Russco Fidelity-pro User manual

STEAM POWERED RADIO.COM
FIDELITY
-
PRO
FIDELITY
-
MASTER
MONO
&
STEREO
PHONO
PREAMPLIFIERS

STEAM POWERED RADIO.COM
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FIDELITY-PRO
FIDELITY-MASTER
MONO & STEREO PHONO PREAMPLIFIERS
WARRANTY
All Russco products are warranted against defects in
workmanship and materials for a period of one year
from
the date of delivery. We will repair or replace
products which prove
to be defective during the
warranty period provided they are returned to Russco.
Warranty subject
to cancellation if in the opinion of
Ru ssco the product has been either unduly tampered
with or modified so as
to cause failure bey.ond our
control. No other warranty
is expressed or implied.
We are not liable for consequential damages.
''
RUSSCO ELECTRONICS M. FG., INC.
5690 E. Shields
Fresno, Calif. 93727
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STEAM POWERED RADIO.COM
RUSSCO
FIDELITY-MASTER
AND
FIDELITY-PRO
PHONO
PREAMPLIFIERS
DESCRIPTION:
The
Russco
Fidelity-Pro
and
Fidelity-Master phono preamplifiers
are
professional quality,
RIAA
equalized phono playback preamplifiers designed specifically
for
use
in broadcast
and
recording
studios.
All
models feature a self-contained power supply, integrated circuits and a single piece
extruded aluminum
case
designed
for
easy
serviceability. The Fidelity-Pro model offers low
and
high frequency filters
not
available on the Fidelity-Master.
All
models
are
available in either stereo
or
mono versions
with
unbalanced
or
balanced (transformer) output. A special feature
of
all models
is
the
use
of
two
integrated circuits
for
each
channel: a
low
noise preamp
unit
coupled
to
a high
slew-rate
output
unit. This allows
output
levels
to
+18dBm
into
a 600 ohm line over the
full
audio
spectrum.
The following table
is
provided
as
aquick reference
to
illustrate the features
of
the different models:
FIDELITY
-MASTER MODELS
FIDELITY
-
PRO
MODELS
MODEL
FMMU
FMMB
FMSU
FMSB
FPMU FPMB
FPSU
FPSB
,v1ONO
X X X X
STEREO X X X X
FIXED
EQUALIZATION
X X X X
RUMBLE
FILTER
SWITCH X
X
X X
H.
F.
BOOST
&
CUT SWITCH X X X X
UNBALANCED
OUTPUT X X X
X
BALANCED
OUTPUT X X X ' X
PART NUMBER
~018
900-019 900-016 900-017
~014
900-015 900-012 900-013
-1-

STEAM POWERED RADIO.COM
RUSSCO
FIDELITY-MASTER
AND
FIDELITY-PRO
PHONO
PREAMPLIFIERS
SPECIFICATIONS: (All Models Except
as
Noted)
Frequency
Response:
20
to
15,000 Hz, ±
1 dB
of
R
IAA
Curve. (Transformer models down
approximately 3 dB at 15 KHz
with
600 ohms load, flat with no load.)
Noise: Equivalent
to
-108 dBm input at I KHz. (70 dB below NAB standard reference
level
using
Shure M44-7 cartridge.)
Distortion:
Less
than 0.1% THO at +18 dBm
out
into
600 ohms, 20
to
15,000
Hz
. (Transformer
models
less
than
0.1%
at +17.5 dBm
out
into
600 ohms, 30
to
15,000
Hz,
20 Hz
less
than 0.1% THO at +10 dBm out,
less
than
1%
at +17.5 dBm out.)
Maximum Output Level: +18 dBm
into
600 ohms, +22 dBm no load.
Maximum
Input
Level: 100 millivolts
RMS
at 1KHz.
Input Sensitivity: 1
millivolt
RMS
at 1KHz
for
O
dBm output.
Crosstalk (Stereo Models Only): Greater than 55 dB down at 15KHz; greater than 65 dB down at
1KHz.
Input Impedance:
47,000
ohms.
Output Impedance: 600 ohms
for
transformer models,
less
than 10 ohms
for
unbalanced models.
Filters (Fidelity-Pro models):
'\
4
I
Low Frequency: Flat
Cut: -3 dB at 70 Hz,
-8
dB at 30
Hz.
I
High Frequency: Boost: +3 dB at 5KHz, +5 dB at 10 KHz,
level
from 10KHz up.
Flat·
Cut:
-3
dB at 4.5KHz,
-6
dB at 7KHz, rolls
off
at 6 dB per octave
above
7KHz.
Power: 117 Volts
AC,
60 Hz, 40 milliwatts.
Size:
11"
long x 4-3/4" wide x 1-3/4" high (including hardware).
Shipping weight: 4 pounds maximum, depending on model.
Operating weight: 2
to
3 pounds, depending on model.
NOTE:
All
specifications
based
on tests
made
with tone-arm
and
Shure M44-7 cartridge hooked
up
to
the preamp.
Signal
driven through cartridge
across
a 100 ohm resistor on the ground
side
of
the cartridge.
-2-

