Objective
2
Headphone
Amplifier
Operating
Instructions
1.
Connect
an
audio
source
to
the
Input
jack
using
a
3.5mm
interconnect
cable.
2.
Connect
headphones
to
the
Output
jack.
3.
Press
the
Power
button
to
power
on
the
amplifier.
Keep
volume
low
until
music
is
playing.
4.
Slowly
raise
the
volume
knob
to
an
appropriate
level.
See
Listening
Tips
below.
Listening
Tips
Always
use
low
gain,
unless
maximum
volume
is
insufficient
with
your
specific
equipment.
For
maximum
sound
quality,
use
a
line
level
source,
or
turn
your
audio
player’s
volume
up
very
high
(60
‐
80%).
Volume
should
always
be
controlled
from
the
amplifier.
This
amplifier
can
produce
dangerously
loud
music.
Be
sensible
and
listen
safely:
www.hearingloss.org
Troubleshooting
O2
produces
no
sound,
but
power
LED
is
on
o
Cause:
Batteries
are
weak.
o
Solution:
Turn
the
O2
off
and
recharge.
O2
turns
off
unexpectedly
and/or
produces
clicking
or
popping
sounds
o
Cause:
Batteries
are
weak.
o
Solution:
Turn
the
O2
off
and
recharge.
O2
does
not
charge,
charges
only
1
battery,
or
clicks
while
connected
to
power
adapter
o
Cause:
Incorrect
power
adapter.
o
Solution:
Use
a
14
‐
20VAC
power
adapter.
See
notes
on
reverse
side.
Distortion
at
high
gain
o
Cause:
O2's
volume
control
resides
between
its
input
and
output
stages.
Some
combinations
of
headphones
and
line
‐
level
sources
can
overdrive
the
O2's
input
stage.
Refer
to
NwAvGuy's
blog
for
thorough
explanation.
o
Solution:
Use
low
gain,
or
switch
to
a
high
voltage
AC
adapter.
Thank
you
for
purchasing
the
Objective
2
.
If
you
have
additional
questions
or
comments,
feel
free
to
contact
us
at:
JDSLabs
.com
