Cayin m-845D User manual

VACUUM TUBE MONO BLOCK POWER AMPLIFIER
-845D
m
REV：1.1
User's Manual

Table of Contents
Thanks for choosing CAYIN M-845D vacuum tube mono block power and please read the user's
manual carefully before installation and operation.
In order to prevent damage during transportation, the amplifier is packed with protective foams surrounding
the tubes. Before installation and operation, please remove these foams to avoid any risks.
amplifier
Table of Contents
Package Contents…………………………………………………………………………………………………………2
Product Features…………………………………………………………………………………………………………3
Safety Precautions………………………………………………………………………………………………………3
Specifications………………………………………………………………………………………………………………4
Maintenance………………………………………………………………………………………………………………5
Warranty Service…………………………………………………………………………………………………………5
Precautions…………………………………………………………………………………………………………………6
Front Panel…………………………………………………………………………………………………………………7
Rear Panel…………………………………………………………………………………………………………………8
Top Panel……………………………………………………………………………………………………………………9
Installation………………………………………………………………………………………………………………10
Tube Replacement ……………………………………………………………………………………………………10
Audio Connection………………………………………………………………………………………………………11
Speaker Connection……………………………………………………………………………………………………12
Turn on……………………………………………………………………………………………………………………13
Small Tips…………………………………………………………………………………………………………………13
Troubleshooting ………………………………………………………………………………………………………14
How to Install Vacuum Tubes…………………………………………………………………………………………15
……………………………………………………………………………………………… 1…………
1

Please carefully check the package first and then open it.
Package contents include:
1. CAYIN M-845D 1 piece
2. Main Fuse 2 pieces
3. Power cord 1 piece
4. Users' Manual 1 piece
Please make sure local voltage level is matched with the input level of the amplifier, which indicates on the rear
panel. Too low or too high voltage may cause problem. Please contact our company or our local agent if you've found
improper voltage.
Recommendation:
Keep all packing materials for future use .
CAYIN M-845D vacuum tube mono block power amplifier
and reaching the best results. We are not responsible for problems and damages caused by non-original parts
replacement in the amplifier.
is designed and manufactured with our original parts
NOTE:
2
Package Contents
All other parts except above are not included.
NOTE:

1. Unplug the power cord if you are not going to use the product for an extended period of time.
2. The machine will become hot after working for a long time. Please keep the unit's ventilation open and
install the amplifier at a well-ventilated place to avoid troubles and fire hazard.
3. Forbidden to operate when the output is open or shorted.
4. Do not attempt to service this product yourself. Opening the cover may expose you to dangerous
voltage or other hazards.
5. We are not responsible for any problems caused by checking and opening without permission of our
company. For service, Please contact a qualified service technician.
6. Do not place any objects filled with liquids such as vases or some others on the top or around.
7. Clean only with dry cloth.
8. Please move the amplifier carefully not to drop the unit or be subject to other strong shocks.
3
Product Features
Safety Precautions
◆ Hand-made construction with the finest point-to-point wiring
◆ EI output transformer with wide bandwidth and push transformer are applied.
◆ Specially designed toroid transformer for power supply.
◆ One piece of 6SN7 has been used in the preamp stage for voltage regulation.
◆ Two pieces of 6SN7 has been used for voltage amplification.
◆
◆ Switchable between different negative feedbacks. NFB.-0dB, NFB.-2dB, NFB.-3dB, NFB.-4dB, NFB.-5dB
can be chose under different hearing environment.
◆ User Bias adjustment, Hum Balance adjustment are accessible on top of the amplifier with true ampere
meter.
◆ BALANCE and RCA input function.
◆
◆
◆ Time-delay power supply for both high/low voltage and preheated filament to prolong tube's life.
◆
◆
TJ Full Music 300B with Porcelain base has been used for drive amplification. 845 vacuum tube has been
used for Single-end Class A amplification.
High quality German WBT top grade Speaker terminals, USA Multicap Capacitors and Japanese Takman
Carbon Film Audio grade resistors have been used in the amplifier.
High-grade gold-plated porcelain tube socket is used to raise reliability of connection.
Thickly silver plated signal cables and connectors have been used.
Equipped with easily-installed aluminum tube cover for protection.

