Hafler P505 Installation And Operation Manual

THE

Hafler P505 Professional Power Amp

ha fler

P505

PROFESSIONAL

POWER AMPLIFIER

INSTALLATION AND OPERATION

5910 Crescent Boulevard, Pennsauken, New Jersey 08109

CAUTION:

IF THE SPEAKER FUSES BLOW,

SOME DISTORTED SOUND CAN BE

HEARD. THEREFORE IF AMPLIFIER
MALFUNCTIONS, ALWAYS CHECK
FOR BLOWN FUSES FIRST.

LM135

THE DAVID HAFLER COMPANY

SPECIFICATIONS

Power Rating: 400 watts per channel into 4 ohms at less than 0.04% THD from 20 Hz to

20 kHz with both channels driven.

255 watts per channel into 8 ohms at less than 0.025% THD from 20 Hz to

20 kHz with both channels driven.

800 watts into 8 ohms at less than 0.04% THD from 20 Hz to 20 kHz in

monophonic bridged operation.

IM Distortion (SMPTE): Less than 0.007% from 1 watt to 225 watts, each channel, into 8

ohms.

Typical THD at 255 watts into 8 ohms:

Frequency Response into

Typical Channel Separation at 1
Signal to Noise Ratio: Exceeds 100

Input Impedance: 47,000 ohms, in parallel with 50K ohms input level control.
Input Sensitivity: 2.35 volts for 255 watts into 8 ohms; 0.14 volt

2 volts for 400 watts into 4 ohms; 0.08 volt for

Damping Factor: 200 to 1 kHz into 8 ohms; 60 to 10 kHz into 8 ohms.
Rise Time: 10 kHz, 80 volts p/p square wave, 10% to 90%: 2.5µs.
Slew Rate: 1 kHz, 120 volts p/p square wave, 40
Semiconductor Complement: 27 transistors, 12 power MOSFETs, 33 diodes, 8 zener diodes,

Power Consumption: 240 VA quiescent; 1200 VA @ rated power into 8 ohms, both channels

Size: 7” high plus
Net Weight: 48 lbs.
Shipping Weight: 52 lbs.

1/4”

8

ohms: -3 dB, 2 Hz to 120 kHz at 1

kHz:

dB

Exceeds 90

driven.

feet, 19” wide, 13” deep plus 1” for handles.

dB

1 integrated circuit, 1 diode bridge.

1

kHz: 0.002%

10 kHz: 0.007%

watt.

±0.5 dB, 5 Hz to 40 kHzat255

65

dB

referred to 255 watts into 8 ohms, unweighted.

referred to 1 watt into 8 ohms, A weighting.

V/µS.

watts.

for 1 watt.

1 watt.

WARNING: TO PREVENT FIRE OR SHOCK HAZARD, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
CAUTION: For continued protection, replace the power fuse only with the same type and rating as indicated.

INTRODUCTION

The P505 is a high power two channel audio power amplifier
designed and constructed for professional sound applications. It
can deliver very high power into 4 ohm loads, simultaneously
maintaining a level of performance normally associated only
with ‘state of the art’ amplifiers of lesser power capability.

The rated continuous power output from each channel is 400

watts into 4 ohms. The short term continuous power is in excess

of 500 watts per channel into 2 ohms. This is more than

enough to disable most loudspeakers if improperly applied.

Moreover, the conservative rating method we use, and the
design factors which contribute to its excellent sound and
superior low impedance drive capabilities, necessitate a word of

caution about its peak power potential. Peak power outputs
can be more than double continuous ratings. Each channel is

capable of delivering more than 20 amps into a short circuit!
And, in monophonic applications, the P500 can deliver in
excess of 800 watts continuous power into 8 ohms. Such
reserves of power must be treated with understanding, as the
Hafler Company will not be responsible for misuse, or

consequent loudspeaker damage.

