Belt Valley times. [volume] (Armington, Mont.) 1894-1977, 1925-11-19

OF resistance-c0upled ampiincati0n- BE
fore going. let It be said that the
resistance-coupled application en-
pIoyed should not be confused with
similar systems described In the past
because It Is now possible to maintain
tone quality, for which this type OF
amplifer Is famous, together with
great volume, due to the fOresighted-
ness OF some OF the tube manufactur-
ers who are now marketing what are
known as high-Mu tubes. These tubes
are specially designed for resistance
coupled ampIificatlon and the ampli-
hcation per stage which is obtalnable
with them is far greater than has
heretofore been generally possible.
"As was mentioned above. tuning Is
accomplished by a single dial. This
dial Is used to control a Hanscom
singIe-control unit and is the main
tuning control. II Is unique arrange
ment Of two Remler condensers. geared
together In q manner which makes
tuning Of the antenna and radiO-fre-
Quency circuits simultaneous. The.
panel Is 7 by IS inches and there Is
plenty of room on 1t for all the equip
ment necessary, when q sub-base is
employed.
1.-The tuning inductances and the
variable condenser assembly. antenna
switch and battery switch are mounted
on the main panel, while all the re-
naming equipment Is either on the
top or bottom OF 8 pa by 17s-inch
subpanel. which Is suspended from the
main panel by means Of Benjamin No.
600 brackets. On the upper side OF
the subpanel are mounted the flve tube
sockets. three reslsto-c0uplers, the grid
condenser and leak mounting, and the
variable neutralizing condenser. It Is
also possible TO nnd room for all the |
binding posts. including those for the
three connections for the @ battery, II
they are thought to be desirable. On !
the under side Of the subpanel there I
are five mountings which are used for
the filament ballast resistors. All these
points are clarified by the Illustrations
Of the original article In Radio Broad
cast Magazine.
Lists Of Parts.
The list Of parts used is as follows:
One by Is panel.
One 2h by tn subpanel.
One Hanscom s. G. condenser unit.
One set Eastern knockout coils
One Carter filament switch.
Two Apex knobs.
Five BENJAMIN sockets.
Three Daven reststO-cOupiers with
three i megohm resistors and one
each meg. 3 meg, and rs meg. re
sisters.
One Hammarlund neutralizIng con-
ienser.
Two 004 Sangamo fixed condensers.
One Dubilier 8 mlcrofarad bypass
Six Daven No. so mountings.
One Daven ieakandenser "a new
init which combines the grid con-
ienser and leak).
Five Daven ballast resistors 1.-THE
.apactty Of these resisters depends on
he type of the tubes usedl.
One BeIden standard color. Eve wire
able.
Two Benjamin No. 600 brackets
Two to six Eby binding posts
Two dozen or $50 round head.
rass machine screws. y inch long.
About six 2-fOot lengths Of bus bar.
~The Eve ballast resistors are shown {
a the diagram as R1-2-S-4-5 The Sc
sctIon Of these will depend entirely
n the types OF tubes employed. The
deal combination Of tubes consists In !
be use Of two ordinary six-volt stor~ {
sc battery tubes for thu, radlo-fre-
uency ampllGer and the detecfor. two
igh-Mu tubes for the first two stages :
audio. with q semipower tube In the
lrst Stage Some tubes Win work
without any resistance IN !
be filament circuit when used as am
liHers." a