Heathkit W-5M User Manual

A
load
limiting
device
is
built
into the
amplifier
to
provide
high
frequency
and
transient
stability.
Rising
impedance
effects
of
speaker
systems at
higher
frequencies
will
frequently cause
oscill-
ation
in a
feedback
type
amplifier,
since
the
amplifier
fails
to see a
reasonable
load at
these
frequencies.
To
counteract
this,
a
resistor
and
condenser
have
been
installed
in series
across
the
output
transformer
secondary.
The
condenser
is
chosen
to prevent the
loading of the amp-
lifier
throughtout
the
audible
portion of the
spectrum and
still
provide suitable
loading above
these
frequencies;
thus
assuring
complete
stability
under
all dynamic
operating
conditions.
Power
for the
amplifier is supplied by a
husky
power
transformer
and a
high
current
ruggedized
5R4GY
rectifier. Output from
the
5R4GY
is
very
well
filtered
in
an
inductance-resistance-
capacity
filter
to keep
noise and
low
frequency
instability
at a
minimum.
High
capacity
filter
sections
are used
throughout
to
reduce
power
supply
impedance
at
low audio
frequencies.
Well
regulated
high voltage
at
high
current
is
available
for the
output
stage,
allowing
high
power
out-
put
at
very
low distortion.
Only
the
highest possible
quality
components
have
been
incorporated
in
the
Heathkit
model
W-5M
Amplifier. At
no point
have
corners
been
cut
to reduce
cost
at the
expense
of quality
parts or
performance. All
components
are
conservatively
rated,
giving
assurance
of
trouble-free
perfor-
mance
for a long time.
An
example
of the
conservative
rating
of parts
is
the
5R4GY
rectifier
.
Another type
of
rectifier
was
considered
and
was
actually
used
in the
original
development
model.
While
this
tube
was
adequate
for the
purpose,
it was
operating
near
maximum
ratings
and so
the
decision was made
to use
the
more
expensive
and
rugged
5R4GY
instead.
A
high
safety
factor
is used
in
the
filter
section
of the power
supply
also. The
electrolytic
filter
condensers
are
con-
nected
in
series
with
voltage
balancing resistors
across them,
providing a
maximum
voltage
rating of
900 volts
at
the
first two sections
of
the filter, where
the
operating
voltage is
in
the
neighborhood of
500
volts
and
700
volts
at the output
section,
where
the
operating voltage
is
470
volts. Special
single
section
condensers
could have been
used,
but
it would be
impossible
to
employ them
and
provide the
safety
factor
obtained
by
using series
units.
The
amplifier cover
is
another advantage,
in that
the appearance is
improved
and small
children
are protected
from
severe burns since
they cannot touch
the output
tubes
and rectifier,
which
run quite hot.
NOTES
ON
ASSEMBLY
AND
WIRING
Your
Heathkit
Amplifier,
model
W-5M
represents
a
substantial
outlay of
money. In
order to
get
the high
performance
return for your
investment
it is extremely
important
that you
take the time
to read
the
manual
carefully
before
construction is
started.
Carefully read
each
step
all of
the
way
through
until it
is
completely
understood.
After you
are
thoroughly
familiar with the
pro-
cedure
used,
construction
of the kit
can
be
started. Care
exercised
in
construction will
be
re-
warded
with
a greater
sense
of
confidence,
both
in
your
amplifier and
your
own ability.
This
manual is
supplied to
assist
you in every way
to
complete
the
instrument
with the least pos-
sible
chance
for error. The
detailed
instructions
are
specifically
written to
allow either the ex-
perienced
or
inexperienced
constructor to
construct
the unit with a
minimum
of
difficulty.
Only
a
very
small
percentage
of Heathkit
assemblers
encounter any
difficulty
whatsoever
in complet-
ing
kits
of this
kind.
Large
fold-in pictorial
diagrams are
included
in the
manual for your
con-
venience
and
are quite
helpful if attached
to the
wall above
your
work
space. The
diagrams
are
repeated
in
smaller
form
within the
manual
proper.
We
suggest
that you
retain the
manual
in
your
files
for
future reference in
the use
of the
amplifier
and its
maintenance.
UNPACK
THE
KIT CAREFULLY AND
CHECK EACH
PART
AGAINST
THE
PARTS LIST.
DO
NOT
DISCARD
ANY
PACKING
MATERIAL
UNTIL THIS
HAS BEEN
DONE.
In so
doing,
you
will
become
acquainted
with each
part
and the
chance
of
accidentally
throwing away
some
part
will
be
eliminated.
Full
size sketches
of each
of the
parts
categories
appear
on
Page
32.
Use
this
in
checking
against
the
parts
list
and in
identifying
any
questionable
components.
Components
with
wire
pigtail
leads can
be
conveniently sorted
by
inserting
one of the
leads
into
the corrugated
edge
of
the shipping carton flap.
It
may be
helpful to
mark
the
value of
the com-
ponent on the
flap
so
the
part
may
be
readily
located when
needed.
Page
11

Heathkit W-5M Specifications

General

Brand	Heathkit
Model	W-5M
Category	Amplifier
Language	English