Distinctive features of the P505 reflect the focus of this design

on the specific needs of the professional sound installer. Ease of

installation and setup, through attention to the smallest detail, is

coupled with overrated components, and rugged construction to
deliver ‘workhorse’ dependability. The choice of notably
rugged design binding posts for load connection allows for a

¾”

choice of wiring termination, and they are on

centers to

facilitate the use of dual banana plugs. The mono-stereo
bridging switch is on the back panel, not hidden inside. A
choice of input connectors is provided for. Air filters and
loudspeaker fuses may be replaced quickly without having to
dismount or open the amplifier. The Hafler ‘total design’
approach minimizes your time and cost of installation and
equipment service, and provides a high level of protection to
associated equipment and operating personnel.

The P505 incorporates a number of protective devices.

-

Separate power supply fuses for B + and B

on each channel,
individual thermal sensors on each heat sink, a relay to
disengage the output if excessive DC offset is detected, a delay
to avoid turn-on transients, and accessible output fuses on the
back panel to protect the load are in addition to the AC line fuse,
which must be located inside to conform to safety codes.
Connections and variable controls are located on the back panel,
secure from accidental manipulation. The front panel bears only

the power switch with its combination pilot lamp and over

temperature indicator.

A major factor in the P505’s superiority is the choice of
power MOSFET devices as the output interface between the
signal and the load. These transistors exhibit intrinsic
self-regulating characteristics that serve to protect both the
amplifier and the associated equipment against damage due to
overheating or inadequate current limiting. The benefits over

-

conventional circuitry are obvious

the prorectlve circuitry
which is a chief cause of extraneous signals in traditional
designs is eliminated, and you have greater reliability from a
simpler design.

The P505 retains the time-proven design parameters that have
established the Hafler reputation for exceptional amplifier
performance: complementary push-pull circuitry, direct
coupling beyond the initial input, all silicon discrete devices,
minimal use of feedback, conservative specification of all
components, and a carefully distilled circuit topology. You can
expect the manufactured product to consistently deliver the
same high standards of power output, low distortion and low
noise normally associated with laboratory prototypes.

Thank you for purchasing this Hafler amplifier. Our
Technical Services Department is available to answer any
questions at [phone]. We are here to see that your
experience with Hafler products is satisfactory and profitable in
every way.

P505 POWER AS A FUNCTION OF IMPEDANCE

POWER PER CHANNEL

BOTH CHANNELS DRIVEN

3

Adequate ventilation is a primary consideration when

filters

installing any high power amplifier, because of its appreciable
heat output. Cool air is drawn in through the foam filters on the
sides, and the warm exhaust is to the rear. Make sure this flow is
not impeded, and do not allow the system to work in a closed

-

box. The filters must be kept clean

just slip them out, wash
them, and squeeze dry. Replacements are available from the
Hafler Company, but if you choose to obtain them locally, make
sure you use ‘open cell’ foam for air conditioner filters.
Amplifiers supplied for overseas use with line voltages above

-

200 VAC use a different fan than those intended for 100

120
VAC. If conversion to the other line voltage range is indicated.
be sure the correct fan is obtained from the factory. See “AC
Line Connections for Overseas Use.”

CONNECTIONS

The front panel is designed for mounting in a standard EIA

19” wide rack, using four

#l10-32

screws and countersink
washers. It is sufficiently rigid to support the P505 safely. The
panel is slightly under the 7” height to allow clearance between
adjacent units. The feet may be unscrewed from the bottom to
facilitate such installation.

A power transformer of this size will radiate a noticeable hum
field, even though Hafler transformers are specially engineered
to reduce this effect. If the amplifier is likely to be installed
close to equipment which may be sensitive to such a field, such
as microphone amplifiers or other high gain audio stages, be
sure you have adequate separation.

AC Line

A 3-wire grounded power cord is provided on the

P50.5.

It
must be connected to a properly grounded (earthed) AC
receptacle for your safety. Never break off the ground pin on the
plug to avoid obtaining the proper adapter for 2-wire
receptacles. Do not use cords which are frayed, or whose plug is
damaged. Do not disconnect by pulling on the cord. Grasp the
plug itself.

High power output puts heavy demands on the supply wiring.
Each P505 requires 15 amperes (at 120 VAC) for proper
operation. A separate 20 ampere line is recommended. If
extension cables must be used, keep them short, and use #14
gauge or heavier 3-wire cord.

