Fairchild CONAX 600 User manual

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INSTRUCTION
MANUAL
MODEL
602
CONAX
(Conaccelerator)
Dual Channel
Operation
U.S.
Patent
No
3
111
.
635
FAIRCHILD
RECORDING
EQUIPMENT
CORPORATION
10-40
45th
Avenue, Long
Island
City,
NY.
IB602

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GENERAL
FAIRCHILD
CONAX
MODEL
602
The
FAIRCHILD
CONAX
is
a
device
primarily
developed
for
disk
recording.
It
reduces
the
excessive
accelerations
which
oc-
cur
at
high
frequencies.
Present
day
microphone
technique
and
orchestration,
combined
with
the
RIAA
treble
pre-emphasis,
often
cream
quite
impossible
levels
at
the
highest
audible
frequencies.
Until
the
last
few
years,
it
was
assumed
that
the
peak
energy
content
in
music
and
other
recorded
sounds
decreased
with
in-
creasing
frequency,
so
this
apparent
margin
was
utilized
to
increase
the
signal-to-noise
ratio
by
emphasizing
the
high
frequencies
in
the
sending
(recording)
end,
and
de-emphasiz-
ing
them
at
the
receiving
(reproducing)
end.
By
so
doing,
a
considerable
reduction
in
hiss
and
record
noise
was
obtained.
"Listener's
fatigue"
was
reduced
and
the
overall
quality
was
considerably
improved.
This
was
done
in
FM
and
TV
broadcasting
as
well
as
in
disk
recording
with
equally
good
results.
The
improved
frequency
response
of
presently
used
microphones,
and
the
character
of
the
transmitted
(recorded)
material
is
sometimes
a
problem
however,
as
mentioned
above.
Live
TV
shows,
like
children's
programs,
where
numerous
percussion-
life
noises
may
produce
transients
with
excessive
high
fre-
quency
amplitudes
can
easily
over-modulate
the
transmitter,
if
the
level
is
not
brought
down,
or
a
radical
filter
inserted.
The
CONAX
is
ideal
for
putting
a
ceiling
on
the
high
frequency
peaks.
Tape
recording
is
another
field
where
the
CONAX
could
be
used
to
advantage,
as
tape
recording
curves
also
contain
treble
pre-emphasis.
The
tape
itself
already
has
a
limiting
action
(saturation)
at
high
frequencies,
but
unless
the
recording
amplifier
is
free
of
distortion
up
to
levels
15
to
20
db
above
tape
saturation
at
these
frequencies,
the
amplifier
distortion
will
be
the
limitation.
The
CONAX
will,
however,
solve
the
overload
problem
with
a minimum
of
audible
change
in
soundc
Lower
tape
speeds,
particularly,
with
considerable
treble
pre-emphasis
can
take
advantage
of
a
CONAX.
Tape
duplication
is
another
field
where
the
CONAX
would
be
highly
effective,
especially
where
the
material
is
transferred
to
lower
speed
tape.
In
original
recording
sessions,
CONAX,
inserted
in
a
micro-
phone
channel
and
used
with
discretion,
will
take
oaro
of
ex-
cessive
nighs
produced
by
female
sibilant.
singers,
loud
cymbals,
muted
trumpets,
bells,
onst
.
cuiets
and
similar
sounds,
and
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•
Model
602
CONAX
still
maintain
the
basic
sound
quality.
The
design
of
the
CONAX
is
a
result
of
both
theoretical
and
practical
studies.
Even
though
it
is
impossible
to
insert
a
filter
with
considerable
filtering
action
in
an
audio
circuit
without
noticeable
change
in
sound,
the
CONAX
is
very
close
to
this
seemingly
impossible
action
and
requirement.
The
reason
for
this
is
that
the
ear
is
not
very
sensitive
to
level
differences
at
the
highest
frequencies,
so
a
considerable
reduction
is
possible
without
audible
change
if
the
duration
of
the
high
level
peaks
is
short,
that
is,
if
it
does
net
amount
to
a
major
part
of
the
total
energy
content
of
the
music.
If
there
is
a
continuous
high
level
at
the
highest
frequencies,
the
action
of
course
will
be
audible
and
the
unit
will
act
as
a
filter.
The
CONAX
will
always
ensure
the
necessary
safety
margin
and
permit
higher
apparent
levels
on
records,
tapes
and
pre-
emphasized
broadcasting.
