Cayin CS-55A User manual

Vacuum Tube Integrated Amplifier
CS-55A
ON OFF
VOLUME
MI N MAX
SELECTOR
POWER
TR/ UL
VACUUM TUBE INTEGRATED AMPLIFIER CS-55A
PHONES
PHONOCD
AUX USB
REV：1.1
User's Manual

Table of Contents
Thanks for choosing CAYIN CS-55A Integrated Amplifier 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.
Vacuum Tube
1
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
Remote Control…………………………………………………………………………………………………………10
……………………………………………………………………………………11
…………………………………………………………………………………11～12
Installation………………………………………………………………………………………………………………13
Tube Replacement ……………………………………………………………………………………………………13
Audio Connection………………………………………………………………………………………………………14
Speaker Connection……………………………………………………………………………………………………15
Turn on……………………………………………………………………………………………………………………16
Small Tips…………………………………………………………………………………………………………………16
Troubleshooting ………………………………………………………………………………………………………17
How to Install Vacuum Tubes…………………………………………………………………………………………18
……………………………………………………………………………………………… 1…………
Operation System Requirement
Installation of the driver software

Please carefully check the package first and then open it.
Package contents include:
1. CAYIN CS-55A 1 piece
2. Remote Control 1 piece
3. (AAA) Battery of 1.5V 2 pieces
4. Users' Manual 1 piece
5. Power cord 1 piece
6. USB cord 1 piece
7. 1 piece
8. Main Fuse 2 pieces
Driver CD
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 CS-55A Vacuum Tube Amplifier is designed and manufactured with our original parts and
reaching the best results. We are not responsible for problems and damages caused by non-original parts
replacement in the amplifier.
Integrated
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.
◆ Two EI output transformers with wide bandwidth are applied.
◆ Specially designed toroid transformer for power supply.
◆ Audio grade capacitors and resistors are used for a better and more sweet sound output.
◆ 12AX7/ECC83 and 12AU7/ECC82 tubes are used in the preamp stage.
◆ Four KT88/EL34 tubes are used for AB1 push-pull amplification.
◆ Triode and Ultralinear selection.
◆ External user Bias Adjustment is accessible with the BIAS meter for monitoring on the top of the amplier.
◆ External Tube Selection Switch between EL34 and KT88 on the rear panel for easy tube replacement.
◆ Four pairs of input include one USB input, one Phono input and two line inputs.
◆CS-55A takes outstanding USB audio technology which utilizes high speed USB 2.0 receiving and decoding
32bit/384kHz high resolution digital signals.Internal USB DAC which supports asynchronous clocking.
◆ Equipped with remote control.
◆ Soft start function (about 30 seconds).
◆ CS-55A can memorize last operation of the unit once turned off.
◆ High-quality Japanese ALPS motor potentiometer.
◆ Equipped with easily-installed 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.
Description EL34 TUBE KT88 TUBE
AMPLIFIER
Power Output TR:20W+20W (RMS )
UL:38W+38W (RMS )
TRIODE
ULTRALINEAR
TR:22W+22W (RMS )
UL:40W+40W (RMS )
TRIODE
ULTRALINEAR
Frequency
Response 5Hz～48kHz (-3dB) 5Hz～44kHz (-3dB)
THD 1%(1kHz) 1%(1kHz)
S/N Ratio 92dB 92dB
Input Sensitivity 280mV 270mV
Input Impedance 100kΩ100kΩ
Output Impedance 4Ω, 8Ω4Ω, 8Ω
Input Terminals USB，PHONO，CD，AUX USB，PHONO，CD，AUX
WDH(W×D×H) 3
360mm×334mm×180mm 3 360mm×334mm×180mm
Tube 12AX7/ECC83×2、12AU7/ECC82×2、EL34×4 12AX7/ECC83×2、12AU7/ECC82×2、KT88×4
Net Weight 17kg 17kg
Max Power
Consumption 270W 270W
USB DAC
Compatible with Audio Class 1.0 and Audio Class 2.0
Word length：16 - 32bits
Sampling rate：44.1kHz, 48kHz, 88.2kHz,96kHz,176.4kHz,192kHz,352.8kHz,384kHz
® ® ® ®
Operating System：Windows XP , Windows Vista ，Windows 7 , Windows 8 , Mac OS(10.6.3
and above)
PHONO
Input Sensitivity：3mV
Input impedance：47kΩ
RIAA Errors：Lower than ±0.25dB
Total Gain：40dB
S/N ratio：68dB
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:
ON OFF
VOLUME
MI N MAX
SELECTOR
POWER
TR/ UL
VACUUM TUBE INTEGRATED AMPLIFIER CS-55A
PHONES
PHONOCD
AUX USB

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 cables first and then insert the power cord into the power socket.
NOTE:
YALIDA YN-401
Connected to AC INPUT
Connected to power socket
MODEL : CS - 55A
SER.NO. :
VACUUM TUBE INTEGRATED AMPLIFIER
INPUT
CD AUX PHONO
GND
RIGHT OUTPUT LEFT OUTPUT
USB
ZHUHAI SPARK ELECTRONIC EQUIPMENT CO.,LTD.
TUBE SEL.
EL34
KT88