Input

The amplifier is supplied with standard 2-circuit (tip-sleeve
or T-S) ‘phone’ jacks for normal unbalanced input connections.
These use single conductor shielded cable (shield connected to

the sleeve), or you may choose two wire shielded cable. With
two wire cables, and an unbalanced input, the signal, or ‘hot’

(black) lead connects to the plug tip and the ground (white or
red) lead connects to the sleeve. Hum is usually minimized in
two wire cable by connecting the shield to the ground wire at
one end only.

¼’ PHONE PLUG

I

SLEEVE

INSULATING

SHIELD

GROUND LUG

PLUG BODY

\

MAY BE CONNECTED

(see TEXT)

SHIELDED CABLE

TO

If very long input signal cables are required, a balanced input

is usually advisable, using two wire shielded cable, and adding

the Hafler BL500 option, which eliminates the need for

hum-sensitive external input transformers. Then the 2-circuit
(T-S) phone jacks may be replaced by 3-circuit (tip-ring-sleeve
or T-R-S) jacks, wired with the ‘low’ (white or red) lead to the
ring, and the shield to the sleeve. Or, 3-pin ‘Cannon XLR’

connectors may be installed via the chassis knockout provided.

The XLR connectors are often preferred for either balan

ced or
unbalanced lines because of a locking provision. Because there
are two wiring standards, you want to make sure all your

equipment is consistent. The IEC International standard
connects the shield to pin # 1 and the signal (‘high’ - black wire)

-

to pin #2. On a balanced line, the return (‘low’

white or red
wire) would go to pin #3. The defacto American standard,
which is not as widely used, interchanges the connections to the
#2 and #3 pins.

Some applications may require the use of an input
transformer, to convert balanced lines to unbalanced
connections ahead of the power amplifier. Such transformers
are very sensitive to magnetic fields, such as those generated b

y
the power transformer. You may have to install them a fair
distance from the P505 to avoid hum pickup.

Output

The red and black binding posts were chosen for heavy duty
construction to handle the high currents which may be involved.
They are spaced for dual banana plugs, or you can connect bare
wire ends through the vertical holes in the shafts, which are
visible when the cap is unscrewed. To be certain that no wire
strands are unsecured, a tinned end, or a spade lug soldered to
the wire is recommended.

4

Maintain a consistent polarity with respect to the ‘hot’ and

‘

ground’ wires to the speakers. Most dual banana plugs have a

tab identifying one side, which is customarily made the

‘ground’ side. In stereo speaker installations it is important to
keep consistent phase relationships to preserve low frequency
response and stereo ‘imaging’ perspective. This means that the
same wiring ‘sense’ should be followed when wiring each
speaker.

DUAL 6AWAMA PLUG

SINGLE BANANA PLUG

SPADE LUG

The black output terminals may be connected together
(common ground) when accessories utilizing a common ground
system, such as headphone junction boxes, are employed.

However, the red terminals should never be connected

together. Thus you should carefully check connections when
using a common ground device, to be sure there is no reversal of
the ground and high side.

Connecting Cables

The permissible cable length for an unbalanced input is
determined by two factors: the cable capacitance per foot, and

the output impedance of the signal source, which is a function of
the design of the output stage of the source (control center).
Cable capacitance is part of the ‘load’ on the signal source. As
the capacitance increases, the effect is that of a progressive filter
which rolls off the high frequencies before they reach the power
amplifier. The amount of the roll off increases as the output
impedance goes up. With most control centers and normal input
cables (under 20 feet) the filter effect will be above the audio
range. If the output impedance of the source exceeds 500 ohms
at 1000 Hz, a high cable capacitance may cause oscillation in
the source equipment. Shortening the cable, or choosing a
special low capacitance cable type may solve the problem. If
very long signal cables are required, converting to a balanced
input is the best solution. The Hafler BL500 balanced input
option may be installed in the P505, and avoids the need for

hum-sensitive input transformers.

