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
choice of wiring termination, and they are on ¾ ” 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.
P505 POWER AS A FUNCTION OF IMPEDANCE
P
O
W
ER P
ER
CHANNEL
BOTH CHANNELS DRIVEN
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 (609) 662-6084. We are here to see that your
experience with Hafler products is satisfactory and profitable in
every way.
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