Specifications
INSTRUCTIONS FOR ASSEMBLING DYNAKIT
MARK
IV
DESCRIPTION
The
Mark
IV
Amplifier uses a
circuit
arrangement
based
on
that
of
the
Dynakits
Mark
II
and
Mark
III
which
have
become world famous for
superior
quality
while essentially
simple
and
trouble
free.
The
new
7199
tube
is used
as
a
pentode
high
gain
voltage am-
plifier
directly
coupled
to
a
cathodyne
phase
inverter.
All
parameters
are
adjusted
for
minimum
distortion.
This
type
of
phase
inverter
has
the
unique
advantage
that
its
operation
is
independent
of
tube
aging so
that
no
adjustments
are
required
in
maintaining
optimum
performance.
An
internal
capacitive
feedback loop balances
the
phase
inverter
at
the
highest
frequencies,
and
the
arrangement
provides
accurately
balanced driving
signals to
the
output
tubes, which
are
EL-34's oper-
ated
well below
their
maximum
ratings.
The
output
tubes use a fixed. bias
arrangement
which is
set
through use
of
Dyna
Biaset
(patent
pending)
which
provides
optimum
linearity
of
the
tubes
and
mini-
mizes
the
effects of
unbalanced
components.
The
connection of
the
output
tubes includes a small per-
centage
of screen loading which improves
the
regu-
lation
of
the
output
stage
and
makes
it
comparatively
uncritical of load impedance.
The
impedance
match
and
bias conditions utilized
in
the
output
stage
provide
minimum
distortion
over
a very wide
dynamic
range.
In
addition,
20
DB
of
negative voltage feedback lowers
the
distortion
to
an
unmeasurable
proportion
at
normal listening levels
and
to
less
than
1%
intermodulation
distortion
at
40
watts
output.
The
use of a
minimum
number
of
phase
shifting
stages
along
with
careful
transformer
design makes
it
possible to
have
unconditional
stability
at
both
high
and
low frequencies.
This
feature of
the
design
means
that
there
is no
tendency
toward
motorboating
or
oscillation
under
any
condition
of use.
The
inherent
linearity
of
the
circuit, its
absolute
stability,
and
the
prefabrication
of all critical wiring
on
the
printed
circuit
assembly
make
construction
completely non-critical.
The
use of conservatively
operated,
highest
quality
components insures supe-
rior
and
dependable
operation
over a long period of
time.
GENERAL
WIRING
PRACTICE
Assembly of
the
Dynakit
Mark
IV
is
quite
simple
compared
to
general
kit
assembly requirements.
This
is because all
critical
parts
of
the
Dynakit
are
factory
assembled for
you
on
the
printed
circuit
assembly.
Other
parts
are
out
in
the
open
in a free
and
unclut-
tered
layout
so
there
is easy accessibility for wiring
or
trouble shooting purposes. Con<;truction of
your
Dynakit
should
not
take
more
than
three hours be-
cause
of
these
simplifications.
Upon
opening
your
kit, check
the
components
with
the
parts
list.
Familiarize
yourself with
the
compo-
nents;
they
can
be identified by
comparison
with
the
pictorial
diagram
and
by
specified color coding.
Tools required for easy assembly
of
your
Dynaldt
are
a soldering
iron
(small
tip)
or
soldering gun,
long nose pliers, screwdriver,
and
wire
cutters. Al-
though
not
essential, a low
cost
wire
stripper
and
cutter
of
the
type
which
can
be
purchased
for less
than
a
dollar
win
greatly
facilitate
cutting
and
strip-
ping
the
various leads
in
the
kit.
c,;ood
soldering technique is
valuable
in
obtaining
satIsfactory results from
any
electronic equipment.
ALL
SOLDERING
MUST
BE
DONE
WITH
ROSIN
CORE
SOLDER.
There
is
no
warranty
on
any
equipment
in
which
acid
core solder has been
used.
Make
sure
that
the
solder
is
plainly
marked
"Rosin
Core."
If
you
have
solder
on
hand
the
origin
of which is doubtful,
it
is wise
to
obtain
new
50/50
or
60/40
rosin core solder.
Whenever
soldering is
required,
the
assembly
instructions
specify
it
by
"(S)
".
If
this symbol is
not
shown
after
a connection
is specified,
it
indicates
that
further
connections will
be
made
at
that
point
before soldering.
Soldering is accomplished
by
heating
the
joint
with
the
iron
until solder is
hot
enough to
flow
when
touched to
the
joint.
It
is
not
desirable
to
feed
the
solder
to
the
iron.
It
should
be fed
to
the
junction
of
iron
and
joint. After
the
solder
flows,
the
iron
should
be held in place for a few seconds
and
removed when
it
is seen
that
the
solder
has
contacted
both
parts
of
the
connection-the
lug
and
the
wire connected
to
it.
It
should
not
show a ball
of
solder,
hut
a smooth
transition
from solder to
component
lead.
Before
applying
solder
the
joint
should
be
c1e.an
and
the lead
should
be
crimped in
place
so
as
to have
mechanical security.
It
is
not
necessary to
wrap
leads
around
contacts
many
times. A single
turn
and
pinch-
ing together
with
pliers is suitable. After soldering
there should be no
play
at
the
joint
if the )Pad is
wiggled
with
a
pair
of pliers.
It
is practical to
do
all
soldering
with
a pencil
type
iron
wi~h
a low
wattage
:ating.
A small
tip
is
extremely useful when working
III
confined space.
If
a soldering gun
is
used
it
should
be used with discretion since
the
amount
of
heat
available
is
far more
than
required
fOl'
soldering
light
wires.
Component
leads
should
be trimmed as
they
are
used;
the
length should be
such
that
the
proper
con-
nection
can
be
made
from
point
to
point
without
strain
on lugs or components.
Care
should
be exer·
cised
not
to allow wires to touch
one
another
unless
they
are
actually
connectf::.j to the
same
point.
The
instructions which follow have been
arranged
for simplified procedure in which
the
work can be
done
without
interference between
the
various por-
tions of
the
wiring.
It
is recommended
that
the in-
structions
be followed
on
a
step
by
step
basis, check-
ing off each
step
as
it
is completed.
The
pictorial
diagrams
should be used for reference
and
all con-
nections Checked
against
these before going on to
tlw
next step.
If
the wiring is done methodically
and
each
step
checked carefully,
your
amplifier
should
work
without
difficulty
as
soon
as
it
is completed.