The choice of shielded wire for input cables may involve

more than just the capacitance per foot. Where resistance to
abuse is a factor, the rubber-clad cables with woven shielding
outperform vinyl coverings. The vinyl insulation is usually
supplied with a foil shield which can be easily tom, so plugs

must be wired with great care. If permanent wiring involves

‘fishing’ cables through conduits, the vinyl cable is easier to use
because it has less surface resistance, but the foil shield is
susceptible to splitting with undue stress.

Some thought should also be given to selecting the output
cables. When high power is demanded from the amplifier, the
impedance of the output cables becomes part of the loudspeaker
load. The desirably high damping factor of Hafler amplifiers,
which is an index of the amplifier’s ability to control the
speaker, is reduced by excessive cable impedance. Even more,
long runs of inadequate wiring waste power. The following
chart illustrates typical power dissipation with a 4 ohm load.
The lowest gauge, or heaviest practical wire size is always
preferred. When very long output cables are required, the use of
balanced 70 volt lines is recommended. The Hafler LX250
transformer can provide a 70.7 volt output from one channel of
the P505. The rated available power per channel is the
equivalent of its 8 ohm output of 255 watts. Predrilled holes in
the amplifier’s cover can accomodate two transformers. The
output voltage of a P505 operated in the monophonic bridged
mode is sufficient to drive a 70 volt line directly without the
need for a transformer.

@

Wire Gauge Power Loss in Watts

(A.W.G.)

6

10
14

18

25’ cable

1.8

4.4 17.3

11.1

26.8 91.2

4 ohms

100’ cable

6.9

41.3

Monophonic Operation (Bridged Mode)

When very high power is desired, the P505 can be switched to

a single channel amplifier, capable of delivering more than 800
watts into an 8 ohm load. For this, the Stereo-Mono slide switch
is moved to Mono, and an input signal is applied to the Left
i

nput jack only. The two output leads are connected only to the

Red terminals, and no connections are made to the black

-

terminals. The output must be ‘floating’

that is, neither side

can be grounded, as both are ‘hot’ with respect to chassis

)

ground. The red terminals are identified ( +

and ( - ) simply for
phasing reference. In this mode, the P505 can drive a 70 volt
distribution line directly. Sensitivity is adjusted by the Left
input level control.

5

OPERATION

#AF002.

Type AGC, or 3AG

Press the power switch to the right to turn the amplifier on.
Operation will be signalled by the illuminated lamp in the
switch. If it does not light, the most likely cause is a blown AC
line fuse. That is the single fuse close to the switch inside the
chassis. However, since that fuse is a 15 ampere slo-blo (for 120
VAC lines) and a common branch circuit is also rated at 15
amperes, check the main fuse or breaker panel first.

Standard practice is to turn power amplifiers on last, and

switch them off first, in the electronics chain. This minimizes
annoying noise bursts, or the likelihood of damage to the
speakers from turn-on transients generated by source
equipment. The P505 provides built-in protection from such
transients by incorporating a delay of 3 seconds at turn-on,
before the relay connects the speakers. Some source equipment

may not be silent within 3 seconds, so if you wish to extend the
P505’s delay time, contact the Hafler Technical Service
Department.

The relay serves another purpose - to protect the speakers in
the event an unsafe DC voltage appears at the output. Then the
speakers will be disconnected until the voltage drops to a safe
level. Very high levels of very low frequency energy can
sometimes imitate DC at the output, and might activate the relay
inappropriately. If this is the case, the level of DC protection
provided by the relay can be changed. Contact the factory for
assistance.

Back Panel Controls

An input level control adjusts the sensitivity of each channel.

They are usually left at full clockwise rotation, for maximum

sensitivity and best signal to noise ratio. Then 2 volts will drive
each channel to full output (4 ohm load). These controls have a

dB

‘B’ taper, with a reduction of 6

at 50% rotation.

The ‘Stereo-Mono’ switch selects either normal two channel

operation, or a combined utilization of both channels, which

sends a single input signal through the entire amplifier, and
provides a monophonic ‘bridged’ output across the channels, at
very high power. In the Mono mode, only the Left input and the

Left level control are operative, and the load is connected to the
two Red outputs only. Never make any connections to the black
output terminals in the mono mode. Note that the amplifier’s

specified power output capability in the mono mode is at a
higher load impedance than for stereo operation.