4
Specifications
◆ To reduce the risk of electric shock, do not remove the cover.
◆ No user serviceable parts inside. Refer servicing to qualified service
personnel.
◆ To reduce the risk of fire or electronic shock, do not expose the unit to
rain or moisture.
The lightning flash with arrowhead symbol is intended to alert user to the presence of uninsulated
“dangerous voltage” within the product's enclosure that may be of a risk shock to persons.
The exclamation point is intended to alert user to the presence of important operation and maintenance
(servicing) instructions accompanying the appliance.
Power Output
60W
Frequency Response
15Hz~28kHz (-3dB)
THD
0.3%(1W/1kHz;5% Under Rated Power)
Sensitivity
RCA:750mV
BALANCE:1500mV
S/N Ratio
89dB
Input Impedance
100kΩ
Output Impedance
0,4Ω , 8 Ω ,16Ω Ω Ω Ω
Input Terminals
BALANCE, RCA
NFB. Selection
0dB，-2dB，-3dB，-4dB，-5dB
Tube
845×2、300B×1、6SN7×3
WDH
480mm×577mm×252mm
Net Weight
50kg
Max Power Consumption
380W
Working Condition
Temperature：0℃～40℃ Moisture：20%～80%
Storage Condition
Temperature：-20℃～70℃ Moisture：20%～90%

Warranty Service
1.This product is warranted for a period of twelve months beginning from the date of purchase.
2.The defective product must be returned to your dealer or our company for repairing when your dealer or our
company accepts your requirement.
3.The warranty doesn't extend to any product that has been opened by you without permission of our company.
Maintenance
5
NOTE:
◆
◆ Do not use any chemicals for cleaning.
Use the soft dry cloth to clean up the chassis regularly.
The information in this manual is subject to change without
further notice.
NOTE:

Precautions
◆ Connect the power only after finishing other connections.
◆ It is normal that power transformer becomes hot for extended period of operation.
◆ Unplug the power cord if you're not going to use the product for an extended period of time.
◆Please make sure corresponding voltage is the same as required. We are not responsible for damage caused by misuse
of unsuitable voltage.
6
Connection of power cord:
Connect the speaker cables and signal cable first and then insert the power cord into the power socket.
NOTE:
YALIDA YN-401
Connected to AC INPUT
Connected to power socket

7
Front Panel
1.Power Indicator/Mute Indicator
Used to indicate the working state. The green
indicator will be on when it is working normally.
The red indicator will be on when it delays to
work. The indicator will keep flickering for 30
seconds when it delays to work under high
voltage.
2.Power Switch
Used to switch on/off the amplifier.
Note: Unplug the power cord if you're not going
to use the product for an extended period
of time.
3.NFB.Indicator：
The NFB. 0dB indicator will be on when it is NFB.0dB.
The NFB. -2dB indicator will be on when it isNFB. -2dB.
The NFB. -3dB indicator will be on when it is NFB.-3dB.
The NFB. -4dB indicator will be on when it is NFB.-4dB.
The NFB. -5dB indicator will be on when it is NFB.-5dB.
2
1 3

8
Rear Panel
1. BALANCE Signal Input Terminal
Used to connect balance output terminal.
2. Signal Input Selector
Used to choose BALANCE or RCA signal.
3. NON-BALANCE Signal Input Terminal
Used to connect non-balance output terminal.
4. NFB.Indicator
Used to choose different negative feedbacks.
5. BIAS Selector Knob
Used to choose the vacuum tube needs
adjustment. Put it at “off” after the adjustment.
6. Channel Output
Used to connect with the channel of speaker.
7. Power Socket with Main Fuse
Main fuse is located just below the power socket.
Replace the fuse with the same type and value.
7
1 2 3 4 56

Top Panel
9
1.Be careful of the high temperature of the tubes during operation.
2.Replace the tubes carefully and correctly.
3.Power tubes must be matched for well function.
NOTE:
1.845 Tube
2.300B Tube
3.845 Tube Hum Adjustment Knob
Used to adjust the 845 tube hum sound. You can adjust the 845 hum sound to the lowest by knobbing
deasil or widdershins.
4.845 Tube Bias Adjustment Knob
1). Choose the tube by BIAS SELECTOR knob; adjust the according BIAS ADJ. Knob; adjust the pointer of
BIAS meter to the center. Please make the adjustment once more for making the specification of tube
consistent.
2).Once finished bias adjustment please turn BIAS SELECTOR to the position of "OFF".
5.845 Tube Indicator
6.6SN7 Tube
7.NFB.Selector Knob
8.BIAS Selector Knob
9.BIAS Meter
Installation and Tear down of 845 Tube: Turn the tube deasil when installation and turn it widdershins when
tear down.
Installation and Tear down of 300 Tube: Install and tear down the 300B vertically.
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