Yamaha CS-80 - Signal Processing

and you
suspect
some control(s) was
accidentally
moved,
don't
panic; just go to a
preset
while you
check the
panel
levers
and switches.
TIPS
ON
AUXILIARY
SIGNAL
PROCESSING
Phasers,
echo
boxes,
reverbs, digital
delay
lines,
parametric
equalizers,
fuzz boxes,
wah-wah
pedals,
graphic
equalizers,
etc. are
all auxiliary
signal
processing
devices
that may be
used
with
a
synthesizer.
The synthesizer
output
is
higher in
level than
most
electric
guitar pickups,
but it
can
still be
plugged into
many guitar-type
pedals and
boxes if
the
HIGH/LOW
switch is at
LOW
and
the
Volume
control
is
set
at
a moderate
level.
On
the
other
hand, it may be
better
to
use an
external
attenu-
ation
pad to
match
the
level of
the
synthesizer out-
put to a
high-sensitivity
(low level)
effects
device.
Signal
processing
equipment
made
to
interface
with
studio
equipment
can usually be
driven
directly
from the
synthesizer
output
with the
HIGH/LOW
switch in
HIGH position. In
all cases it is a
good
idea
to
check the
level (sensitivity)
specifications
for
the
auxiliary
signal
processing
unit against
the
synthesizer
specifications.
Many of
the
sounds you
might
wish to
achieve
with
an
outboard
effects device
can actually be
achieved
with
controls and
circuits that
are built
into
the
synthesizer.
For
example,
tremolo,
vibrato
and
wah-
wah can all be
obtained
using
the sub
oscillator.
Where
practical, use
the
built-in
capability of
the
synthesizer,
since
the
sound will be
going through fewer
circuits
and
will therefore
have the
lowest noise
and
best
frequency
response.
Many
patches
are
greatly enhanced
by
auxiliary
signal
processing.
The realism of
"acoustic
"
instru-
ment patches
can
be
very
much
heightened
by
using
reverb.
The synthesizer's
External
input can
afford
some
interesting effects.
To obtain
strange
''vocal" effects,
plug
in
a
source
of
a very
pure,
high-frequency
sound,
such
as
a
10kHz
or
higher sine
wave
oscillator.*
Then
engage
the
VCF (filter)
on
the
sub
oscillator, and add
a
lot of
Resonance
[8
and/or 27 &29]
.
The
External
input is not
made
for
use
with guitars or
microphones,
and
even
if
a
preamplified guitar or
mic is used,
the
results
could
be
disappointing.
Some
preamplified
(electric)
instrument outputs
will produce
interesting
results when
connected
to
the
External input.
*The purer the
sine
wave
fed
to
the externa/ input, the
better-sounding the result
will
be.
DIRECT BOX
A
"direct-box"
is
a type
of
adapter.
In
some
cases,
rather than
connect the CS-80
directly to a
mixer,
one
could connect
the
synthesizer
to
an
instrument
amp.
The direct
box
would then
be used to
interface
the
instrument
amplifier's speaker
output (guitar
amp,
P.
A.
amp,
etc.)
with the
mic
or
line level
mixer
input,
thus
including the
amplifier's
reverb,
tremolo,
brightness
and
other
effects in
the
mix.
Another
application
for a
direct
box is to
achieve
grounding
isolation
between
an
unbalanced
line
level
output and a
balanced
mic
or
line
level
input.
The CS-80
output
has
a
low source
impedance so
that it
will drive a
low impedance
(600-ohm) or
high
impedance
input
without
adapters.
The CS-80
output
is
unbalanced,
meaning
that the
signal,
which flows
through a
single-conductor
shielded
cable, is
grounded
on one
side
(the
shield)
and
ungrounded
on the
other
side
(the center
conductor).
This
arrangement
is per-
fectly
suitable
for
cables of up
to
3
m
(10')
in
length.
When
a
longer
distance
separates
the CS-80
output
from the
mixer
input, it is
desirable
to
use
a
balanced
line
rather than
an
unbalanced
line
for
better
rejection
of
potential
hum, noise
and
interference.
In
a
balanced
line,
the
cable
shield
is
grounded,
but
carries
no
audio
signal;
two center
conductors,
neither of
which
is
grounded,
carry the
signal.
Provided
the
mixer
input is
balanced
(transformer
isolated), a
balanced
line will be
obtained
by
connecting
a
direct
box at
the CS-80
output.
if two or
more CS-80
outputs
are
connected to
one
mixer,
it
is a
good
idea to use a
direct
box
on each
output so
that
the
ground
to
all but
one of
the
inputs
can
be
interrupted
without
breaking
the
signal path.
This avoids so
called
"ground loops,"
multiple
grounding
circuits
between
the
mixer and
the
synthesizer
that
might otherwise
introduce
hum.
PAD
IN/OUT SWITCH
The direct
box
illustrated
can be
used
in three
ways,
as
indicated
below,
and its
three
switches
should be
set
as
required.
The
ground
switch breaks
the
ground
(shield
connection)
in the
XLR
output,
and
should
be
set for
minimum
hum. The
Pad drops
the
signal
level so
that
high
level
outputs do
not
overdrive
lower
level
mixer
inputs. The
Filter,
which only
works
when the
Pad
is
switched
IN, simulates
the
high
frequency
roil
off
of
a
typical
guitar
amp's
speaker.
Since
clipping
distortion
in
a
guitar amp
often creates
high
frequency
harmonics,
the
filter switch, by
lowering
high frequency
response,
also
cuts
distortion.
47
Assemble
the
unit
in
a
small metal
mini-box, and
keep
the
phone jacks
isolated
from the
chassis of
the
box. Also keep
the box away
from the
chassis
of
the
instrument
amplifier or any
other
grounded object.
if you
chose
a
transformer other
than
the
JE-DB-D,
it
should have
similar characteristics:
an
impedance ratio
of
20k-ohms (primary) to
1 50-ohms
(secondary),
dual
faraday
shields,
very low
capacitance on
the
primary
winding, and
full audio
spectrum response.
A
commercial
direct box
may
be
purchased, or a
qualified
technician
can build
one from the
schematic
diagram
shown
here.
The design, courtesy
of
Deane
Jensen
(Hollywood, CA), is
included
in this
manual
for
the
benefit
of the
synthesizer
user,
and does
not
represent an
endorsement
by
Yamaha of
the
specific
products
mentioned.
This direct box also
works
well
with electric
guitars,
maintaining good
high frequency
response
because
the pickup is
not
loaded.
The JE-DB-D
transformer
is available
directly
from:
Jensen
Transformers
1617
North
Fuller
Avenue
Hollywood,
CA 90046
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