The ‘Float-Chassis’ switch determines the ground (earth)
path of the signal ground. It is normally set in the ‘Chassis’
position, where it is tied directly to the chassis ground. In some
instances, such as where several components are mounted in a
rack, ‘ground loops’ may introduce hum or increased noise.
Moving this switch to the ‘Float’ position may improve this
condition. In this position the signal grounds are referred to the
chassis through a 0.01 mfd capacitor.

Switch settings may be safely changed while the power is on.

If the pilot lamp should ever blink (2-3 times a second) this
signifies that a protective thermal breaker has shut down the
amplifier because of excessive heat sink temperature. The fan
will continue to operate at its highest speed, and as soon as the
heat sink temperature has declined, the amplifier will
automatically return to normal operation. If such a shut down

recurs, you should check for inadequate ventilation, or an
excessive input signal, an extremely low load impedance, or an
input with dangerous signal content (such as oscillation).
Failing any such indication, the fan or the amplifier may require

service. Because of the effective fan cooling, any normal signal

will not cause the amplifier to overheat.

Testing the amplifier to its limits with laboratory signals may

exceed the capacity of a 15 ampere circuit, and may require
higher fuse ratings under severe load conditions. If a back panel
speaker fuse blows, some distorted sound will be heard. Always
check those fuses first. When performing tests at high power
levels, line voltage losses need to be compensated for, or taken
into consideration. Likewise, an inadequately sized line may
suffer voltage drops which adversely effect other electronics
when high power demands occur.

Air filters

The air intake filters should be kept clean to allow maximum
cooling of the amplifier. The protection they provide against dirt
maintains efficient amplifier operation and extends reliability,
so they should not be discarded. They are easily slipped out for
washing in a mild detergent solution, rinsed, and squeezed dry.
They are made of a flame retardant material having a specific
porosity, so exact replacement is best. They may be ordered
from the Hafler Company as part #AF002.

Speaker Fuses

The two fuse holders on the back panel protect the speaker
load from excessive drive signals. They are in the feedback loop
from the output stage. When one of these ‘blows’, a distorted
signal will be heard at greatly reduced level. It is to your
advantage to choose a fuse size appropriate to your speakers,
since the P505 can deliver more power than most speakers can
safely tolerate. The David Hafler Company cannot be
responsible for damage to the loudspeakers or the amplifier
resulting from improper fusing.

If the manufacturer of your speakers recommends a fuse
rating, you should install that value in the back panel holders.
When purchasing replacements, do not use the ‘slo-blo’ type.

Type AGC, or 3AG series are suggested. The P505 is shipped

with 10 ampere fuses installed. This is the maximum value, and

will provide no speaker protection, allowing full power testing.

A pair of spare 5 amp fuses is supplied for some protection at
lower power.

There is a distinct difference between fuse ratings for
continuous power and for intermittent ‘peak power’ needs. A 2
ampere fuse with an 8 ohm load permits continuous power up to

32 watts, but will sustain intermittent musical peaks to the

maximum power output. A 3 ampere fuse permits 72 watts
continuously into an 8 ohm load, or a steady 36 watts into a 4
ohm load. A 5 ampere fuse allows 200 watts into 8 ohms, or 100

watts into 4 ohms. Thus even a 5 ampere fuse provides very
little speaker protection.

When the amplifier is operated in Mono, both speaker fuses
are in the circuit. If only one is blown, it is advisable to replace
the other as well, since it has also been stressed to the breaking
point.

6

1 oov.

AC LINE CONNECTIONS FOR OVERSEAS USE

The power transformer supplied in P505 amplifiers sold in the
USA is intended for 120 volt, 60 Hz operation only. For use in
other countries, a multi-voltage transformer is supplied in
Export versions, available at higher cost. It has dual tapped
primary windings which can be connected in series or parallel
combinations for 100, 120, 200, 220 or 240 volts, 50 or 60 Hz
power lines. The Export version includes an additional terminal
strip to terminate the extra transformer leads. In units supplied
for 200 volt and higher AC lines, the line fuse is a 7 ampere
slo-blo type, and a different fan is installed, along with different
fan controlling power resistors, which are mounted on the
underside of the audio module.