DESCRIPTION
The
MODEL
600
CONAX
is
a
single
channel
unit.
The
MODEL
602
is
a
dual
channel
unit
for
stereo
use.
As
both
chan-
nels
in
the
stereo
CONAX
are
similar,
only
one
will
be
de-
scribed
here.
Inputs
and
outputs
appear
on
barrier-type
terminals
at
the
rear
of
the
unit.
Plus
4
VU
signal
is
fed
to
an
input
trans-
former.
From
the
secondary,
the
signal
is
fed
to
the
complex
automatic
filer,
FL-101.
The
output
of
the
filter
feeds
the
grid
of
1/2
12AX7
which,
in
turn,
feeds
the
transformer
loaded
output
tube
1/2
12BH7A.
Feedback
is
applied
from
the
primary
of
the
output
transformer
to
the
cathode
of
1/2
12AX7
without
frequency
discrimination.
Amplifier
gain
is
variable
by
varying
the
amount
of
feedback.
Screwdriver
controls
Rl09
and
R209
are
accessible
through
the
front
panel
for
this
purpose.
In
addition
to
plate
and
filament
voltage,
the
power
supply
also
furnishes
a
DC
regulating
voltage
for
the
filter.
The
threshold
is
variable
in
6
steps.
In
OFF
position,
the
amplifier
works
as
a
straight
unity
gain
line
amplifier
with
the
filter
inactive.
In
the
other
positions,
different
amounts
of
CONAX
action
takes
place,
the
action
increasing
as
position
numbers
increase.
INSTALLATION
&
OPERATION
Unpack
the
unit.
Remove
the
gray
front
cover
plate,
mount
the
unit
in
a
relay
rack,
and
mount
the
gray
cover
plate
in
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Model
602
CONAX
front
of
the
black
front
panel.
Connect
to
the
program
buss
as
described
in
INPUT
&
OUTPUT
CONNECTIONS.
The
unit
is
adjusted
to
unity
gain
at
the
factory.
If
tubes
are
replaced
or
the
GAIN
controls
have
been
touched,
the
adjustment
procedure
is
as
follows:
Set
the
threshold
control
to
OFF,
feed
lKC
at
-+4
dbm
into
the
unit.
Adjust
the
gain
control(s)
in
the
front
panel
until
+4
dbm
appears
at
the
output
(terminated).
OPERATION
With
the
THRESHOLD
switch
in
OFF
position,
the
CONAX
is
a
unit
gain
amplifier.
With
the
THRESHOLD
switch
in
Position
1,
only
the
highest
frequencies,
10
to
15KC,
are
affected.
As
the
THRESHOLD
switch
is
advanced
towards
larger
position
numbers,
the
8
ction
becomes
more
effective
at
higher
fre-
...
iencies.
·
As
program
material
varies
greatly
in
high
frequency
content
and
duration
of
high
frequency
peak
levels,
the
application
of
the
CONAX
is
somewhat a
question
of
cut
and
try,
if
a
peak
reading
meter
with
sufficiently
short
attack
time
to
catvh
10
to
15KC
peaks
is
not
at
hand.
The
FAIRCHILD
MODEL
641
stereo
cutting
system
contains
such
a
meter.
On
this
meter,
the
action
of
the
CONAX
can
be
read
directly
in
db
if
a
given
musical
selection
is
ylayed
with
and
without
the
CONAX.
The
CONAX
should
be
used
with
discretion,
that
is,
should
not
always
work
in
position
5
which
will
give
a maximum
filtering
action,
and
under
extreme
conditions
slight
intermodulation
distortion.
If
this
happens,
retard
the
THREffiOLD
switch
to
a
lower
number.
As
the
design
is
centered
on maximum
action
with
minimum
audibility
for
a
majority
of
pleak
energy
distribution
curves,
careful
use
of
this
unit
woll
make
possible
recordings
and
transmissions
of
optimum
quality,
with
the
advantages
of
re-
ducing
hiss
and
record
noise
and
high
level
operation
simultaneously,,
INPUT
&
OUTPUT
CONNECTIONS
Inputs
and
outputs
appear
at
the
rear
of
the
unit
on
barrier-
type
terminal
strips.
