●AC vo lt age s ta bi li ze r b as ed on w av ef orm s ha pi ng te ch no lo gy ●
plies up to 510 VA of extremely clean energy
generator
●Highly effective waveform compensation ●
capability
●Superb interference rejection ●
●Low-distortion reference waveform
Outstanding current
Built-in meter for monitoring vital
Sup-
pa ra me ter s: o ut put pow er , input /o utp ut v ol tag e, i np ut/ ou tp ut di st or tio n
●Sophisticated protection features ●
Large, high-efficiency toroidal transformer
The photograph shows the 230 V version.
Solve power supply problems once and for all — Revolutionary waveform
shaping technology made even more precise, to create a pure energy
source of up to 510 VA, rated for 120 V ±1.5 V/230 V ±3 V with max. 0.1%
THD. Connect audio or video equipment for a drastic improvement in
sound and picture quality. Visually monitor the quality and efficiency of
the power source using the built-in meter with AUTO-MONITOR function.
The Clean Power Supply components from Accuphase are
the result of intensive research into every aspect of powering
demanding equipment from the AC grid. They are designed to
ensure ideal conditions without compromise. Noise and
impurities are removed from the AC power line and signal
quality is improved by continually monitoring and shaping the
power supply waveform in real time. Revolutionary high-speed
circuitry adds or subtracts exactly the required amount of
compensation, thereby minimizing distortion and creating a
perfect waveform. The result is a drastic improvement in the
sound and picture quality of audio and video equipment.
The PS-520 features a differential push-pull arrangement of
power MOS-FETs for the waveform compensation amplifier,
which further improves the precision of the reference signal
and thereby the sound quality and performance of the power
supply. Balanced transmission is used for the link to the power
section, resulting in a cleaner output waveform with minimal
distortion. The use of high-quality AC outlets meeting exacting
standards with regard to electrical safety, and impedance
matching of all outlets means greatly improved reliability. All
circuitry in the PS-520 is analog. The power source waveform
containing noise and distortion is compared to a highly
accurate and stable reference waveform. Based on this
comparison, the PS-520 then adds or subtracts exactly the
required amount of correction to create a clean power supply.
The required compensation typically is only a fraction of
overall power, which allows the PS-520 to operate with high
efficiency while producing little heat. Since there are no
oscillators or switches, the PS-520 itself does not act as a
source of spurious high-frequency noise.
AC Voltage Stabilizer Based on Waveform Shaping Technology
The PS-520 accepts AC power on the input side, processes it with
internal control circuitry, and supplies it as clean AC power on the
output side. Most
of the AC energy
from the input is
carried over to the
Efficiency
[%]
Input power
[VA]
Load: purely resistive
Efficiency
output. The introduced loss consists
only of the power
Input/output power
required for waveform compensation.
As shown in Figure
1, the signal from
the secondary winding S
1
of the transformer reaches the
adding/subtracting
circuit and appears
at the output as
output voltage
e
0
. The secondary winding S
signal from the
transformer goes
0 100 200 300 400 500
Output power/input power (efficiency) characteristics
THD
[%]
0.8
0.6
0.4
0.2
0
2
Load: purely resistive
100 200 300 400 500
Output power/THD characteristics
PS-520 Load Characteristics
Output power [VA]
Output power [VA]
to the reference
waveform generating circuit where it becomes a high-precision sine
waveform ei synchronized to the input frequency of 50/60 Hz. This
reference sine wave e
i
is then used as reference signal to be compared to the output voltage. The differential component is extracted
and used by the adding/subtracting circuit to provide exactly the
required amount of compensation for turning the output into a highprecision waveform.
Superb Interference Rejection
The input side of the PS-520 is equipped with a line
filter, an isolation transformer with shielding between
The diagram shows the 230 V AC version
Measurement circuit transformer
Waveform
after filtering
protection
Inrush current
Isolation
transformer
Hum blocker
Before waveform shaping
Input waveform with
noise and distortion
〜AC IN
Circuit
protector
Line filter
Figure 1 PS-520 Operation Block Diagram
Before waveform shaping
S1
SecondaryPrimary
S2
Meter
Large filtering
capacitors
Rectifier
Balanced
transmission
signal
generator
Reference
Reference waveform
e
i
the primary and secondary side, and a high-speed
adding and subtracting circuit. This thorough,
three-stage approach reliably removes any
high-frequency noise components present in the
power line, such as generated by digital equipment.