The diagrams below show schematically and pictorially the
alternative wiring for different supply voltages.

TR401

TE401

_

Te402

T

120v.

TEOl

TE401

1,

)34”I

T

Tl3401

Te401

TR401

-

TR401

-

TWO2

TB402

T?402

I -

BK

TO SW.

JII

120v

240V.

TO SW.

TROUBLE SHOOTING HINTS

Check the speaker fuses first when there is little or no sound.
A blown fuse will pass a low level distorted signal. If the pilot
lamp is steady. excessive DC at the output may be holding the
relay open. If the lamp blinks, then the thermal protective
circuitry has shut down the amplifier.

Always check external factors such as cables and signal
sources before dismantling the P505. Once the cover is
removed. do not attempt to move the amplifier by the front
panel handles! Check the internal fuses. The line fuse is near the

The

power switch.

-

‘rail‘ voltage. Failure of any of these indicates a circuit

B

two dual fuse holders monitor the B + and

problem. unless the amplifier was undergoing very high power
tests into a low impedance load. where the fuse sizes may need
t

o be increased.

If the amplifier requires factory service, and the power
transformer output appears normal when its secondary leads are
disconnected from the diode bridge, the transformer can be
removed, and the rest of the amplifier returned for service. This
greatly reduces the cost of shipping, and the risk of damage in
transit. If you have isolated the fault to the audio module. you

may prefer to disconnect it. and return it as a unit (fan. heat
sinks, circuit boards). Four screws secure it to the chassis. Be
sure you tag every wire as you unsolder it. When packing it,
wrap it first to prevent particles of packing material from
becoming trapped, and provide plenty of cushioning.

120volts~tdDeakintoIduninserieswith

loo Hz

PC-19c

d&O-

-~-m

03

40

rr__’

50 a0

\‘\

7

0.8

PC-19 COMPONENTS

SQUARE WAVE RESPONSE WITH A REACTIVE LOAD

120 volts peak to peak into R ohm resistor in parallel with

&-

@am0

1

mfd.

8

CIRCUIT DESCRIPTION

Amplifier stages are fully direct coupled (DC coupling). w ith
a dual differential pair for the input, and a fully complementary
MOSFET output stage. Transistors Q3. Q4, Q5 and Q6 form the

while

differential input,
for the input pair. Potentiometer PI adjusts the output offset
voltage.

Transistors Q7, Q8 . Q10 and Q11 form the second gain stage,
and are the ‘predrivers’ for the output stage drivers Q12 and
Ql3.

An adjustable voltage reference is formed by transistor
and potentiometer P2. The signal ‘sees’ the bases of transistors
Ql2 and Q 13 tied together.
amplifier for Class AB operation, and therefore determines

quiescent (idle) current in the driver and output stages. Thermal

stability is assured by the positive temperature coefficient of the
MOSFETs.

The output stages are also fully complementary. Q401. Q402
and Q403 are N channel MOSFETs connected in parallel for the
positive half of the signal. Q404. Q405 and Q406 are P channel
MOSFETs for the negative half.

Ql and Q2 are constant current sources

Q9

P2

adjusts the voltage to bias the

the

There is none of the usual volt-amp limiting in this design.

D12

Diodes D111.
MOSFETs from being ov erdriven in the event of excessive
signal levels. The output current is limited by the B + and B
fuses and the speaker fuses.

A protective relay circuit has a j-section low pass filter which

prevents signals above 10 Hz from triggering the relay. This
circuit allows direct current to pass to IC101. which senses any
offset above 3.5 volts and then opens the relay to protect

load. RI06 and R107 form the reference for the positive offset
detector portion of IC
detector. The charging time of C104 is the delay time at turn on.

D1O6 and C105 produce a rapid discharge supply that opens the
relay instantly when the amplifier is turned off.

