Sunfire Classic Vacuum Tube Preamplifier User Manual
User's Manual
Safety Instructions
1. Read Instructions -– All the safety and operation
instructions should be read before the Sunfire Component
is operated.
2. Retain Instructions — The safety and operating
instructions should be kept for future reference.
3. Heed Warnings — All warnings on the Component and
in these operating instructions should be followed.
10. Cleaning — The Component should be cleaned only
as recommended in this manual.
11. Non-use Periods—The power cord of the Component
should be unplugged from the outlet when unused for a
long period of time.
12. Object and Liquid Entry — Care should be taken so
that objects do not fall into and liquids are not spilled into
the inside of the Component.
4. Follow Instructions — All operating and other instructions should be followed.
5. Water and Moisture — The Component should not be
used near water - for example, near a bathtub, washbowl,
kitchen sink, laundry tub, in a wet basement, or near a
swimming pool, etc.
6. Ventilation — The Component should be situated so
that its location or position does not interfere with its
proper ventilation. For example, the Component should
not be situated on a bed, sofa, rug, or similar surface that
may block any ventilation openings; or placed in a built-in
installation such as a bookcase or cabinet that may
impede the flow of air through ventilation openings.
7. Heat — The Component should be situated away from
heat sources such as radiators, or other devices which
produce heat.
8. Power Sources — The Component should be connected
to a power supply only of the type described in these operation instructions or as marked on the Component.
9. Power Cord Protection — Power-supply cords should be
routed so that they are not likely to be walked upon or
pinched by items placed upon or against them, paying
particular attention to cords at plugs, convenience receptacles, and the point where they exit the Component.
13. Damage Requiring Service — The Component should
be serviced only by qualified service personnel when:
A. The power-supply cord or the plug has been damaged; or
B. Objects have fallen, or liquid has spilled into the
Component; or
C. The Component has been exposed to rain; or
D. The Component does not appear to operate normally
or exhibits a marked change in performance; or
E. The Component has been dropped, or its cabinet damaged.
14. Servicing — The user should not attempt to service
the Component beyond those means described in this
operating manual. All other servicing should be referred to
qualified service personnel.
2
Safety Instructions
User's Manual
15. To prevent electric shock, do not use this polarized
plug with an extension cord, receptacle or other outlet
unless the blades can be fully inserted to prevent blade
exposure.
Pour préevenir les chocs électriques ne pas utiliser cette
fiche polariseé avec un prolongateur, un prise de courant
ou une autre sortie de courant, sauf si les lames peuvent
être insérées à fond sans laisser aucune pariie à
découvert.
16. Grounding or Polarization — Precautions should be
taken so that the grounding or polarization means of the
Component is not defeated.
WARNING: TO REDUCE THE RISK OF FIRE OR
ELECTRIC SHOCK, DO NOT EXPOSE
THIS APPLIANCE TO RAIN OR
MOISTURE.
Contents
This apparatus does not exceed the Class A/Class B
(whichever is applicable) limits for radio noise emissions
from digital apparatus as set out in the radio interference
regulations of the Canadian Department of Communications.
ATTENTION — Le présent appareil numérique n'émet pas
de bruits radioélectriques dépassant las limites
applicables aux appareils numériques de class A/de class
B (selon le cas) prescrites dans le règlement sur le
brouillage radioélectrique édicté par les ministere des
communications du Canada.
WARNING: ALWAYS FULLY INSERT THE PLUG
INTO THE AC SUPPLY SOCKET.
