Cary Audio Design CAD 300 SEI User Manual
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CAD 300 SEI
Single-ended Integrated Stereo Amplier
OWNER’S MANUAL
TABLE OF CONTENTS
Important Safety Instructions ............................................................................................................. 2
Introduction .......................................................................................................................................... 4
Specifications ........................................................................................................................................ 6
Features ................................................................................................................................................ 8
Installation
Unpacking ........................................................................................................................................... 9
Warranty Card...................................................................................................................................... 9
Placement ............................................................................................................................................ 9
Power Requirements ............................................................................................................................. 9
Cables ................................................................................................................................................. 9
Operation
AC On Power Switch ........................................................................................................................... 10
Break-In Period .................................................................................................................................. 10
Bias Adjustment Procedures ................................................................................................................ 10
Diagrams
Bias Adjustment ................................................................................................................................. 11
300B Tube ................................................................................................................................ ......... 12
Tube Placement Chart ......................................................................................................................... 13
Service and Care
Tube Replacement .............................................................................................................................. 14
Factory Service................................................................................................................................... 14
Non-Warranty Repairs ......................................................................................................................... 14
Limited Warranty ................................................................................................................................ 15
IMPORTANT SAFETY INSTRUCTIONS
2
WARNING: The triangle with the lightning flash symbol displayed on the unit advises the user of dangerous
uninsulated voltage inside the product’s enclosure.
CAUTION: To reduce the risk of electric shock, do not remove the cover. There are no user-serviceable parts inside; it
is recommended that only qualified personnel service this component.
ALERT: The triangle with the exclamation point symbol on the component suggests that the owner refer to
important operating and maintenance instructions in the owner’s manual.
1. OWNER’S MANUAL: Before powering up the equipment, read all safety and operating instructions and follow
them as instructed. Retain the safety and operating instructions for future reference.
2. ATTACHMENTS: Use only those attachments recommended by the unit manufacturer, as others may cause
hazards.
3. ACCESSORIES: Do not place the unit on an unstable cart, stand, tripod, bracket, or table. The unit may fall,
causing injury to a person or damage to the unit. Mount the unit according to the manufacturer’s instructions with
the suggested mounting accessory.
4. WALL OR CEILING MOUNTING: Mount the unit to a wall or ceiling only in the manner recommended by the
manufacturer.
5. WATER AND MOISTURE: Do not use the unit near water (for example, near a swimming pool, bath tub, wash
bowl, kitchen sink, or laundry tub) or in a damp environment (like a basement or outside in the rain).
6. OBJECT AND LIQUID ENTRY: Do not push objects of any kind into the unit through openings as they could touch
dangerous voltage points and short-out parts, possibly resulting in a fire or electric shock. Avoid spilling liquid of any
kind on the unit. If water or any metal object (such as a paper clip, coin, or staple) accidentally falls inside the unit,
disconnect it from the AC power source immediately and contact Cary Audio Design for further instructions.
7. HEAT: Position the unit away from heat sources such as radiators, heat registers, stoves, or other units
(including amplifiers) that produce heat.
8. VENTILATION: Slots and openings in the cabinet create ventilation to protect the component from overheating.
These openings on the top and bottom panels must remain unobstructed. Allow at least 6 inches (16cm) of clearance
above the unit and an opening behind the unit for airflow. Do not place the unit on a
bed, sofa, rug, built-in bookcase, or rack without adequate ventilation.
9. GROUNDING OR POLARIZATION: As a safety feature, the unit may be equipped with a polarized alternating
current line plug in which one blade is wider than the other. This plug will fit into the power outlet only one way. If
you cannot insert the plug fully into the outlet, try reversing the plug. If the plug still will not fit, contact a licensed
electrician to update your obsolete outlet. Do not defeat the safety purpose of the polarized plug.
10. POWER SOURCES: Operate the unit only from the power source indicated on the marking label. If you are
unsure of the type of power supplied to your home, consult your unit dealer or local power company.
11. POWER CORD PROTECTION: Arrange power supply cords so that they do not suffer from foot traffic or pinching
by items placed on or against them. Pay close attention to cords where plug enter the AC outlet and where they exit
from the unit.
12. LIGHTNING: For added protection during a lightning storm or when is the component is idle for long periods of
time, unplug the unit from the wall outlet and disconnect the antenna or cable system. This will help protect the
unit from lightning and power line surge damage.
