m AC voltage stabilizer based on waveform shaping technology m Superior
waveform compensating power m Excellent current capability m Highly
effective interference rejection m Built-in meter allows monitoring of output
power, input/output voltage, and input/output distortion m Elaborate
protection features m Large "Super Ring" toroidal transfor merTap into a totally clean source of AC energy, free from distortion and highfrequency noise. Revolutionary waveform shaping technology enables highly
precise compensation, providing a pure energy source with 120 V AC ± 2%
(or 230 V AC ± 2%). Audio or video equipment with a total power consumptionof up to 510 VA can be connected, for a drastic improvement in sound andpicture quality. Monitoring of output power, input/output voltage, and input/
output distortion is possible.
The PS-500V is a revolutionary product whichremoves the noise components from the AC powerline and improves signal quality by continuallymonitoring and shaping the power supply waveform.
As a result, sound and picture quality of audio andvideo equipment is drastically improved.
The AC power lines in ordinary homes as well as inoffice buildings or recording studios invariably sufferfrom high amounts of noise and waveform distortion.
The ideal waveform of the power supply is sinusoidal,
but when various electrical devices are connected tothe same power source, unwanted voltage fluctuations
will occur. In addition, appliances containing digital
circuits, such as computers or telephones, emit highfrequency noise components that can enter audio orvideo components via the power supply and severely
affect sound or picture quality by causing
intermodulation noise and distortion. Only when suchnoise interference is removed and totally clean poweris supplied are audio and video components able todevelop their full potential. This is especially true forhigh-end equipment. Consequently, upgrading thequality of the AC power source is bound to result in a
drastic improvement in the overall performance of youraudio/video system.
The PS-500V constantly monitors the input voltage
waveform and adds or subtracts exactly the required
amount of compensation to achieve a perfectly
regular, sinusoidal waveform. The compensation
required by this innovative technique typically is only
a fraction of overall power. The PS-500V therefore
operates with high efficiency and produces little heat,allowing it to be designed as a fairly compact andlightweight unit. Because the output impedance of its
AC outlets is extremely low, any combination ofcomponents with a total power consumption of 510
VA maximum can be connected. Since it contains nooscillators or switching circuitry, the PS-500V itself
does not act as a source of spurious high-frequency
noise.
AC Voltage Stabilizer Based on Waveform Shaping
TechnologyThe PS-500V accepts AC power on the input side,

Power supply waveform and PS-500V output waveform
Almost every electrical device used in an household converts theAC supplied by the outlet into DC current for powering its internal
circuits. This task is performed by a rectifier. As shown in photograph, the rectifier load current has a pulse waveform with a large
current flowing momentarily in the vicinity of the voltage peak.
This causes a voltage drop, resulting in clipping of the voltage
waveform, as shown in photograph . A clipped waveform with ahigh amount of distortion 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.

Photoload

Current waveform of rectified

Photo

Voltage waveform of AC line
(distortion approx. 3%)

When passing through the PS-500V, the deformed waveform
is restored to its original sine wave pattern, as shown in.
photographFrequency spectrum of power line(photo )Frequency spectrum of PS-500V
output (photo )Frequency spectrum of power line

processes it using internal control circuitry, andsupplies it as clean AC power on the output side. Mostof the AC energy from the input is carried over to theoutput. The loss introduced by the PS-500V is verysmall, since it consists only of the power required forwaveform compensation. Compared to conventional
AC voltage stabilizers, efficiency is much higher andexcess thermal energy is low, allowing the unit to bemade relatively small and lightweight. Since the power
supply frequency is synchronized to the input, aninternal oscillator is not required. Therefore the unit

Photo
PS-500V output waveform(distortion approx. 0.2%)

itself does not
generate any
high-frequency
noise.
Figure 1 shows a
block diagram ofthe unit. The
signal from thesecondary
winding S1 of thetransfor mer
reachestheadding/subtracting circuit
and appears at
the output as
output voltage(e0). A part of theoutput voltage isrouted to the –input of thew a v e f o r mcomparator for
w a v e f o r mcomparison. TheS2 signal fromthe transformer goes to the reference waveformgenerating circuit where it becomes the high-precisionsine waveform (ei) synchronized to the input frequencyof 50/60 Hz. This sine wave signal is then routed tothe + input of the waveform comparator to be usedas the reference signal. By comparing the two input
signals, a differential component is extracted. Basedon this information, the adding/subtracting circuit can
provide exactly the required amount of compensation
for turning the output into a high-precision sinewaveform.