An overload protection system includes thermal breakers on
the heat sinks which will turn off the amplifier if overheating
occurs, and thermal sensors which will bypass fan-limiting
resistors as the temperature rises. increasing the
current inrush limiter TR401 is located in the AC line input.

, D13 and D14 prevent the gates of the

10

1. R108 and R

1O9

act for the

negative

fan

speed. A

-

the

IC40

1
LI
PI
P2 1000 ohms trimpot
P401 50.000 ohms. level control
T40

I Power Transformer
T402
RY4OI DPDT relay
S40

1

LM339N
Inductor. I .4uH

1000 ohms trimpot

Power Transformer multi-voltage

Power switch

QBI

I5

TAI

I2
RPOI I
RPOI I
RF036

TAI

I6

TAI

I7

SZI

13

SLIII

s402
S403

TR40

TR402
TR40
TS40
TS402

DPDT slide switch
DPDT slide switch

I

I

Thermal breaker
Thermal breaker

Inrush limiter

I

Thermal
Thermal sensor

Fan,

Fan,

sensor

I20

volt

200-240

volt alternate

SZl22
SZl22
SF024

SF024

RZOl6

SF025
SF025

AAI

I4

AA129

SCHEMATIC

P505

Power Amplifier

©

Copyright 1985, All rights reserved.

DIAGRAM

r

11

SERVICE POLICY AND LIMITED WARRANTY

The PS0.5 Power Amplifier has been carefully engineered to
provide many years of trouble-free service. Every unit is tested
before and after a 24 hour ‘burn-in’ under load. ensuring that
any marginal component or operating condition is corrected,
and that all operating parameters are stabilized before the unit is
released for shipment.

If a problem arises,
factory service facilities. Many of the components in the
are not readily obtainable in the field. and performance is likely
to suffer by the use of ‘similar type’ substitutions.
Service is provided for all Hafler Professional products.
Requests for technical assistance or parts replacements may be
telephoned to [phone] from

on weekdays. Please have the unit serial number at hand. While

we are glad to help. we do not recommend that you perform
your own service unless you have considerable technical

experience.

It is the owner’s responsibility to ship the unit prepaid to the

service

factory

facility. Collect shipments will be refused. Use
the complete original carton and all packing materials to ship the
amplifier. Enclose the following information:

1. The complete return shipping address. (Post Office box
numbers are acceptable only for correspondence, not for
shipment). A daytime telephone contact may be helpful if our
service department has any questions.

2. The unit serial number.

3. copy of the bill of sale, if service is expected
warranty.

4. A description of the malfunction, under
occurred. and whether it is intermittent.

we urge you to take advantage of the

P505

Priority

8AM

to 4PM eastern time

under the

what conditions it

You are responsible for proper packing. Insure it for the retail
value. United Parcel Service is suggested for domestic
shipments, and is the usual carrier for its return. Units which
required service under the warranty will normally be returned by
UPS prepaid, within continental USA. Other return shipments
will be at the owner’s expense. All service work is guaranteed
for 90 days.

If you choose. you may return only the complete audio
module for service. if the fault has been isolated therein. It
should be insured for $400. Or, you can remove the power
transformer to reduce weight and the likelihood of damage in
shipment. See “Trouble Shooting Hints”. Unsolder, do not

cut, transformer leads in particular, for the transformer warranty

is voided if the leads are cut too short for re-use. The Hafler

Company will not be responsible for consequential damage
caused by removal and/or reinstallation of the module or
transformer.

WARRANTY

The P505 is warranted for three years from the purchase date.

including parts. labor and normal return shipping costs from the

service facility to the owner, within the continental USA. The
owner

is responsible for shipment to the service facility. and
must submit a copy of the dated bill of sale. Warranties apply to
t

he original purchaser only. The warranty is void if the P5O5 has
been modified without factory authorization. or if it has been
electrically or physically abused, or if it has been used for some
purpose for which it was neither designed nor intended.

This warranty gives you specific legal rights.

have other rights which vary from state to state.

You may also

Prlnted In

USA