13. POWER LINES: Do not locate an outside antenna system in the vicinity of overhead power lines or other electric
light or power circuits. When installing an outside antenna system, take extreme care to avoid touching the power
lines or circuits; contact with them could be fatal.
14. OVERLOADING: Do not overload wall outlets, extension cords, or integral convenience receptacles as this
increases the risk of fire or electric shock.
IMPORTANT SAFETY INSTRUCTIONS
3
15. REPLACEMENT PARTS: When replacement parts are required, be sure the service technician has used replacement
parts specified by the manufacturer or those having the same characteristics as the original parts. Unauthorized
substitutions may result in fire, electric shock or other hazards.
16. SAFETY CHECK: Upon completion of any service or repairs to the unit, ask the service technician to perform safety
checks to ensure the unit is in proper operating condition.
17. IMPORTANT SAFETY NOTE:
•
Before connecting a new product such as the CD 303T to your audio or home theater system, turn off all other
equipment (preferably unplugging them from the AC power source). Many audio components feature automatic turnon circuits that may activate during an installation, potentially causing damage to electronic components and/or
speakers. This type of damage is not covered by product warranties, and Cary Audio specifically disclaims responsibility
for any such damage.
•
Power Cord: The removable power cord provided with your player was specifically designed for use
with this product, but other AC cords may be used. Consult your dealer for advice on AC power
cords and high quality wire in your system.
•
AC Fuse: The fuse is located inside the chassis and is not user serviceable. If the unit does not
power up, contact an authorized service representative
•
Wiring: Cables running inside walls should have the appropriate markings to indicate compliance and listing by the
UL, CSA or other standards required by the UL, CSA, NEC or your local building code. Questions about cables inside
of walls should be referred to a qualified custom installer, a licensed electrician, or low-voltage contractor.
18. RECORDING COPYRIGHT: Recording of copyrighted material for other than personal use is illegal without
permission of the copyright holder.
19. NOTE TO CATV SYSTEM INSTALLER: This reminder is provided to call the CATV system installer's attention to article
820-40 of the NEC, ANSI/NFPA 70, which provides guidelines for proper grounding and, in particular, specifies that the
cable ground shall be connected to the grounding system of the building as close to the point of cable entry as practical.
20. FCC INFORMATION FOR USER:
•
CAUTION: Any changes or modifications not expressly approved by Cary
Audio Design could void the user's authority to operate the equipment.
•
NOTE: This equipment has been tested and found to comply with the limits for a
Class B digital device pursuant to Part 15 of the FCC Rules.
•
These limits are designed to provide reasonable protection against harmful interference in a residential installation.
This equipment generates and can radiate radio frequency energy, and if not installed and used in accordance with the
instructions it may cause harmful interference to radio communications. However, there is no guarantee that
interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to
correct the interference by one or more of the following measures:
•
Reorient or relocate the receiving antenna.
•
Increase the separation between the equipment and receiver.
•
21. OUTDOOR ANTENNA
•
If an outside antenna or cable system is connected to the equipment, be
•
Outside antenna system should be located well away from power
Connect the equipment into an outlet on a circuit different from where the receiver is connected.
sure the antenna or cable system is grounded in order to provide
protection against built-up static charges and voltage surges. Article 810
of the National Electrical Code, ANSI/NFPA 70 (in Canada, Part 1 of the
Canadian Electrical Code) provides information regarding proper
grounding of the mast and supporting structure, grounding of the lead-in
wire to an antenna discharge unit, size of grounding conductors, location
of antenna discharge unit, connection to grounding electrodes and
requirements for the grounding electrode.
lines, electric light or power circuits and where it will never come into
contact with these power sources if it should happen to fall. When
installing an outside antenna, extreme care should be taken to avoid
touching power lines, circuits or other power sources as this could be fatal. Because of the hazards involved, antenna
installation should be left to a professional.
INSTALLATION/SAFE
ANTENNA AND CABLE CONNECTION:
INTRODUCTION
4
Congratulations!
You have purchased one of the most exotic vacuum tube audio integrated amplifiers available. Within its
power range, the CAD 300 SEI integrated amplifier offers the most realistic sound reproduction one could
desire for a “high-end” home audio system. Careful design, parts selection and proper circuit topologies
contribute to the incredible reliability and enjoyment.