Safety instructions ..................................................................................... 2-3
Introduction .................................................................................................. 4
Features ....................................................................................................... 4
Unpacking .................................................................................................... 4
Overview ...................................................................................................... 5
Front panel features .................................................................................. 6-7
Rear panel features ...................................................................................8-9
Installation, AC power and connections ..................................................... 10
Care............................................................................................................ 10
The Phono stage ................................................................................... 11-12
System Configurations ............................................................................... 13
Phono connections ................................................................................ 13
CD player connections ........................................................................... 14
Tape deck connections .......................................................................... 15
Amplifier connections: unbalanced ........................................................ 16
Amplifier connections: balanced ............................................................ 17
Specifications ............................................................................................. 18
Troubleshooting guide........................................................................... 19-21
Appendix .................................................................................................... 22
Changing the phono stage gain ............................................................. 22
Changing the phono stage input impedance ......................................... 22
Tube type and location .......................................................................... 22
Limited Warranty ........................................................................................ 23
Service assistance ..................................................................................... 23
To find out more about this and other Sunfire products,
please visit our website: www.sunfire.com
Safety Instructions and Table of Contents
3
User's Manual
Introduction
Dear Friend,
Congratulations on your purchase of the Sunfire
Classic Preamplifier. We believe its sophisticated
engineering and meticulous craftsmanship will
provide you with many years of listening enjoyment.
At the heart of the Classic is a high-performance control preamplifier with extremely low noise
and distortion, wide dynamic range, and a high
degree of control flexibility. An optional phono board
may be added for precise RIAA phono equalization
of moving magnet and moving coil cartridges. Your
Classic will provide remarkable three-dimensional
realism, with a sumptuous sonic image which can
extend beyond the loudspeakers in both breadth
and depth.
Bob Carver, Amplifier Designer, Physicist
Unpacking Features
Your Classic preamplifier should reach
you in perfect condition. If you do notice any
shipping damage, please contact your Sunfire
Dealer immediately.
Gently remove the Classic preamplifier
from its packing materials with care, so as to
avoid damage to or loss of any packing
materials. This is a precision instrument and
deserves to be treated with care. It has been
designed to provide years of reliable service,
and should you ever need to ship or transport
it, the original packing materials will provide
the safest means.
Make sure that you keep your sales
receipt. It is the only way to establish the
duration of your Limited Warranty and it may
come in useful for insurance purposes.
Please take a moment to fill out and mail
the Sunfire Warranty Registration card. Also
read the serial number located on the rear
panel and record it here:
• High quality vacuum tube design
• 6 L/R pairs of unbalanced inputs
• Optional MM and MC Phono section
• 2 pairs of unbalanced main outputs
• 1 pair of balanced outputs
• 1 pair of tape outputs
• Low frequency contour control
• High frequency contour control
• Tape monitor switch
• Stereo/mono switch
• Motorized volume control
• Balance control
• Remote control of volume, mute and
power
• 3 unswitched AC outlets
Serial Number:
Purchased from:
Date:
4
Introduction
• Gold-plated inputs and outputs
• Classic chassis and styling
Overview
The Classic is a preamplifier control
center. If you have previous experience with
stereo components, you can probably complete the input/output connections and make
normal use of the basic preamplifier functions
without special instructions. We recommend,
however, that you read the entire manual at
your earliest convenience. You will find that
even some of the “conventional” parts of the
Classic are in fact not conventional at all.
Mute
Power
on/off
User's Manual
Note: The remote control
will only work when the
front panel power switch
is in the ON position.
Gain
control
Power
on/off
1000
WATTS
TOTAL
AC
outlets
2 AMP
AGC
E
S
U
F
AC
cord
Mono/
Stereo
U
N
S
W
I
T
C
H
E
D
REPLACE WITH
ORIGINAL TYPE
AND RATING
ONLY
120 VAC
50/60 Hz
Fuse
Tape
Monitor
BALANCED
TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
XLR
outs
Tone
on/off
OUTPUTS LINE INPUTS
USE EITHER
MAIN 1 MAIN 2 TAPE TAPE AUX VIDEO CD TUNER
L
R
S/N
WARNING
Main
outs
selector
Tape
out
Input
L
R
Tape
Contour (tone)
in
inputs
controls
Line
Balance
PHONO/LINE INPUTS
PHONO
MOVING
MOVING
COIL
MAGNET
L
R
PASSIVE PRECISION
INVERSE RIAA PHONO NETWORK
Optional
Phono
section
PHONO
OUT
INVERSE
PHONO
LINE
IN
MM/MC
switch
Overview
5
User's Manual
Front Panel Features
4
1 5 6 7 8 11 10 9
2 3
1. Power Switch
This is the main AC power switch. Flip the switch up to
apply power to the unit. It is good practice to turn the
volume control down before turning on, and keep it
down until after about 40 seconds of tube warm-up
time (when the MUTE lamp turns off, and the ON
lamp stops blinking and turns on continuously).
