DC
OFFSET
ADJUSTMENT
©
Cyrus
Audio
Ltd
Jun
2014
18
Cyrus
6
DAC,
Cyrus
8
DAC
service
manual
Issue
1
DC
offset
adjustment
(no
signal
condition)
The
DC
offset
adjustment
sets
the
DC
voltage
at
the
speaker
output
terminals.
DC
offset
should
always
be
checked
as
a
matter
of
routine
when
an
amplifier
is
returned
for
repair,
whether
the
power
amplifier
section
has
required
repair
or
not.
The
following
procedure
should
be
followed
exactly
to
set
the
DC
offset
voltage
to
the
correct
value.
If
the
DC
offset
voltage
will
not
set
correctly,
this
may
indicate
a
power
amplifier
fault.
Switch
off
the
power
to
the
amplifier.
Disconnect
all
loudspeakers
or
dummy
loads.
Connect
a
DVM
set
to
read
mV
to
the
left
loudspeaker
terminals
(a
short
cable
terminated
with
Cyrus
speaker
connectors
is
recommended
to
make
certain
contact
with
the
terminals).
Switch
on
the
power
to
the
amplifier,
and
bring
it
out
of
standby.
Set
the
volume
level
to
‐
15dB.
Leave
the
amplifier
to
settle
for
5
minutes.
Check
the
voltage
reading
on
the
DVM.
A
voltage
within
the
range
0V
50mV
is
acceptable
and
will
not
require
any
adjustment.
If
the
voltage
is
outside
of
these
limits,
adjust
RV203
to
set
the
left
channel
offset
within
the
range
0V
50mV.
Connect
the
DVM
to
the
right
channel.
Repeat
the
voltage
check
to
the
same
limits
and
adjust
RV204
to
correct
the
right
channel
offset
if
necessary.
Leave
the
amplifier
to
settle
for
15
minutes
and
re
‐
check
the
DC
offset
voltages.
0.0mV
RV204
RV203
