a-
For II7 V version:
S 6
=
2.0 Amp black
S 7
=
I.6 Amp black
AII fuses
are
of the
type
and have
the dimensions
5
x 20 mm.
The 6.3 V
heater winding of the transformer T 863,/I
provldes
the heater voltage for the two regu-
lating valves E I30 L ln the stablllzer
circult, whlch have a cathode
potential
of
+
250 V
with
respect to
chassis.
D
4b
PIug-in Stabilizer
The
stabilizer
unit contains
the
stabilizlng circuits
for the HT-voltage
for
the oscillator and the
ampllfiers.
Thls
electronic stabilizer
provides
excellent smoothing,
maintains
a constant
plate
voltage
and
makes it independent
from fluctuatlons
and surges in
the mains
supply.
This ensures
accurate
maintenance of the bias levels, The low
source
impedance of the HT-suppiy
provides
good
de-coupling of
the
ampllfier stages.
Pentodes type E 130 L
(
in trlode connectlon
)
are used as
regulating valves
and
the control volt-
age
ls amplified
by the double triode V 2
(
E 283 CC
)
in cascode clrcuit. The high amplification
factor of this valve helps to
reduce the hum level to
a
minimum.
Theupperstabilizerinthediagram
7.837,470 wlththevalves V1,2,3 supp]lestheplayback
amplifiers,
the lower one with the
valves
V4, 5,
6,
the record
amplifiers and
the oscillator.
By
means of the contacts of
the relay RAA,
and a speclal
circuit for the valve V
6,
the control
rig. L4
85A2
V3
a
<v(
o
v2
c
E283CC
V6
V5
o-.,c
E188CC
V{
valve V5 and the
regulating valve V4, comparatively
slow
voltage
rise
in the supply voltage
for
the osclllator as
well
as
for the valves
V
1.1
and V 2.
I of the record amplifier is achieved when
the
"record"
button
is operated, This
avoids any
voltage surge which
might
cause cllcks
on
urecord"
and
,/
ot magnetise the heads,
When
replacing one of the valves V I
-
5
the corresponding HT-voltage should be
tested.
The
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