Luxman 308 - Page 12

CARTRIDGES
Types
There
are
various
types
of
cartridges:
magnetic
type,
photo-
electric
type.
electrostatic
type
and
piezo-electric
type.
Most
predominate
is
the
magnetic
type
which
includes
the
MM
(Mov-
ing
Magnet),
the
IM
(Induced
Magnet).
the
MI
(Moving
Iron)
and
the
MC
(Moving
Coil).
The
PHONO
terminals
of
this
ampli-
fier
are
designed
to
match
with
these
types
of
magnetic
car-
tridges,
but
a
cartridge
of
low
output
level
(output
voltage
0.01
to
0.1mV)
cannot
be
directly
connected.
(Refer
to
the
Step-up
Transformer
for
MC
Type
paragraph.)
lf
using
the
photo-electric
or
electrostatic
type
cartridge.
choose
appropriate
input
terminals
according
to
the
explanation
sheet
of
the
cartridge.
Among
the
piezo-electric
types,
there
are
crystal
types
and
ceramic
types.
Generally,
these
types
can
be
connected
to
the
AUX
terminals,
but
the
equalizer
characteristic
will
be
incorrect
(further
equalization
will
be
needed).
For
this
reason,
they
are
seldom
used
in
high
class
units.
Input
Impedance
The
PHONO-1
input
terminals
(24)
are
coupled
with
a
3-step
(50Ka,
65KaQ
and
90Ka)
impedance
selector
(25)
on
the
rear
panel.
Except
fora
special
low
impedance
type
cartridge,
almost
all
currently
marketed
cartridges
specify
recommended
load
impedance
of
30/1
OO
Ka.
tn
this
range,
the
cartridge
with
a
65Ka
load
impedance
is
by
far
predominate.
It
is
known
that
variation
of
the
load
impedance
value
affects
the
frequency
response
to
a
great
extent.
The
graph
shown
here
illustrates
this
point.
Notice
that
a
low
load
impedance
cuts
treble
output,
while
a
high
load
impedance
causes
a
peak
in
the
treble
range.
The
degree
of
such
effect
is
notthe
same
with
different
cartridges,
but
generally
a
cartridge
having
a
higher
output
impedance
tends
to
be
more
delicately
influenced.
It
is
therefore
necessary
that
selection
of
a
proper
input
impedance
is
made
with
this
control.
5d8 :
5dB
~ BOHz 100Hz
a
aan
aInaESsnIn
ann
|
|
Step-up
Transformer
Unit
for
MC
Type
Cartridges:
:
This
amplifier
does
not
have
connectors
for
exclusive
use
of
a
step-up
transformer.
However,
if
input
voltage
step-up
is
desir-
ed,
use
of
the
LUX
mode!
6521S
pin-plug
step-up
transformer
unit
is
recommended.
This
completely
new
step-up
transformer
is
extremely
compact
and
features
highly
efficient
performance.
Fitting
of
this
transformer
to
the
amplifier
is
accomplished
through
the
PHONO
terminals.
By
using
this
transformer,
low
output
level
phonograph
signals
from
a
MC
(Moving
Coil)
cartridge
can
be
boosted
by
30
times.
The
core
of
the
transformer
is
made
of
super-permalloy
material
to
ensure
superb
frequency
response.
Bisection
winding
coil
construction
and
complete
shielding
provision
for
the
core
perfectly
eliminate
induced
noise
from
external
sources.
Specifications
(6521S
trans
unit,
2
pes.
&a
pair)
Primary
end
impedance
Less
than
40
Secondary
end
impedance
More
than
30Ka
Step-up
ratio
138
Frequency
response
40
to
30,000Hz
Output
voltage
distortion
500mvV,
0.02%
Induced
noise
level
Less
than
—80dB/m
Weight 12 grams
tkKHz 7’ BH SS*«*WT' KHZ
Effect
of
the
Load
Impedance
on
the
frequency
response.