General - HP Barney Oliver Manual

The Barney Oliver Audio Amplifier
A.

GENERAL

The
Oliver
quality all solid state audio amplifier designed for
two channel stereo
in and in small to medium sized
auditoriums. It is intended for use with full fre­
quency range 8 to 16 ohm
with signal sources
AM and FM tunners) that are themselves
flat enough to
addition to the power
phono designed to operate from any
of several phono cartridges. These pre-
the necessary equalization for
characteristic. Additional
boards, install and wire printed
Hum and distortion
result of attention to
routing on
hum is well below thermal noise (which itself has
been minimized by
The output of the amplifiers are operated
class-B to reduce standby power drain and are
biased and degenerated to reduce crossover
A
distortion. amount of overall
from over
low frequencies to over
audio range further reduces any
monic and inter-modulation distortion. Since the
E
Amplifier is a
in the
sound
(phonograph pickups,
little or no
the unit includes
are inaudible.
and to lead
circuit the residual
input
100
dB gain at de and
50
dB at the
ION I
E C
CRI TION
are direct coupled, overload
no long time constant
high simply clipped and the original waveform resumes
at its proper value immediately afterward. Be-
cause of the
only a fraction of a dB below actual overload
typically show a total distortion over
and
the fundamental.
In
amplifiers, and active filters in the
control board, enable the low-end response to be
maintained down to
rapidly below the audible range. This prevents the
and
their linear excursions by low frequency
transients
records or breath blasts into
end response is reduced at 18 dB per octave above
20
kc another pair of active filters to protect
the amplifiers
of, strong r-f signals.
The power
from accidental short-circuits at their out­
puts. Momentary shorts will have no
As a
sustained shorts may blow one or more of the pro­
tective fuses. In addition, all power
are either current limited or fused so that shorts
from test
feed-
and decay of power
of function
of the
transients in the
har-
low voltage
turn-on transient from the prla-amIJlll:leI
the
amount of feedback,
networks in the fi-circuits of the
20
Hz and to fall off very
from
from such sources as
overload or
are protected
will in cause no
considerable effort was devoted to
transients. A balanced
minimizes the tum-on
A slow tum-on in the
further reduces the
are
75
dB below
and
being driven
The
and careful
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