Superior Waveform Compensating Power
When the input voltage is 110 V (220 V), the voltage
at the secondary side of the transformer will also be
110 V (220 V). To bring this to 120 V (230 V), 10 volts
must be added, as shown in Figure 3 (a). Conversely,

removing any high-frequency noise components
present in the power line, such as generated by digitalequipment. The primary and secondary windings ofthe power transformer are kept totally separate, andthe fully shielded design shuts out any externallyinduced noise.
Since the PS-500V uses the AC feedback principle,
output impedance is extremely low. This prevents any
possibility of mutual interference between components
connected to the outputs of the PS-500V.
Built-in Meter Allows Monitoring of Output Power,Input/Output Voltage, Input/Output Distortion.
Overload Is Indicated by Flashing Meter Illumination.
The meter of the PS-500V lets the user see at a glance
how much power (VA) the connected equipment isconsuming at any given time. This is especially helpful
for components such as integrated amplifiers or power
amplifiers whose power consumption differs
considerably depending on the volume setting andactual music signal. The maximum output power ratingof the unit is 510 VA. When this is exceeded, the meter
illumination flashes as a warning indication.

if the input is 130 V (240 V), 10 volts must besubtracted to yield 120 V (230 V), as shown in Figure
3 (b). In actual operation, the peak value of 10 V,
namely 14.1 V is added or subtracted.
Comparing a precise sine wave synchronized to theinput frequency with the output voltage yields acompensation waveform which is imposed on theoutput voltage. Consequently, for an input voltage
range of 108-132 V AC (200-253 V AC) and a constantload of 510 W, the output voltage is kept constant at
120 V ±2% (230 V ±2%), with a maximum distortion
ratio of 0.3%. These values demonstrate theoutstanding waveform compensation ability of thePS-500V.
Note: The above explanation is for the 120 V AC
version of the PS-500V. Figures in brackets refer tothe 230 V AC version.
Highly Effective Interference Rejection
The input side of the PS-500V isequipped with a line
filter for

Excellent Current Capability
The power amplifier which performs waveformcompensation is configured as a pure complementary
symmetrical circuit using current feedback forunsurpassed
operation stability.
The output stage
uses transistors
ratedforamaximum currentof 10 amperes.
These devices areconnected in a10-parallel
Assembly with input voltage/complementary
distortion monitoring circuitry
push-pull arrangement, which boasts excellent current capability.
Elaborate Protection Features Assure Total
Operation Safety
When a problem occurs during operation, the circuit
breaker integrated in
the power switch
immediately shuts
off the power, toprotect the unit andanyconnectedcomponents.
Assembly with protection
circuitryn Assembly with output stage with 10parallel push-pull multi-emitter devices
mounted to large heat sink, waveformcompensation amplifier for addition/subtraction, comparator for reference
waveform and output waveform,deviation detector, etc.

= If an input current overload occurs, such as when
the output is short-circuited, the power is shut off.
> In case of momentary power overload, such as
caused by inrush current when a component isswitched on or when a power amplifier reproducesa peak passage in the music, a current limitergoes into action. For the 120 V version, themaximum current is 60 A and for the 230 V version
it is 30 A.
? When DC voltage is detected in the output or when
the output voltage exceeds the maximum rating,the output is switched off to protect connectedcomponents.
@ When the temperature of the internal heat sink or
power transformer exceeds 110ºC, the circuitry
is automatically switched off.

