuration, the E-407 has six
inputs, two of which employ the balanced princi-
ple that assures ideal signal transmission char-
acteristics.Provisions fortwotape recorders,with
easydubbingin bothdirections,tone controls,and
loudnesscompensation are furtherattractivefea-
tures.An optional analog disc input board allows
reproduction of analog records with outstanding
sonic quality.
The external design of the E-407 continues the
Accuphasetradition,featuring achampagne gold
brushed front panel. Two large power meters in
the center are flanked by the input selector sec-
tion and the volume control.Not only by virtue of
its excellent sound, from its looks as well the
E-407 is a great addition to any living room.
Triple parallel push-pull output stage delivers
quality power:260 watts/channel into 4 ohms,
220 watts/channel into 6 ohms or 180 watts/
channel into 8 ohms
The output devices are multi-emitter power tran-
sistors designed for high-power audio applica-
tions.Thesedeviceshave excellent frequency re-
sponse, forward-current transferratiolinearity,and
switching performance characteristics.They are
connected in a triple parallel configuration (Fig-
ure 1) for low impedance and mounted directly
on a large heat
sink to assure ef-
ficient dissipation
ofthermal energy.
This allows the E-
407todeliveram-
ple power output,
amounting to 260
wattsinto 4 ohms,
220 watts into 6 ohms, or 180 watts into 8 ohms
per channel.
Current feedback topology in power amplifier
and preamplifier sections guarantees top-
level performance
In the E-407, the signal current rather than the
voltage is used for feedback.Figure 2 shows the
operating principle of this circuit. At the sensing
point of the feedback loop, the impedance is kept
low and current detection is performed. An im-
pedance-converting amplifier then converts the
current into a voltage to be used as the feedback
signal.Since the impedance at the current feed-
back point (current adder in Figure 2) is very low,
thereis almost no phase shift. Phasecompensa-
tion can be kept to a minimum, resulting in excel-
lent transient
response and
superb sonic
transparency.
Figure3 shows
frequency re-
sponse for dif-
ferentgainset-
tingsofthecur-
rent feedback
amplifier.The graphs demonstrate that response
remains uniform over a wide range.
Discrete-type line amplifier for superior sonic
purity
The line amplifier is entirely built from discrete
parts, to assure optimum performance. Using a
principle developed by Accuphase, a differential
purecomplementarypush-pull circuitis combined
with a single-ended push-pull emitter follower
outputstage.Thiscomparativelysimple topology
reduces the need for phase compensation, re-
sulting in effortless, utterly natural and transpar-
ent sound.
Highly reliable logic-controlled relays
Program source switching is performed by logic-
controlled relays which are arranged so as to
permit the
shortestpossi-
ble signal
paths. The
hermetically
sealed relays
are high-qual-
itytypes devel-
oped specifi-
cally for de-
manding com-
municationap-
plications.The contacts are twin crossbar types
plated with gold for minimum contact resistance
and outstanding long-term reliability.
Tone controls use summing active filters for
pure sound
The tone control circuitry in the E-407 was spe-
cially designed with summing active filters. Fig-
ure 4 illustrates the operation principle of this cir-
High-current power transistors
Relays connected directly to
gold-plated input/output jacks
Figure 2 Principle of current feedback amplifier
Figure 1 Circuit diagram of power amplifier section (one channel)
Figure 3 Frequencyresponse with current feedback
(Responseremains uniformalsowhengainchanges)
Line amplifier assembly with
current feedback circuitry
Bias
stabilizer

cuit. The flat signal is passed
straight through, and only when
an adjustment is required, the
characteris-
tics created
at F1 and F2
are added to
the signal,
thereby pro-
ducing the
desired
change. This
design pro-
videsefficient
control with-
out degrading signal purity.
Large toroidal power transformer and high fil-
tering capacity
The power supply section is a critical aspect of
any power amplifier.The E-407 features a large
toroidal power transformer with a rating of 600
VA.The transformer is housed in a non-resonant
aluminum enclosure filled with damping material
that has excellent heat transfer characteristics.