If you prefer, you may leave this AC power switch
permanently on, and use the remote control to switch
the unit on or off. Turning the power off with the
remote will extinguish both the MUTE and ON lamps.
Note: the power switch must be in the up (POWER)
position for the remote control to work.
2. On lamp
During normal operation this lamp will be on. When
you turn the preamplifier on, this lamp blinks for about
40 seconds while the tubes are warming up. After that
time, it will stay on continuously.
3. Mute lamp
During normal operation, this lamp will be off. When
you turn the preamplifier on, this lamp stays on for
about 40 seconds while the tubes are warming up,
indicating that the outputs are muted and no sound is
passed to your amplifiers. The lamp will also indicate
whenever the remote control MUTE is pressed.
If you accidentally turn off the preamplifier using the
remote, you can quickly turn it back on. The preamplifier will automatically sense that there is no need for a
40 second mute because the tubes are already
warmed up.
4. Remote window
This window should be kept clear of obstruction for
the remote control to work.
5. Stereo/Mono Switch
This sums the left and right inputs so the main outputs
will have identical signals. (It does not affect the Tape
outputs).
The most common use for this switch is in checking
loudspeaker phasing: Play any stereo or mono
recording, select Mono and listen. Then reverse the
polarity (+, -) of one speaker connection and recheck.
The polarity position which develops a clear center
image between the speakers with fullest bass content
is the correct “in-phase” position of the speaker wiring.
You should also engage Mono for playback of old
monophonic sources, since this will cancel most
rumble and noise for quieter playback.
When listening to a single-channel source, you can
either use a “Y” cord at the selected input, or select
Mono.
6. Tape Monitor switch
This will connect the output of a recorder to the
subsequent preamplifier circuitry. It may be used for
tape playback or record-monitoring with three-head
recorders. Similarly, if a signal processor is connected
to the preamplifier’s Tape inputs and outputs, it will be
in circuit whenever the Tape Monitor switch is engaged.
6
Front Panel Features
User's Manual
7. Contour On/Off
In the OFF position, the contour circuits are bypassed
and the two contour controls (11) will have no effect.
In the ON position, the signal frequency response can
be adjusted by the contour controls to suit your taste.
8. Input Program Selector
This rotary switch selects the program source which
will be heard. The same program source is also
presented to the Tape outputs for recording. Note that
there is no Tape selection, you should engage the
Tape Monitor switch to listen to your tape deck.
If you have the optional Phono input, select either MM
or MC using the rear panel switch (depending upon
your phono cartridge), and then select CD/Phono.
To minimize bleedthrough, or an audible signal when
you select an unused input, it is recommended that
“shorting plugs” be inserted in all unused inputs. Do
Not install shorting plugs in any OUTPUT jacks, as
this would short-circuit the preamplifier output. If you
do not use shorting plugs, that is perfectly OK., and
you can prevent bleedthrough by turning off or muting
all signal sources not being listened to.
9. Volume Control
This is the master level control for the stereo system.
The control is a continuous taper potentiometer to
allow smooth transition from one level to another.
The taper rate of the potentiometer was chosen to
provide maximum flexibility and compatibility with
other components. Input signal levels will vary from
one source to the next, as well as from one disc, tape,
or FM station to the next, so it is normal to notice that
your preferred volume control setting varies.
Note: The remote control’s Volume Up function is
disabled when the system is muted or warming up.
This is to prevent causing damage to your speakers
due to accidentally high volume levels. The remote’s
Volume Down function is available at all times, and
you can still set the volume at any time using the front
panel control (but make sure it is turned down while
the preamp is warming up).
10. Balance Control
This adjusts the relative levels of the two stereo
channels. In its center position, the levels are exactly
equal. Clockwise rotation reduces the Left channel
level, while counterclockwise rotation reduces Right
channel level. Small movements off-center produce
smaller shifts in the stereo image per degree of
rotation than near the extreme left and right position.
This makes slight trimming of levels more convenient.