STEAM POWERED RADIO.COM
UNPACKING AND INSTALLATION
UNPACKING:
Remove the styrofoam packers from both sides of the preamp case. No other packing material need
be removed.
INSTALLATION:
The preamp may be set free standing on a shelf or may be mounted to any flat surface. Holes for
number six screws are provided
in the base flange. It can be mounted to wood or metal, but care
should be taken regarding grounding if mounted
to metal. (The case is at ground potential.)
When locating the preamp, avoid areas near electric motors or transformers where strong fields may
be present.
Ventilation
is not a critical factor due to the low power dissipation of the unit, but areas of high
ambient temperature (over 120 degrees fahrenheit) should be avoided
to assure long component
life.
CONNECTIONS:
INPUT: Plug leads from tone-arm into input jack(s) on front panel. Use standard RCA phono
type
pl ugs . Connect tonr -arm ground lead under the ground post screw.
OU TPUT: Connect output leads to the terminal st1 ip on the rear panel.
For unbalanced models use single
or two conductor shielded line, connecting grounds at the
terminals marked" -" or "GND". Connect center or hot lead to the terminals marked"+". These
models need
not be terminated in any particular toad, but if termi; --a ted, the load should be no less
than 600 ohms. If two conductor shielded line is used, the shield should he grounded at one end
only.
Balanced models may
be connected with two conductor twisted line, shielded or unshielded. Connect
wires to terminals marked"+" and"-". The shield can be connected to the terminal marked "GND",
but should be connected at one end only. Balanced models may be terminated with a 600 ohm re-
sistor or transformer. An increase in high frequency response will result if the output is terminated
in a high impedance. For long line applications and installations in an environment of noisy fields, it
is recommended that the output transformer center-taps be grounded. See special instructions on
page six for this modification.
POWER : Insert power cord into any standard 117 VAC, 60 Hz outlet. There is no power switch
on
the preamp and it may be left connected to the power indefinitely as it draws so little power.
- 3-
..