Toroidal transformers which use heavy-gauge
copper wiring on a ring-shaped core have vari-
ous advantages, such as very low impedance,
small size, and high conversion efficiency. The
toroidal type transformer used by Accuphase is
ideallysuited foraudio applications.Ithas the fol-
lowing characteristics:
aNear-circular core caliber allows near-circular
coil windings with high packing density, result-
ingin lowleakage fluxand minimumvibrations.
bSmaller ferrite core diameter and copper
windings with high specific gravity mean low
ferrite losses and low inrush current.
Two massive electrolytic capacitors, each rated
for 33,000 uF assure ample reserves also for re-
production of the most demanding passages.
Dedicatedheadphone amplifier for best sound
The E-407 provides a separate
amplifier for the phone jack de-
signedto providesuperior sonic
performance.The speakerout-
put can be cut off by a switch,
and the main volume control
can be used to adjust the
headphone listening level.
Two sets of heavy-duty
speaker terminals
The oversize speaker
terminals are made of
extruded high-purity
brass material which
acceptalso heavy-gaugespeakercable.Two sets
of outputs with a
speaker selector
are provided, and
bi-wiring (supply-
ing the same sig-
nal via dual leads
to speakers with
separatehigh-fre-
quency and low-
frequency inputs)
is also possible.
Large analog peak power meters
The power meters use logarithmic compression
to cover a wide dynamic range, letting you easily
monitor the output level of the rapidly fluctuating
music signal.Meter illumination can be switched
off, which is conven-
ient for example in
a home theater
setup.
nSuppliedremotecommander RC-20
Allows volume control and source
switching
Power amplifier
assembly with tri-
ple parallel push-
pulloutput devices
mounted to large
heat sink and cur-
rent feedback am-
plifier circuitry
Heavy-duty speaker terminals
Figure 4 Tone control circuit principle
(Summing active filter type)
Massive filtering capacitors and
large toroidal power transformer

GUARANTEED SPECIFICATIONS
[Guaranteed specifications are measured according to EIA standard RS-490.]
mContinuous Average Output Power (both channels driven, 20 - 20,000 Hz)
260 watts per channel into 4 ohms
220 watts per channel into 6 ohms
180 watts per channel into 8 ohms
mTotal Harmonic Distortion (both channels driven, 20 - 20,000 Hz)
0.02%, with 4 to 16 ohms load
mIntermodulation Distortion 0.01%
mFrequency Response HIGH LEVEL INPUT/MAIN INPUT
20 - 20,000 Hz +0, -0.2 dB (for rated output)
2 - 150,000 Hz +0, -3.0 dB (for 1 watt output)
mDamping Factor 120 (with 8-ohm load, 50 Hz)
mInput Sensitivity, Input Impedance
Sensitivity
For rated output For 1 W output (EIA)
HIGH LEVEL INPUT 158 mV 11.2 mV 20 kW
BALANCED INPUT 158 mV 11.2 mV 40 kW
MAIN INPUT 1.58 V 112 mV 20 kW
mOutputVoltage, Output Impedance PRE OUTPUT: 1.58 V, 50 ohms
(at rated continuous average output)
mGain MAIN INPUT ➞OUTPUT: 28 dB
HIGH LEVEL INPUT➞PRE OUTPUT: 20 dB
mTone Controls Turnover frequency and adjustment range
BASS:300 Hz ±10 dB (50 Hz)
TREBLE: 3 kHz ±10 dB (20 kHz)
mLoudness Compensation +6 dB (100 Hz), (Volume control setting -30 dB)
mSignal-to-Noise Ratio (input-converted noise)
Input shorted, IHF-A weighting
S/N ratio at rated input
HIGH LEVEL INPUT 113 dB 82 dB
BALANCED INPUT 92 dB 82 dB
MAIN INPUT 128 dB 103 dB
mPower Level Meters S/Nratio(EIA)Logarithmic compression,peakreading
meters
dB scale
mLoad Impedance 4 - 16 ohms
mStereo Headphones Suitable impedance:4 - 100 ohms