The output impedance of the amplifier section is
extremely low, which minimizes the risk of mutual
interference between components connected to the
outputs of the PS-520.
Built-in Meter Allows Easy Monitoring of
Output Power (VA), Input/Output Voltage (V),
Input/Output Distortion (%). Excessive Load
Indicated by Flashing LEDs.
T
he constantly fluctuating voltage and distortion at a
regular household AC outlet can be monitored in real time.
Assembly with input voltage/distortion monitoring circuitry
The meter also lets the user see at a glance how much
power (VA) the connected equipment is consuming at any
given time, which is especially helpful for components
such as power amplifiers whose power consumption
differs considerably depending on the actual volume.
An AUTO-MONITOR function that automatically switches
the meter indication is also provided.
Power Supply Waveform and Clean PS-520 Output Waveform
Almost all electrical devices used in a household convert the AC supplied by the
outlet into a DC current for powering internal circuits. This task is performed by a
rectifier consisting of a combination of diodes and capacitors. The rectifier load
current has a pulse characteristic with a large current flowing momentarily in the
vicinity of the peak of the voltage waveform (sine waveform). The resistance of
electrical in-wall wiring and power cords affects the waveform and leads to a drop in
voltage, which is seen as clipped waveform with higher amounts of distortion. The
clipped waveform results in less power being available, so that connected equipment
does not receive enough energy to develop its full potential. The distorted waveform
also contains many unwanted frequency components, or harmonics. When entering
the audio circuitry of an amplifier through the power supply, such harmonic
components can interfere with the audio signal and cause intermodulation distortion
which has a highly detrimental effect on sound quality. The AC power therefore not
only is subject to noise and distortion while being delivered to the load, it is then
further degraded in the equipment itself through the process of power consumption.
When passing through the PS-520, practically all unwanted harmonics components
in the audible range are removed (see frequency spectrum in the graph below), and
the waveform is restored to its original sine wave pattern as shown in photograph (c).
−
−
〔dB〕
−
−
−
−
100.0
120.0
AC Line Power Spectrum 1
0.0
50Hz
20.0
40.0
60.0
80.0
0 10k 20k
Frequency spectrum of power line (photo b)
Frequency spectrum of power line
〔dB〕
PS-520 Output Power Spectrum 1
0.0
50Hz
−
20.0
−
40.0
−
60.0
−
80.0
−
100.0
−
120.0
〔Hz〕
0 10k 20k
Frequency spectrum of PS-520 output (photo c)
Protection
circuit
DC/AC detection
Temperature detection
Adding/
subtracting
circuit
Waveform
comparator
〔Hz〕
Function buttons and LED indicators
Meter switching circuit
Measurement circuit
Output waveform
e
o
OUTPUTS
Current detection
Error
detector
Reference waveform
Waveform
differential component
compensation amplifier
Meter scale of 230 V AC version
Waveform control circuit
Photo (a) Current waveform of rectified load
Photo (b) Voltage waveform of AC line
(distortion approx. 3%)
Photo(c)PS-520outputwaveform
(distortionapprox.0.06%)
The photograph shows
the 230 V version.
Clean internal
▲
layout designed
for optimal
power and
signal flow
Distortion scale
(%)
Volt-Ampere scale
(VA)
Voltage scale (V)
Outstanding Current Capability
The power amplifier which performs addition/subtraction for waveform compensation uses the
pure complementary push-pull differential principle for high gain, excellent precision, and
complete operation stability. In the output stage, a 10-parallel complementary arrangement (10
P channel pairs, 10 N channel pairs) of power MOS-FETs rated for max. 30 A is used. This
reduces the load of the preceding stage and reliably absorbs even rapid load fluctuations,
providing a rated output current of 2.2 A (4.2 A), with an instantaneous peak current (inrush
current) rating of 30 A (60 A). This demonstrates the excellent current capability of the PS-520.
Compensation Amplifier Based on High-Precision Reference Signal Creates Pure 230 V (or 120 V) AC Source
■Low-Distortion Reference Signal Generator
In the PS-520, the power supply output frequency is matched to the input frequency
without the use of an oscillator that can become a source of noise and interference.
The zero-cross point of the signal at the S
1) is detected and used as AC voltage sine wave reference to generate a highly
accurate square waveform. A newly developed 50/60 Hz band-pass filter and
band-stop filter is then applied to
the waveform. The filter frequency
is switched in sync with the input
frequency, for automatic 50 Hz and
60 Hz support. By routing the signal
through another band-pass filter, a
low-distortion sine wave (reference
signal) is created that is not
dependent on the input voltage.
