Heathkit SB-201 - Page 5

Page 4
Ge QuEeatrHKIT:
INTRODUCTION
The Heathkit Model SB-201 Linear Amplifier is a
completely self-contained, grounded-grid, table top
amplifier for use on the 80, 40, 20 and 15 meter
amateur bands. The Amplifier is rated at a power
input of 1200 watts peak envelope power (P.E.P.) for
voice operation on SSB, and at 1000 watts on CW.
The Amplifier is designed to be used with exciters
which deliver 100 watts output. It can be used with
lower driving power, but its output power will be
less.
A
broad-band,
tuned
input
circuit
for
each
band
feeds
the
two
572-B
(or
two
T-160-L)
triode
tubes
connected
in
grounded
grid
configuration.
The
tubes
are
cooled
by
a
fan
to
prolong
tube
life.
An ALC circuit develops negative voltage to be fed
back to the exciter to reduce its gain when the
Amplifier is overdriven.
The antenna change-over relay is normally actuated
by exciter relay contacts to switch the Amplifier to the
transmit mode.
The Amplifier can be operated from either 120 VAC or
240 VAC 50/60 Hz lines and can be easily changed
from one to the other. Operation from a 240 volt line is
recommended, but not required. Each side of the line
cord is equipped with a circuit breaker to protect
against overloads.
CONSTRUCTION NOTES
This manual is supplied to assist you in every way to
complete your kit with the least possible chance for
error. The arrangement shown is the result of exten-
sive experimentation and trial. If followed carefully,
the result will be highly stable and dependable per-
formance. We suggest that you retain the manual in
your files for future reference, both in the use of the
equipment and for its maintenance.
UNPACK THE KIT CAREFULLY AND CHECK EACH
PART AGAINST THE PARTS LIST. In so doing, you
will become acquainted with the parts. If some short-
age or parts damage is found in checking the Parts
List, please read the Replacements section and supply
the information called for therein.
Resistors generally have a tolerance rating of 10%
unless otherwise stated in the Parts List. Tolerances
on capacitors are generally even greater. Limits of
+100% and -20% are common for electrolytic
capacitors.
We suggest that you do the following before work is
started:
1. Lay out all parts so that they are readily availa-
ble.
2. Provide yourself with good quality tools. Basic
tool requirements consist of a screwdriver with
a 1/4” blade; a small screwdriver with a 1/8”
blade; phillips screwdriver; long-nose pliers;
wire cutters, preferably separate diagonal cut-
ters; a penknife or a tool for stripping insulation
from wires; a soldering iron (or gun) and rosin
core solder. A set of nut drivers and a nut starter,
while not necessary, will aid extensively in con-
struction of the kit.
Most kit builders find it helpful to separate the vari-
ous parts into convenient categories. Muffin tins or
molded egg cartons make convenient trays for smal]
parts. Resistors and capacitors may be placed with
their lead ends inserted in the edge of a piece of
corrugated cardboard until they are needed. Values
can be written on the cardboard next to each compo-
nent. The illustration shows one method that may be
used.