The power transformer plays a vital role in any power
supply. The PS-500V uses a large toroidal type rated

Multiple Output Connectors
CoilCore

Coil

The PS-500V can supply a number of components
such as a CD player, DAT recorder, preamplifier, power
amplifier or other audio or video components, provided
the combined power consumption is less than 510
VA.
Conventional toroidaltransformer"Super Ring" type toroidaltransformer of PS-500V

Fig. 4 Cross section of toroidal transformer core

PS-500V Guaranteed Specifications

Power Meter Indication and Load
The power consumption of electrical equipment, as indicated on the equipment itself
and in catalogs and other documentation, is usually given in watts (W). This figure
represents the so-called effective power which is stated according to legal requirements.
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
with the actual current. The unit for apparent power is VA (volt-ampere).
Since the value shown by the power meter of the PS-500V in the "VOLT-AMPERE"
position is the apparent power, the reading will be higher than the power consumption(W) given in catalogs and specification sheets.
mmmm

The rated power limit of the PS-500V is 510 VA. Whendeciding on equipment to be connected, power
consumption figures given in catalogs and the like can beused for a general estimate, but actual power consumption
should be checked using the meter.
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 power consumption does notexceed 510 VA when peaks in the music are reproduced athigh volume levels.
In case of overload, the meter illumination flashes. Reduce
the load by reducing the number of connected components
until the illumination stops flashing and stays constantly lit.
For reference, some Accuphase products are listed shownbelow.

for 750 VA. Toroidal power transformers have largegauge copper wiring on a donut-shaped core, resulting
in very low impedance, high efficiency, and compact
dimensions.

Strong Power Supply With Large "Super Ring"
Toroidal Transformer and High Filtering Capacity

120 V version
Rated output capacity
Rated output voltage

120 V AC ±2.4 V

230 V AC ±4.6 V

Rated output current

4.2 A

2.2 AOutput frequency

50 Hz or 60 Hz (identical to input frequency)

Instantaneous peak current capacity

60 A

30 A

Output waveform THD

0.3% or less

Rated input voltage

120 V AC

Input frequency
Can be connected:
Preamplifiers, CD players, tuners
and other low-power components
E-407, E-306V, E-211, A-20V

230 V version

510 VA (continuous)

230 V AC
50 Hz or 60 Hz

No-load power consumption

55 W

Cooling principle

Natural air cooling

Meter.........................................................................................................................................................................
0 – 510 VA

Can be connected at normal
volume settings (*):
P-1000, P-700, P-550, P-450

VOLT-AMPERE
The meter illumination flashes when an overload occurs.........................................................................................................................................................................

Cannot be connected
A-50, A-50V.........................................................................................................................................................................

(*) When driving loudspeakers with an
impedance of about 8 ohms to normal
listening levels

Dimensions

475 mm (18-11/16”) width,
180 mm (7-1/16”) height,
394 mm (15-1/2”) depth

Weight23.8 kg (52.5 lbs.) net
27.0 kg (59.5 lbs.) in shipping carton

VOLTAGE INPUT/OUTPUT(green zone of scale)

120 V AC ±5%

DISTORTION INPUT/OUTPUTn REAR PANELn FRONT PANEL

Output connectors of
120 V AC version
Meter of 120 VAC version)R

The usable power supplyvoltages are indicated.

(The photograph shows the 230 V AC version.)*0,0+) Power switch/circuit protector* Meter (Output power, input/output voltage, input/output distortion)0+ Meter operation selector
VOLT-AMPERE
VOLTAGE INPUT/OUTPUT DISTORTION INPUT/OUTPUT

Caution230 V AC ±5%
0 – 6%-00, Output connectors (AC outlets)- Power connector (for supplied power cord)0Remark
0 The 120 V AC and 230 V AC versions of the PS-500V differ regarding meter voltage indication,AC output connector shape, supplied power cord, etc. Make sure that you have the correct version.

✻ The PS-500V is available in a 120 V AC and 230 V AC version. The actual allowable voltage is indicated besides the AC power
connectors on the rear panel. Be sure to check this indication before using the PS-500V.
✻ This product can be used only on a regular household AC circuit rated for 120 V or 230 V AC. Using the product with portable ACgenerators, 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 appliances.

❇ Specifications and design subject to change without notice for improvements.

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