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Патент USA US2107125

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Feb- 1, 1933-
Original Filed Jan. 25, 1929
w 1 T N E55
Ef/VJAMl/V F. M/{as/v02
Patented Feb. 1, 1938
Benjamin F. Miessner, Short Hills, N. J., assignor,
by mesne assignments, to Radio Corporation of
America, New York, N. Y., a corporation of
Application January 25, 1929, Serial No. 334,870
Renewed June 4, 1935
4 Claims.
The present invention relates generally to am‘
plifying and reproducing systems, and more par
ticularly to such systems employing multiple
electrode vacuum tube ampli?ers having the elec
5 trodes energized for operation from ?uctuating
sources of potential and reproducing devices also
requiring energizing, such as electrodynamic re
More particularly the invention contemplates
10 ‘simplifying such systems and reducing the cost
(Cl. 250-27)
to the point a at the negative side of coil L1 as
Coil L2, the second winding on the reproducer
?eld core H, is so wound and connected in the
upper leg of that component of the ?lter system
supplying plate current to tube AT1 that its ?eld
is preferably additive to the ?eld of coil L1 in
order to meet the usual requirement in electro
dynamic reproducer operation of having a strong
Thus in addition to‘ serving as a repro
the plate current of tube A'I‘1, or the plate cir
novel manners.
cuits of a multiplicity of ampli?er tubes, as
when the amplifying system includes one or more
Other objects and advantages will be obvious
15 from the description in connection with the ?g
ures of the accompanying drawing in which like
reference characters represent like parts so far
as possible in the several ?gures.
Fig. l diagrammatically illustrates an audio
20 frequency three electrode vacuum tube amplify
ing system followed by an electrodynamic re
producer connected to embody the invention in
one form.
ducer ?eld coil it acts as a ?lter inductance for V
thereof by utilizing some of the component ap
paratus parts in a multiplicity of functions in
stages of radio frequency ampli?cation. >The 15v
winding of coil L2 may have such resistance that
by itself it reduces the potential of the output
of the recti?er tube RT a desired amount,. it
being usual to operate amplifying tubes preced
ing the last stage at plate potentials that are 20
considerably less than the plate potential of the
usual power tube in the last stage, or its resist
ance may be combined with a supplementing
Fig. 2 illustrates a modi?cation in extension
25 \of the system of Fig. 1.
resistance R4 for the purpose of obtaining the
45 condenser C1 across the output of the recti?er
C2 and C3.
required potential reduction.
Condenser C2 is an additional ?lter condenser
for the plate current supplied to tube AT2, and
tubes AT1 and AT2 are shown connected in cas
condenser 03 is an additional ?lter condenser for
cade for audio frequency ampli?cation with the
plate current supplied to tube AT1. Since the
aid of audio transformers T1, T2 and T3 in a well
?uctuating current in the plate circuit of tube 30
30 ,known manner. The tubes are shown energized
AT1 is ampli?ed in tube AT2 it is desirable to
from an alternating current source, such as a
?lter for this tube more than for tube AT2, and
commercial 60 cycle system, through trans
former having primary winding P, the ?laments the extra ?ltering in coil L2 aids to this end as
well as does making the capacity of condenser
of the tubes being heated with raw alternating
of suf?ciently large value to proportion the 35
recti?er tube RT is energized from secondary filtering as desired. If the ?uctuations from tube
windings S1 and S2, the recti?ed current from AT1 are introduced into the grid circuit of tube
which is utilized to energize the plate and grid AT2 in proper phase to oppose ‘the ?uctuations
in the plate circuit of tube A'I‘2 this proportion
electrodes of the tubes after ?ltration later to
ing is of particular value for neutralizing hum 40
40 ,be described.
Coils L1 and L2 are two coils on a ?eld core H ‘ producing currents, a feature I have fully dis
closed in prior applications of mine. This oppos
of an electrodynamic reproducer having a
ing or bucking effect permits of using condensers
movable or armature coil A, usually attached to
of capacity smaller than usual in positions C1,
a cone or diaphragm for sound reproduction. A
Referring to Fig. 1 three electrode vacuum
stores unidirectional energy and by-passes ?uc
tuations to start the ?lter system. Coil L1, in
Resistance R1 and condenser C4 serve to ?lter
the grid biasing potential of tube AT2 developed
in coil L1 alone or supplemented by resistance
the negative leg of the ?lter, acts as a ?lter in
R3, and C4 additionally serves as a low impedance
ductance in addition to being a ?eld coil of the
by-pass to the ?lament of signaling currents in 50
50 reproducer, and further may be designed with
the grid circuit of tube AT2. R2 is a grid bias
proper resistance to produce the required differ
ence of potential for negatively biasing the grid , producing potential resistance for tube AT1, and
condensers C5 and C6 serve to by-pass signal cur
of tube AT2, or to cooperate with a smaller than
usual biasing resistance R3, to this end by reason rents around this resistance and around poten
tiometer P1. Potentiometers P1 and P2 provide 55
55 of the grid circuit of tube AT2 being connected
for selecting the points of connections of grid
and plate circuits to the ?laments of tubes AT1
sound reproducer having a plural section ?eld V
winding, a source of unidirectional pulsating
and AT2, and the connections may be displaced
from the mid point or neutral for bucking of
?uctuations produced in the ?laments of one
current for energizing the output circuits of said
tubes, and a ?lter circuit connected to the posi- >
tive and negative terminals of said source in
terposed between said source andv said output
circuits, one section of said ?eld winding being
series connected in the negative line of said
tube by ?uctuations produced in the ?laments
of one or more other tubes, as disclosed in prior
applications of mine.