Power supply
input waveform
From secondary
winding of power
transformer
Square wave
〔50Hz〕
Band-pass
Square wave
generator
Band-pass
〔60Hz〕
Reference Signal Generator Block Diagram
2 winding of the power transformer (see Fig.
Assembly with reference signal generator and other circuitry
Reference sine
waveform
filter
filter
Band-stop
filter
Band-stop
filter
Band-pass
filter
Reference output
waveform
■Superior Waveform Compensating Power
The waveform compensation capability of the PS-520 not only eliminates noise and distortion, it
also deals with sudden and rapid voltage fluctuations in real time. When the input voltage is
110/220 V, the voltage at the secondary side of the transformer will also be 110/220 V. To bring
this to 120/230 V, 10 volts
must be added, as shown
in Figure (a). Conversely,
if the input is 130/240 V,
10 volts must be subtracted to yield 120/230 V.
(As the figures show, in
actual operation, the peak
voltage of 120/230 V is
170/325 V, and the peak
value of 10 V, namely
14.1 V, is added or subtracted.) The sine wave
(e
i
) synchronized to the
input frequency and the
output voltage (e
compared, and for any
excessive or missing
component, a compensation waveform up to a
maximum of ±10 V (peak
value ±14.1 V) is generated and imposed on the output voltage. Consequently, for an input voltage range of 108 V - 132 V/207 V - 253 V at the rated load of 510 VA , the output voltage is kept
constant at 120 V ±1.5 V/230 V ±3 V, with a maximum distortion ratio of 0.1% . These values
demonstrate the outstanding waveform compensation ability of the PS-520.
0
) are
PS-520 120/230 V AC
output waveform
＋
170V/
325V
0
−
170V/
325V
＋
14.1V
0
−
14.1V
(a)
If power source voltage is lower than
120 V/230 V, addition is performed
110/220 V AC
input waveform
Compensation
waveform
14.1 V
14.1V
＋
t
−
＋
t
−
Wave form Shapin g Princ iple of PS- 520
▲
Assembly with 10 parallel
push-pull power MOS-FETs
mounted to large heat sink,
waveform compensation amplifier
for addition/subtraction, etc.
170V/
325V
170V/
325V
14.1V
14.1V
(b)
14.1V
130/240 V AC input
waveform
PS-520
110/220 V AC
output waveform
0
Compensation
waveform
0
If power source voltage is higher than
120 V/230 V, subtraction is performed
t
14.1V
t
Sophisticated Protection Features
Strong Power Supply With Massive High-Efficiency Toroidal Transformer and Large Filtering Capacitors
All operation factors including voltage, current, power, DC
components, temperature etc. are constantly monitored, for
reliable protection in case of any problem.
z
When the combined
load of connected
equipment exceeds the
maximum rated output
power of 510 VA, the
indicator LEDs of the
meter selector buttons
flash as a warning
indication.
x
When input current
overload occurs, the
Assembly with protection circuitry
circuit protector shuts off the power. Reduce the connected load and
turn power on again.
The power transformer, a crucial component, is a
massive toroidal type. Toroidal power transform ers
employ large-gauge copper wiring on a donut-shaped
core, which creates a smooth and closed magnetic
path with minimal exte rnal leakage. The r esult is
extremely low impedance and high efficiency. Two
specially design ed high -quality 22,000 μF filtering
capacitors selected for outstand ing sound provide
ample smoothing capacity.
High-Performance Parts Selected for Sound Quality
The six (for 230 V) or eight (for 120 V) AC outlets of the PS-520 are high-quality types. Internal
circuitry makes ample use of gold-plated parts and customized parts. The circuit protectors are
quality devices that react with higher speed than conventional circuit breakers. Vibration-damping
rubber parts are used for mounting. This attention to detail is evident throughout the PS-520.
c In case of momentary power overload such as caused by
inrush current when a component is switched on or when a
power amplifier reproduces a peak passage in the music, a
30/60 A current limiter becomes active to ensure safe use.
v Internal operation is monitored constantly. When a problem
such as DC voltage in the output or output voltage exceeding
the maximum rating is detected, the output is switched off
instantly to protect connected components.
b When the temperature of the internal heat sink or power
transformer is very high for an extended period, the circuitry is
automatically shut down.