STEAM POWERED RADIO.COM
If
it
is
desired
to
disconnect
the
AC
power during non-operative periods,
the
preamp may be
connected
to
a switched
AC
outlet.
CHECK OUT AND CALIBRATION:
Playing any reference signal recording (such as
the
NAB
Test Record
Level
Check Signal) adjust
level controls for
the
desired
output
level. The level controls are accessible through holes
in
the
front panel.
Use
a small slot
type
screwdriver.
NOTE:
When using an
AC
powered meter
to
measure
the
output
level of balanced
output
models, take care
that
both
sides
of
the
measured line are kept above ground. Grounding
one side
of
the
line may cause false readings. Frequency response tests made using a disc
recording as
the
signal source will display
the
frequency response characteristics
of
the
cartridge as well as those
of
the
preamp. Response may
be
modified
on
Fidelity-Pro models
by changing
the
high and low frequency switch positions. Balanced
output
models can have
the
high frequency response raised
by
increasing
the
output
load impedance
to
some value
above
600
ohms.
IN
CASE
OF
DIFFICULTY:
The following preliminary steps are recommended as a prelude
to
actually trouble shooting
the
preamp itself.
If
these steps prove insufficient in solving
the
problem,
the
preamp should
be
returned
to
the
factory for repair
or
serviced
by
a qualified technical person. See "Servicing
the
Preamp"
on
pages five
and
six for technical guidelines..··
~
A.
Preamp does
not
appear
to
operate. . .
•
,!
1. Check all
exte
rn
al
connection~.for shorts, broken wires or loose connections.
2.
Check
tone
-arm and ca,rt;ridge connections.
3. Check power cord c
,er
mection. ls-the
AC
to
the
outlet
turned
onf
4. Check fuse and replace if blown.
A
B.
High Noise
or
Hum.
1.
Check all
gr
ound connections
to
be sure
that
they
are tight.
2.
Move
the
pr
eamp
away
from any field producing objects, such as motors,
AC
lines
or
transformer
s.
3.
Turn
the
AC
plug over.
4. Try various combinations
of
grounding
to
the
turntable,
tone
-arm, preamp chassis and
preamp ground terminals.
5. Some tone-arms
that
have a common ground shielded lead cable can cause ground-loop
problems. It may help
to
disconnect one
of
the
grounds
at
either
the
cartridge
or
preamp end
of
the
cable. (This generally applies
to
stereo installations only.)
-
4-

STEAM POWERED RADIO.COM
C.
Distortion.
1.
Make sure
that
there are no partial shorts on
the
output
lines.
2. Make sure
that
the
load
on
the
output
lines
is
no
less
than
600
ohms.
If
the
load
is
less
than
600
ohms, a series resistor should be
put
in
the
line
to
bring
the
preamp
output
load up
to
600 ohms. The preamp
level
is
then turned up
to
overcome
the
loss due
to
the
series resistor.
SERVICING
THE
PREAMP
DISASSEMBLY:
See figure one, page nine. Remove
the
two
phillips head screws
on
the
front panel. Grasp
the
panel
on
both
sides with fingers resting in
the
finger reliefs and pull
the
panel straight forward,
removing
the
circuit board from
the
box. Slide
the
top
panel
out
of
the
box. The P.C. board
can now be replaced
in
the
box
for operational testing.
If
desired,
the
rear panel can
be
removed from
the
box
in
a similar manner. The P.
C.
board can
then
be plugged back into
the
ro
cket and
tne
entire unit can be operated outside
of
the
box.
TESTING:
The use
of
only high impedance
AC
and
DC
meters
is
rr
.;
ommended for testing
the
circuitry
of
the
preamp.
The first
test
performed on a non-operational unit should be for
~
•
.>
per
DC
voltages. NOTE THAT
THE CIRCUIT USES BOTH POSITIVE AND NEGATIVE
DC
VOLTAGES. METER POLARITY
WILL HAVE TO
BE
CHANGED
WHEN
MOVING THE TEST PROBE FRO.
II
POSITIVE
DC
TO
NEGATIVE
DC.
All
measurements are made with reference
to
ground.
After it has been confirmed
that
the
DC
voltages are correct, signal tracing may be used
to
deter-
mine
the
point
of
signal loss. The test setup illustrated
in
figure
two
on
page
ten
p
.-
ovides a simple
method
of
injecting
the
proper level signal
at
the
input.
IF
A DEFECTIVE INTEGRATED CIRCUIT
IS
SUSPECTED, remember
that
these are highly
reliable devices with a failure rate equal
to
or
lower
than
those
of
other
components
..
..
DO
NOT
BLAME
THE TROUBLE
ON
AN
I.C
. UNTIL THE POSSIBILITY OF
AN
EXTERNAL COMPON-
ENT FAILURE HAS BEEN THOROUGHLY INVESTIGATED. If
the
I.C.
proves
to
be
the
cause
of
the
trouble,
it
should be replaced as follows:
-
5-

