Owner's Manual
Table Of Contents
SETUP
Connect
the source
to
the input
of
the unit
and
select the balanced
or
unbalanced
input in appropriate. Plug your headphones
into
one
of
the front panel jack
according
to
the impedance rating
of
the headphones. Set the volume
to
minimum,
connect the
unit
to
the main supply
and
switch
on
. It takes
30
seconds
or
longer
to
warm
up
before you can use it.
This PA-One
is
able
to
drive both high
and
low impedance headphones.
'High
impedance'
means 1 OOohms
and
above;
'low
impedance'
is
below
1 OOohms. (Typically,
high
impedance
headphones
are
200ohms
or
600ohms,
while
low
impedance
types are 32ohms.) A specification
for
impedance
will normally be included in the instructions that
come
with the headphones,
or
you can judge the
impedance
type
of
your headphones by
following
the steps below.
Connect
your
headphones
to
a low
impedance
('Low Z') socket.
Turn
up
the volume slowly while listening
to
a
familiar
music track. If the volume seems low, even at
maximum
volume, your headphones are
probably
high impedance.
Turn
the volume
down
to
minimum
level
and
reconnect the
headphones
to
a high impedance
('Hi
Z') socket.
Turn
the volume
up
slowly
again
and
check that the volume if it
is
satisfactory.
High
impedance headphones will clearly play
louder
when
plugged
into
a high
impedance
socket. Low
impedance
headphones
will play slightly
louder
when
plugged
into a low impedance socket.
Interconnect cables should at low capacitance
and
well screened. Avoid excessively
long
cables.
CAUTION
The volume should be set
to
minimum
when you switch
on
the unit.
When
the unit
is
playing a music track, adjust the volume
knob
slowly
and
keep the volume at a
comfortable
level. Listening
to
the
loud
sound
for
a long
period
can
damage
your hearing
permanently. If you feel
uncomfortable
while listening,
or
if
there
is
a whistling in your ears after a listening session, you may
listening
too
loud.
Turn
the volume
down.
There are
no
user adjustable settings inside the unit. Please
do
not remove the
top
cover
as
this will expose high voltage parts
which present a
danger
to
life.
The unit generates heat while working, so it should be placed in a well ventilated position,
and
enough space
is
required behind
it
to
ensure that leads are npt unduly strained
or
damaged
.
Very frequent switching on
and
off
in any electronic equipment put some stress
on
components, particularly in the
power
supply.
The unit should be switched
off
when at night
to
save electricity
and
to
maximize
operating
life
of
the valve.
Do
not plug in the charged case headphones, earphones
or
may cause
damage.
TECHNICAL
FEATURES
It uses 6SL7 valves,
and
uses
6SN7
valves
as
the
enhanced
drive
of
'triode
mode',
properly
matched
to
the
load
through
different impedance taps
of
high-performance
audio
transformer, which can be adjusted by the switch,
to
delivers nearly 1 W
of
high quality, low distortion
power
into
high
or
low impedance headphones.
The use
of
EZ81 valves
as
rectifier makes the sound very soft
and
gentle, which
is
more
suitable
for
headphone
listening.
It
can
also be used
as
pre voltage
amplifier
due
to
its function
of
pre output. The circuits use cathode feedback instead
of
negative
feedback
loop,
contributing
to
a very small distortion
and
well
dynamic
performance.
With the function
of
USB, coaxial
and
optical input, they can be connected
to
sources
from
computer
or
other
devices. It
is
manually welded with unique
manual
craft.
All
components in the
amplifier
have been carefully selected
to
give consistent high performance over a
long
period.