It
is
recommended
that
the
CONAX
be
connected
between
an
eventual
limiter
and
the
cutting
amplifier
in
disk
recordingo
-3-
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•
Model 602 CONAX
LEFT CHANNEL - INPUT
(Z= 600 ohms)
Terminal 1 - tiepoint (no internal
connection)
Terminal 2 - high
Terminal 3 - low
Terminal 4 - ground (chassis)
RIGHT CHANNEL - INPUT
(Z= 600 ohms)
Terminal 5 tie point (no internal
connection)
Terminal 6 ·- high
Terminal 7· - low
NOTE: If a floating circuit is used, it is
necessary that Terminals 3 and 7 be strapped
to Terminal 4.
LEFT CHANNEL - OUTPUT
(Z= 600 ohms)
Terminal
8 -
high
Terminal
9 -
low
Terminal 10 - ground
(chassis)
RIGHT CHANNEL - OUTPUT
(Z= 600 ohms)
Terminal
11
- high
..
Terminal
12 -
low
NOTE: If a flating circuit is used, it is
necessary that Terminals 9 and 12 be strapped
to Terminal 10 •
If 150 oho · output impedances are deeired, . open front of the · coNAX
and restrap the output transformers inside the chassis. The
connections are as follows:
150 ohms: join 5 and 6, connectto 4 and 7
600 ohms: join 5 and 6, connect to 3 and 8
If 150 ohm input impedances are desired, open front of the CONAX
and restrap the input transformers. The connections are as
follows:
150 ohms: disconnect wire between 2 and 3. Join 1 and
2. Join 3 and 4, connect to 1 and 4. Replace
820 ohm resistor with a 220 ohm.
(cont'd)
-4-

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Model 602 CONAX
600 Ohms: Join 2 and 3, connect to 1 and 4
Connect 820 ohm resistor from 1 to 4.
1'1.AINTENANCE
Very little maintenance is necessary. To check whether the
CONAX actioh is effective, feed +14dbm at 1 kc and 10 kc into
the unit with the THRESHOLD control in position 5. The dif-
ference in level shall be app~oximately 15 db.
SPECIFICATIONS
GAIN
INPUT LEVEL REQUIREMENT
OUTPUT LEVEL
INPUT IMPEDANCE
OUTPUT IMPEDANCE
FREQUENCY RESPONSE
DISTORTION
NOISE
SEPARATION
TUBE COMPLEMENT
FUSE
PO'W.ER REQUIREMENTS
WEIGHT
MECHANICAL DIMENSIONS
WARRANTY
1
+4 VU or +8 VU
+4 VU or +8 VU (no overload
before .e.7 dbm)
150 ohm/600 ohm
150 ohm/600 ohm
As straight amplifier: +l db
25 cps to 15 KC
Maximum filter action: 6 db/octave.
Roll off from 2 kc (75 micro-
seconds)
Below filter threshold: less than
1%
70 db below +4 dbm
Better than 45 db
1 - 6X4
1 - 12AX 7 or ECC83
1 - 12BH7
1 amp
117V AC 30 VA (600) 35 VA (602)
16.5 lbs
Standard 19" rack. 51/4" rack
space, depth behind panel 91/2"
Every FAIRCHILD professional product carries a 90 day warranty
on all parts. Should any part be found defective, the entire
-5-

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•
Model 602
CONAX
unit
may
be
returned
to
the
factory
during
the
warranty
period
for
service,
or,
if
applicable,
FAIRCHILD
will
supply
the
re-
placement
part
to
you
if
you
wish
to
ihstall
yourself.
I
To
validate
the
warranty
4
please
complete
and
return
the
wqrranty
registration
included
in
this
manual.
If
there
is
any
question
vn
this
or
other
FAIRCHILD
professional
products,
please
do
not
hesitate
to
contact
us.
ATTACHMENTS
Schematic
diagram
-
CONAX
MODEL
602
CONAX-action
curves
WARRANTY
REGISTRATION
MODEL
602
CONAX
Serial
No.
Name
of
Purchaser
--------------------------
Date
Address
of
Purchaser
Purchase
&
Name
of
Distributor
Address
of
Distributor
( ) Check
here
if
you
desire
to
be
placed
on
regular
ruai~ins
list~
COMPLETE
&
RETURN
TO:
FAIRCHILD
RECORDING
EQUIPMENT
CORPOhNtION
10-40
45th
Ave.,
Long
Island
City
1,
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OUTPUT
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\ II
DOTTED
LINE:
INPUT
SIGNAL
\ II
\
11
\ II
\
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