STEAM POWERED RADIO.COM
1. Remove
the
solder from around
all
the
pins
of
the
I.C.
(The use
of
a solder removal
tool such as
the
Edsyn "Soldavac"
is
recommended.
..
lrons
that
heat
all
the
I.C.
pins
at
once are
not
recommended.) Make sure
that
each pin
is
free from
the
P.C. board.
2.
Lift
the
I.C.
from
the
board, bei
ng
careful
not
to
bend any
of
the leads or damage
the
body. (It may still be good.)
3. Insert new I.C. and solder leads
to
P.C. board. Make sure
that
each pin
is
soldered well
and
that
there are no solder bridges between P.
C.
board pads. Do
not
overheat
the
I.C
.
during soldering.
PARTS:
The parts list
on
page seven lists all
of
the commonly needed replacement parts
that
are available
from Russco Electronics. Many
of
these parts may be found
at
local electronics parts houses. When
buying locally, be sure
that
the
correct part
or
an exact equivalent
is
supplied.
Do
not
attempt
to
use "general purpose" devices
or
"experimenters specials". The factory can supply most
of
the
parts
on
the
list in a few days.
RETURNING FOR SERVICE:
Items returned for service should be packed well (preferably
in
the
original carton) and shipped
prepaid
to
the
factory. PLEASE
DO
NOT FAIL TO INCLUDE OR MAIL UNDER SEPARATE
COVER A DESCRIPTION OF THE DEFECT. Retu~n c~ari,es rtill be prepaid if the item
is
in
warranty.
Out
of
warranty items will be shipped freight collect
of
billed.
SPECIAL NOTE ON GROUNDING OUTPUT TRANSFORMER CENTER-TAPS:
In
order
to
reduce noise on a balanced
li
n
e,
it may be necessary
to
ground
the
center-taps
of
the
output
transformers. Remove the circuit board
as
described under DISASSEMBLY. The trans-
former secondary center-
ta
p lead will be found bundled next
to
the
transformer winding.
An
--~
--
unoccupied
P.C.
pad wi
ll
b~
fo
!:Jnd
on
the
P.C. board between
the
points where
the
other
two
transformer secondar~ leads are soldered
to
the
board. Insert
the
center-tap lead
in
this pad and
solder it
to
the
unde~ide
of
the
board. Cut off any excess lead.
WARRANTY
AND
SERI.AL NUMBER
When
ordering parts
or
sub-assemblies under warranty, be sure
to
supply the serial number
of
your
unit. The serial number
will
be found on a label on
the
bottom
of
the
preamp box.
-6
-