Tube ATz transfers the ampli?ed signals for
?lter and another section being series connected,
in the positive line thereof, said sections being
so connectedjthat the ?elds resulting from the
10 reproduction to' movable coil A of the repro»
ducer by way of transformer T3, and residual
?uctuating currents in the output of tube A'I'z ,
may be used to oppose the effect of the ?uctuat
ing ?eld'produced by ?eld coils L1 and L2 by so
15 poling transformer T3 to introduce the output
?uctuations into coil Alout of phase with the
?eld ?uctuations.
?ow of ?lter current therethrough are addi
tive,‘ the last winding section having an inter
mediate tap connected to the anode of the last
of said tubes, the anode of a preceding tube be
ing connected to the negative side of said last
'gsection, and thezpositive sideof the latter be
It is thus seen that the arrangement "pro; ‘ ingiconnected- through a condenser to. the posi
vides for doing away with the usual use of sepa
20 rate choke coils at L1 and L2 or equivalent points
in the ?lter; avoids separate excitation of the
tive side of. the ?rst winding section.
I 2. In an amplifying and reproducing system, 20
a plurality of multi-electrode electron dischargevv
reproducer ?eld coils or the use of additional‘ tubes each thereof having input and output cir'-‘ '
?ltered current for these coils; saves the use cults, a'sound reproducer having a plural-section ‘
of a grid bias producing resistor for the output
25 tube; and saves the use'of va‘ potential reducing
?eld winding, rectifying means adapted to be
connected to a source of’ alternating current sup
resistor in the'?lter supply lead to the plate of ' ply for potentializing at least some of the» elec
tube AT1.
trodes of the electron discharge tubes, said plu
The general features of Fig.2 are substantially
those stated in detail as to Fig. 1. I have ‘not
shown the supplementing resistances R3 and R4
of Fig. 1 in? Fig. 2, it ‘being understood that
my invention contemplates in one form design
ing the resistances of the coils to by‘ themselves
7 produce the required differences: of potential for ‘'
grid biasing andv'plate potential reduction.
In Fig. 2 the ?eld winding of the reproducer
ral-section ?eld winding being conductively'con- __
nected to said rectifying means, and means con-"
necting an intermediate point of one section of 30
the plural-section ?eld winding to'oneof the.
electrodes of one of the electron discharge de
3. In. an amplifying andreproducing system,“
an output tube having an anode, a cathode and‘
a control electrode, an intermediate; tube having
is shown to include a." third section L3 which is
an anode, a cathode and a control electrode,v a .
shown so‘ connected that in addition toi‘the func- 1
reproducer having a ?eld winding, a rectifying->1
system having a pair of input terminals and a‘
'tions of 'producing‘a'?eld for" the reproducer,
40 ?ltering the‘ plate currents of both tubes AT].
and ATz and reducing plate potential, it func
tions as the choke for a choke and condenser
pair of output;terminals,~'said input terminals
being adapted to be connected to a source of al- 5
ternating current whereby there becomes avails l
output coupling for tube AT2, condenser C7 of»
able acrossv said output terminals uni-directional '
low impedance to audio frequency. signaling cur- '
pulsating current, one of said output terminalsv
being of positive potential ,with- respect to the’ 45:
other output terminals, a connection including
Irents serving as the capacityelement of the cou
With this coupling the‘direct current
component of the plate current of tube ATz is ' said ?eld winding’ between the said negative '
prevented from ?owing throughr'theiprimary of
output transformer T3,‘ thus avoiding. the di?i-'
50 culties of saturation‘ effects had with transfor
mers in the output circuit of power‘ ampli?er
It is. evident from the foregoing that my inven
tion provides for many economies‘and isimpli
55 .?cations in the elaborate. and complicated sys
terminal and the cathodes of said tubes, capaci
tive means connected between the positive termil :
nal and the negative terminal for smoothing the
uni-directional current, a connection including,
an 1nductance winding between the positive ter-'
minal of the source and the anode of said sec
ond named tube and aconductive connection be
tween the anode of the output tube and an inter;
tems which have beenbrought into use in con- ' mediate point of the last named winding.
nection' with completely energizing ampli?ers
4. An arrangement as described in the'ne'xt;
and electrodynamic reproducers from commercial preceding claim characterized by that the two
alternating current supply.
" .
windings are coupled with relation to each other
60 ' Having fully described my invention, I claim:
so that the ?elds resulting from the ?ow of cur
1. An amplifying and reproducing system in
rent therethrough are additive.
cluding a plurality of multi-electrode electron
discharge tubes having output circuits and a
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