11. Contour Controls
The Sunfire Classic is equipped with a tone-control
stage in the signal path after all input selection and
tape switching. These controls are switches which
select a variety of precise contour curves. In operation, a muted click or pop may be heard when changing switch positions. The controls may be switched in
or out of circuit by the contour switch (7), allowing the
contoured signal to be quickly compared with the
preamplifier’s laboratory-flat frequency response.
The contour controls are asymmetrical in boost and
cut. They have been designed to be very appropriate
for real music listening situations. The boost exhibits
no shelving, and reaches a maximum of +6 dB at full
clockwise rotation. Bass may thus be boosted without
the boom associated with shelving, in order to increase deep punch without mid-bass fatness. Treble
boost will field greater definition, without the shrillness
which results from treble-boost shelving.
In the cut (counterclockwise) position, treble and bass
are not rolled-off, as with most tone controls, rather
energy output in the upper and lower ranges is
reduced while maintaining flat frequency response in
those ranges. Cut does not exceed -10 dB, since
frequency response attenuation beyond this yields a
dead sound character which is not musically advantageous. Cut is not substantially affected by the toneturnover frequency switches. This shelving characteristic for the cut mode is very useful, for example, if a
recording sounds too bright. The relative harmonic
energy can be reduced without affecting the balance
of the harmonic content. Thus, a violin will still sound
like a violin, retaining its air, sheen and openness,
while reducing excessive brightness.
Note: We encourage the routine use of the contour
controls as this will significantly enhance your listening
pleasure.
Front Panel Features
7
User's Manual
Rear Panel Features
4 5 6 7 8 9 10 11 12 13 14
U
N
3
2
1000
WATTS
TOTAL
2 AMP
AGC
1
S
W
I
T
C
H
E
D
REPLACE WITH
ORIGINAL TYPE
FUSE
AND RATING
ONLY
120 VAC
50/60 Hz
BALANCED
OUTPUTS LINE INPUTS
MAIN 1 MAIN 2 TAPE TAPE AUX VIDEO CD TUNER
L
R
S/N
TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK
DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
1. AC Line Cord
This is heavy-duty cord capable of
carrying large currents required by highpower amplifiers. The Classic itself
requires only modest power (equivalent to
most light bulbs) and may thus be powered by a conventional extension cord if
required. But if you have substantial
power amplifiers connected to one of the
convenience outlets, only use a heavy
duty extension cord (16 gauge or thicker).
The line cord should only be plugged in
after completing all input and output
connections to other components.
2. Fuse
Always unplug the power cord
before inspecting or changing the
fuse. Never use a fuse with a
larger current rating than 2 A.
3. Accessory outlets
These three unswitched AC outlets are
LIVE whenever the unit’s line cord is
plugged into an active AC receptacle.
They can be used to supply AC power to
other components of your system,
including your amplifier. The total power
draw must not exceed 1000W.
USE EITHER
WARNING
PHONO/LINE INPUTS
MOVING
COIL
L
R
L
R
INVERSE RIAA PHONO NETWORK
PHONO
MOVING
MAGNET
PASSIVE PRECISION
PHONO
OUT
INVERSE
PHONO
LINE
IN
If your power amp is not equipped with a
power switch, make sure that the
preamplifier’s power switch is OFF
(indicator LED is not lit) and its AC linecord is unplugged, before connecting the
power amp’s line cord to one of the
Classic’s outlets.
4. Balanced outputs
These are the left and right outputs which
connect to the balanced inputs of an
amplifier used to drive your speakers.
Balanced outputs offer superior noise
cancellation, especially if there is a long
cable run to your amplifier.
5. Main 1 and Main 2 outputs
MAIN 1 - These are left and right unbalanced (RCA) outputs which connect to
the unbalanced inputs of an amplifier
used to drive your main front speakers.
MAIN 2 - Identical to Main 1. They can be
used to drive a second power amplifier,
such as in bi-wire or multiple speaker
applications, to drive a subwoofer, or to
feed processed signals to a tape recorder
or a time-delay accessory.
15
16
Verify that all component power-switches
are OFF before plugging any component
line cords into these or any AC outlets.
8
Rear Panel Features
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