Meter of 120 V AC version
■Front panel
(The photograph shows the 230 V version.)
q
★
Line filter, vibration-damping rubber, circuit protector
PS-520 Meter (Power) Indication and Load
The power consumption of electrical equipment, as indicated on the equipment itself and in catalogs
and other documentation according to legal requirements, is usually given in watts (W). This figure
Parts selected for high sound quality and high reliability
represents the so-called effective power. However, the actual power drawn by the equipment is
larger than the effective power. This is called the apparent power which is calculated by multiplying
the applied voltage (230 V or 120 V) with the actual current. The unit for apparent power is VA
(Volt-Ampere). Since the value shown by the meter of the PS-520 is the apparent power, the
reading will be higher than the power consumption (W) given in catalogs and specification sheets.
●
The rated power limit of the PS-520 is 510 VA. When deciding on equipment to be
connected, select components so that the total remains within this limit, and check
actual power consumption using the meter.
●
High-output class-A power amplifiers, such as the A-65, which constantly draw a high
idling current when switched on cannot be connected to the PS-520.
●
In case of overload, the indicator LEDs of the meter operation selector buttons flash. Reduce the load by
reducing the number of connected components until the indicator LEDs stop flashing and stay constantly lit.
●
w
Output connectors of 120 V AC version
■Rear panel
(The photograph shows the 230 V version.)
q Met er
(Output power, input/output voltage, input/output distortion)
w Pow er s wi tch/Cir cu it p rotecto r
e Meter operation selector buttons
VOLT-AMPERE (VA) VOLTAGE INPUT/OUTPUT (V)
DISTORTION INPUT/OUTPUT (%) AUTO-MONITOR
Remark
The 230 V AC and 120 V AC versions of the PS-520 differ regarding meter voltage indication, AC output connector shape, supplied power cord, etc. Make sure that you have the correct
★
＊The PS-520 is available in 230 V AC and 120 V AC versions. The actual allowable voltage is indicated next to the AC power connectors on the rear panel. Be sure to check this
indication before using the PS-520.
＊This product can be used only on a regular household AC circuit rated for 230 V or 120 V AC, 50/60 Hz. Using the product with portable AC generators, airplane or ship power
generators or other types of power sources is not possible.
＊
This product is designed to improve the quality of AC power supplied to audio or video components. Do not use it to power industrial type equipment or common household electrical
Caution
appliances.
＊Do not use this unit for powering equipment where failure incurs a risk of injury or fatal accidents (medical equipment, aviation equipment, traffic control equipment, furnace and heating
control equipment, safety devices, etc.). Accuphase will not be liable for any problem occurring due to use of the PS-520 with the above type of equipment.
★
r
Theusable power supply
voltage is indicated here.
★
e
★
t
r Output connectors
(AC outlets)
t AC power connector
★
★
The power consumption of integrated amplifiers and power amplifiers varies considerably depending on the
actual audio output. After connecting such equipment, perform playback and verify that the meter indication
does not exceed 510 VA also at the highest volume level setting.
Rated output capacity
Rated output voltage
Rated output current
Output frequency
Instantaneous peak current capacity
Output waveform THD
Rated input voltage
Input frequency
No-load power consumption
Cooling principle
Meter
VOLT-AMPERE
VOLTAGE INPUT/OUTPUT
(green zone of scale)
DISTORTION INPUT/OUTPUT
AUTO MONITOR
Maximum Dimensions
Mass
PS-520 GUARANTEED SPECIFICATIONS
120 V version 230 V version
510 VA (continuous)
120 V AC±1.5 V 230 V AC ±3.0 V
4.2 A 2.2 A
50 Hz or 60 Hz (identical to input frequency)
60 A 30 A
0.1% or less
120 V AC 230 V AC
50 Hz or 60 Hz
50 W
Natural air cooling
*
In case of overload, the indicator LEDs of the meter selector buttons flash.
0-510 VA
120 V AC ±5% 230 V AC ±5%
0-6%
Cycles through VOLT-AMPERE -- DISTORTION
DISTORTION OUTPUT indicationin 4-second intervals
Width 465 mm (18-5/16")
Height 181 mm (7-1/8")
Depth 386 mm (15-3/16")
24.1 kg (53.1 lbs.) net
30.0 kg (66.1 lbs.) in shipping carton 30.0 kg (66.1 lbs.) in shipping carton
Supplied accessories: • AC power cord 2 m
Filtering capacitors
23.5 kg (51.8 lbs.) net
version.
• Specifications and design subject to change without notice for improvements.
http://www.accuphase.com/
D1205Y PRINTED IN JAPAN 851-0213-00 (B1)
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