mPower Requirements 120 V / 230V (voltage indicated on rear panel)
AC, 50/60 Hz
mPower Consumption 55 watts idle
410 watts in accordance with IEC-65
mMaximum Dimensions Width 475 mm (19-11/16”)
Height 180 mm (7-1/16”)
Depth 423 mm (16-5/8”)
mWeight 23.7 kg (52.2 lbs) net
28.0 kg (61.7 lbs) in shipping carton
mSupplied Remote Commander RC-20 Remote control principle: Infrared pulse
Power supply: 3 V DC (IEC R6 batteries × 2)
Dimensions:55(width) ×194(height) × 18(depth)mm
Weight: 100 g (including batteries)
1Inputselector
LINE-BAL LINE-2 LINE-1 CD
CD-BAL TUNER OPTION-1 OPTION-2
2Left/right output meters (dB scale)
3Volumecontrol
4Power switch
5Meteroperation/illumination switch
6Speakerselector
OFF A B A+B
7Tape copy selector 1➞2 OFF 2➞1
8Recordingoutput/tape monitor selector
REC OFF SOURCE TAPE-1 TAPE-2
9Mode switch
FTone control ON/OFF switch
GBass control
HTreblecontrol
IBalance control
JHeadphonejack
KLoudnesscompensator switch
LAttenuatorswitch
MLine inputs
NTape recorder inputs and outputs
OLeft/rightspeaker output terminals
PCD/LINE balanced inputs
Q
Preamplifier/poweramplifierseparatorswitch
RPreamplifieroutputs
SPower amplifier inputs
TAC inlet (for supplied power cord)H
USwitched AC outletsH
Input impedance
Input
S/N ratio (EIA)Input
Option Boards
The rear panel of the E-407 provides two slots in which an optional input board can be installed easily.
Two types of boards, as shown below, are available.
mAnalog Disc Input Board AD-9 and Line Input Board LINE-9 can also be used.
mBoth boards use the AAB (Accuphase Analog Bus) interface.
Line Inputs Board LINE-10
This option board provides an additional set of
conventional line inputs which can be used to
connectaCD player,tuner,orothercomponent
with analog output.
Analog Disc Input Board AD-10
This board contains a high-performance, high
gain phone equalizer.The board can be used
with any type of phone cartridge.
Internal DIP switches control MM/MC operation, MC input
impedance, and subsonic filter on/off.
Gain : 36 dB
Input impedance : 47 kohms
Gain : 62 dB
Input impedance : 10/30/100 ohms
(selectable)
MM
MC
Remarks
H This product is available in versions for 120/230 V AC.Make sure that the voltage shown on the rear panel matches the AC linevoltage in your area.
H The 230 V AC model does not have the SWITCHED power outlet.
H The shape of the AC inlet, plug of the supplied power cord, and AC outlet depends on the voltage rating and destination country.
H These switched AC outlets may not be supplied depending on the safety standards or regulations applicable in the particular country to where the unit is destined.
Supplied accessories: • AC power cord
• Remote commander RC-20
PRINTED IN JAPAN A9910 851-0162-00 (AD1)
Versatile input configuration including bal-
anced connectors
The input selector of the E-407 controls a total of
eight positions (including two option board posi-
tions) plus
two tape re-
corders. Two
of the stand-
ard inputs
(CD and
LINE)are de-
signed for
balanced connections which are not affected by
externally induced noise, ensuring signal trans-
mission with optimum sonic purity.
High-quality volume control,supplied remote
commander allows source switching and vol-
ume adjustment
Separator switch and set of inputs/outputs en-
able independent use of preamplifier and
power amplifier sections
mSpecifications and design subject to change without notice for improvements.
Balanced input connectors
nREAR PANEL
nFRONT PANEL
P
123
45 6789F
GH IJ KL
Option Board
Slots
MN O
QRS TU
HH