For the technically minded, a review of the circuit is in order. Your new CAD 300 SEI operates in a class A
single-ended mode utilizing an auto bias (cathode) system for the 300B triode output tubes. The input
preamplifier section utilizes a 6SN7 dual triode tube. One triode section of this dual tube is used for the
left channel and the other triode section is used for the right channel. This circuit is a Class A voltage
gain circuit. This is the same basic first stage input circuit utilized in the Cary Audio model SLP 98
preamplifier. The next gain stage in the CAD 300 SEI utilizes a 6SN7 dual triode wired in a series
constant-current plate-loaded configuration. This stage is duplicated for each channel. The series
constant-current configuration then drives the 300B triode output stage in single-ended, class A. The
output transformers in the CAD 300 SEI are the most important components in the amplifier and have
been specifically designed by Cary Audio for use in the CAD 300 SEI. The output transformer is an airgap design with a commercial continuous rating of 200% duty cycle. The CAD 300 SEI output
transformer is an E/I laminate, silicon impregnated, grain oriented steel design. The windings are wax
impregnated and the entire transformer is potted in high temperature wax. Utilizing the linear, directly
heated filament-cathode 300B triode output tube, there is no global feedback used in the CAD 300 SEI.
The power supply is a full wave center tap configuration running high voltage, high current fast switching
diode rectifiers. The rectified 450 VDC is fed to a PI-L filter network. The filter capacitor consists of two
(2) 1200 MFD and 230 Joules of energy storage. Each electrolytic capacitor is by-passed with a low
impedance .22 polystyrene capacitor. The power transformer is a 200% duty cycle rating on the CAD 300
SEI. To avoid AC hum, both the 6SN7 and 300B tube have DC voltage on the filaments. This will prevent
AC ripple voltage from capacitively being coupled to the elements in the tubes.
Additional Design Thoughts
A great deal of attention during the design of your new CAD 300 SEI was concentrated on the “overload
recovery” ability of the amplifier to instantly recover from clipping and is a much more important issue
tan is commonly believed. In the power war of amplifier manufacturers the mentality is focused on high
and then even higher power output to solve the clipping problem. When in reality, the most critical
aspect is how fast a recovery an amplifier can achieve after overload. Most of the music being listened to
in an average listening room is only requiring about 3 watts of power. It is on the transients of loud low
frequency program material that tremendous signal voltages will appear at the input of the amplifier. It is
in this situation that the overload recovery ability of an amplifier is of critical concern. The single-ended
CAD 300 SEI extols its merits in the ability to handle transients and instantaneously recover from brief or
even extended overloads. The CAD 300 SEI will overload symmetrically at any frequency in the audio
band pass. The CAD 300 SEI will also yield faithful reproduction of extremely low frequencies at full
output levels. Power transformer, power supply regulation and output transformer design and careful
shaping of the overall frequency response curve all play a very important part in the ability of the CAD
300 SEI to recover quickly when overloaded. If one were to monitor the high voltage rail voltage (385
VDC at the anode of the 300B tube) of a CAD 300 SEI during soft and loud music passages it will be
found there is no more than a volt or so change from soft to loud passages.
Another technical feature of your new CAD 300 SEI is amplifier stability. The CAD 300 SEI may be
operated with no load (without speaker) without damage to the amplifier, output transformer or tubes.
This is the hallmark of a high performance, STABLE, amplifier circuit design.
INTRODUCTION
5
The most exciting feature of the CAD 300 SEI, aside from how compact and gorgeous it looks, is the
delightful, sensual beauty of the music it recreates. The first thing that will strike you about your CAD 300
SEI integrated amplifier is the incredible transparency and resolution of detail of the music. The CAD 300
SEI sensual nature is best revealed in the sense of life it displays in female vocalists.
Your new CAD 300 SEI presents music with such presence and directness, you’ll be drawn into the music
hour after musically satisfying hour. This is the result of single-ended circuit techniques, which eliminate
crossover notch at low levels and also contributes to the freedom from listening fatigue. The CAD 300 SEI
will draw you in even further as you realize how lucid and utterly uncolored neutrality reveals delicate
nuances in the sound stage.
Enjoy the music!
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