STEAM POWERED RADIO.COM
PARTS
LIST---
RUSSCO
FIDELITY-MASTER
AND
FIDELITY-PRO
PREAMPS
SCHEMATIC RUSSCO
REFERENCE PARTS DESCRIPTION PART NO. PRICE*
T1
Power Transformer, Wood 7424 108-005 10.35
T2 Output Transformer, Wood 7425 108-006 14.35
01,2,3,4, Rectifier Diode, 1 Amp, 100vPIV, Semtech SIi 130-007 .60
Op,6 Zener Diode, 13v, IW,
5%,
1N4743A 130-010 .65
07,8
Zener Diode, 10v,
1W,
5%,
1N4740A 130-009 .65
IC1
Integrated Circuit Stereo Preamp, National
LM1303N, Motorola MC1303
or
Fairchild
MuA739
140-002 6.00
IC2 Integrated Circuit Operational Amplifier,
National LM301AN
or
Analog Devices
AD301AN
140-001 3.30
F1
Fuse,
3/10
Amp
Slow Blow, Uttlefuse 3AG
1/10
101-003 .50
C1,2 Capacitor, Electrolytic, Axial,
500mF/50V
110-016 1.15
C3,4
II II II
1mFnov
110-002 .45
C5
II
Tantalum, Dipped,
1mF/35V
110-019 .85
C6,
11,
16,
20,21
II
Ceramic, Di.c, 0.01mF/100V 110-026 .25
C7,
12, 15, 17
II
Tantalum, Dipped, 10mF/35V 110-017 .85
C8
II
Ceramic, Disc, 0.005mF/100V 110-025 .25
C9
II
Mylar,
Axial,
0.001mF/200V/10% 110-020 .45
C10
II
II
II
0.0047mF/200V/10% 110-021 .45
C13
II
Tantalum, Dipped,
0.15mF/35V
110-018 .85
C14
II
Mylar, Axial, 0.01mF/200V/10% 110-022 .45
C18
II
Ceramic, Disc, 5pF/1
KV
110-023 .25
C19
II
Ceramic, Disc, 10pF/1
KV
110-024 .25
C22
II
Electrolytic, Axial, 100mF/35V 110-009 .85
R1,2 Resistor, Deposited Carbon, 220 ohm,
½W,
5%
150-006 .
15
R3
II
II
,,
47Kohm,
¼W,
5%
1150-032 .20
R4
,,
II
,,
820K ohm,
¼W,
5%
1-50
-035 .20
RS
,,
II
,,
2.2K ohm,
¼W,
5%
150-040 .20
R6
II
,, ,,
56K ohm,
¼W,
5%
150-042 .20
R7
II
,, ,,
750K ohm,
¼W,
5%
150-034
1
.. • '
'.
20
J•
R8,9
II
,,
II
100 ohm,
½W,
5%
150-003
.1'5
R10
,,
,,
II
6.8K ohm,
¼W,
5%
150-041 .20
R11
Trimpot,
10K
ohm, Linear Taper,
Cermet Element, Bourns 3389S-1-103 150-043 2.00
R12,14 Resistor, Deposited Carbon, 100K ohm,
¼W,
5%
150-033 .20
R13
II
,,
,,
10K ohm,
¼W,
5%
150-031 .20
R15
,,
,, ,,
22 ohm,
½W,
5%
150-002 .15
-7-

STEAM POWERED RADIO.COM
REPLACEMENT ASSEMBLIES
Rear
Panel
and transformer assembly,
complete, ready
to
plug in:
For Mono
Preamps,
all models
For Stereo Preamps, all models
Front
Panel
and Printed Circuit Board Assembly,
complete, ready
to
plug in:
Fidelity-Master, Mono, Unbalanced (FMMU)
" " " Balanced (FMMB)
" "
Stereo, Unbalanced (FMSU)
" "
" Balanced (FMSB)
Fidelity-Pro, Mono, Unbalanced (FPMU)
" " " Balanced (FPMB)
" " Stereo, Unbalanced (FPSU) ·
;,
"
" " Balanced (FPSB)
..
*
Prices
subject
to
change
wi
thout
notice.
I
NOTE
on
OUTPUT IMPEDANCE
of
BALANCED MODELS:
...,
RUSSCO
PART NO.
400-118
400-117
400-119
400-120
400-121
400-122
400-123
400-124
400-125
400-126
PRICE*
26.75
36.00
45.00
64.00
76.50
114.50
60
.75
79.75
98.50
136.50
Because
of
the l~w reflected impedance
of
the integrated circuit driving the
output
transformer, the
true
output
i,npedance at the secondary
of
the transformer
is
less
than the rated 600 ohms. This
is
' '
q1.
no consequence unlessthe transformer secondary
is
driving a precision attenuator or
filter
which
requires a 600 ohm source
for
proper operation.
In
such
applications, place a 270 ohm resistor in
series
with
each
side
of
the output line. This
will
give
the proper source
ma
t
ch
for
filter
or
attenuator inputs.
-8
-