7
Front Panel
①Power 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. Headphone Jack（PHONES）
Enjoy the music with your headphone if you
prefer.
Power Indicator/Mute Indicator
Used to indicate the working state. The indicator
will be on when it is working normally. The
indicator will flicker for 30 seconds when it
delays to work. The indicator will keep flickering
when it is at mute state.
Volume Knob
Used to control volume
If the TR/UL LED is Yellow it is working at
TRIODE mode.
.
②. Power indicator
Turn on the amplifier the power indicator will be
on.
④.
⑤.
⑥.TR/UL Indicator：
Or it is Utralinear working model with a Red LED.
Once turned on it will keep working at the same
mode before switching off.
Input Selector Indicator
You can hear sound from AUX when AUX
indicator is on.
You can hear sound from CD when CD indicator
is on.
You can hear sound from PHONO when PHONO
indicator is on.
USB Input Indicator: Once USB input has been
selected the indicator will light.
Cayin CS-55A can memorize last operation of
the unit once turned off.
⑧.IR Remote Sensor
Used to receive the code of remote control.
Input Selector Knob
Used to select four kinds of audio
sources.The input selection indicator will be
on according to the input audio sources.This
function can be operated on the remote
control.
⑦.
⑨.
68 59
3
14
27
ON OFF
VOLUME
MI N MAX
SELECTOR
POWER
TR/ UL
VACUUM TUBE INTEGRATED AMPLIFIER CS-55A
PHONES
PHONOCD
AUX USB
Diagram 1：CS-55A FRONT

8
Rear Panel
①.USB Interface
Connect to the computer with USB cable.
②.Ground
Ground for Phono input
③.Signal Input Terminal
Used for audio source input.
④.Tube Selector
Select tube EL34 or KT88 .
⑤. Right Channel Output
Used to connect with the right channel of speaker.
⑥. Left Channel Output
Used to connect with the left 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.
Method of Power Tube Replacement:
1. Refer to the "Tube Replacement" on page 13 and
find out which kind of tubes can be used for
replacement for CS-55A amplifier.
2.Tube Sel. switch on the rear panel must be turned to
position KT88 if you are going to use KT88 series of
tubes for replacement.
3.Tube Sel. on the rear panel must be turned to
position EL34,if you are going to use EL34 series of
tubes for replacement. Bias adjustment instruction
please refer to the manual instruction on page 9.
Please turn off the amplifier when you are
turning the Tube Sel. Switch.
1342 4 5 6 7
MODEL : CS - 55A
SER.NO. :
VACUUM TUBE INTEGRATED AMPLIFIER
INPUT
CD AUX PHONO
GND
RIGHT OUTPUT LEFT OUTPUT
USB
ZHUHAI SPARK ELECTRONIC EQUIPMENT CO.,LTD.
TUBE SEL.
EL34
KT88
Diagram 2：CS-55A BACK

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.
②.
③.
④. V3、V4:12AU7/ECC82 Tube
⑤. V1、V2:12AX7/ECC83
⑥.
Bias Selector Switch(A1、A2、A3、A4)
Used to select corresponding tube for bias
adjustment.
Bias Adjustment Switch(A1、A2、A3、A4)
Used to adjust bias of corresponding power
tube(A1、A2、A3、A4)
Turn the Tube SEL. to position KT88 on the rear
panel, if you are going to use KT88 Tube.Turn the
Tube SEL. to position EL34 on the rear panel, if
you are going to use EL34 tube.
Bias Meter
Used to monitor the working current of the
power tube.
A1、A2、A3、A4:KT88/EL34 Tube
Tube
A
Diagram 5
Bias meter during working
Note: When working normally,
the pointer should stay within
the A zone, still , it would move
for the voltage fluctuation.
Diagram 4
Bias meter when not working
1 2 3 3 612 4 5
Diagram 3：CS-55A TOP
Bias adjustment for the power tube:
Turn the BIAS SELECTOR Switch to the
power tube you are preparing to adjust. Adjust
the corresponding BIAS ADJ. small knobs with
flat screwdriver, and inspect the BIAS meter on
the top panel and make sure the pointer keeps
in the center. Bias adjustment for A1, A2, A3,
and A4 are the same. After all have been
adjusted, do it one more time, to make sure all
the bias level of A1, A2, A3, and A4 are the
same.
Sample of Bias adjustment for power tube
A1:
1. Turn the BIAS SELECTOR Switch to A1;
2. Turn the BIAS ADJ. knob A1, until the
pointer of the bias meter keeps in the center.
The same for A2, A3, A4.

10
Remote Control
Installation
1.Place the remote control upside up. Screw the rear
cover open with the screwdriver.
2. Pull out the battery case carefully (do not break the
wires connected).
3. Put in the batteries with correct polarity.
4. Push in the battery case and screw the rear cover
close.
1. TR/UL
2. Audio Source Input Selector
3. Mute Button
4. Volume Control Selector
Selector
Effective Distance：about 6m
◆Don't drop the remote control. Keep the remote control dry.
◆
◆
◆
◆
Replace the batteries timely.
Don't mix new and old batteries together and use the
batteries with the same specification.
Take out the batteries if you don't use the remote control for
an extended period of time.
Batteries with high quality are recommended.
NOTE:
ON OFF
VOL U ME
MIN MAX
SELECTOR
POWER
TR/ UL
VACUUM TU BE INTEGRATED AMPLI FIER CS-55A
PHON ES
PHON OCD
AUX USB

Operation system requirement
11
Install the USB Audio driver software first
before using the PC-DAC input. Please check as
following for the procedures.
1.Connect the amplifier and computer with USB
cable.
2.Put the driver CD into your computer and open
the files. Double-click “ ”to run the diver
installer. As below:
3. Click“Next”to choose the installation
location.
Computer should meet the following requirements if you are going to use USB audio:
1.Hardware requirement:
◆ Intel or AMD CPU with 1.2GHz or higher processing speed.
◆ Higher than 512MB system RAM.
◆ High speed USB 2.0 socket.
2.Operation system requirement:
◆ Windows system: Microsoft Windows XP、Windows Vista , Windows 7® and Windows 8®
◆ Mac OS X system: Apply OS X (10.6.3 or above)
◆ Other system: No support for Linux system or others.
3.Suggested Media player:
◆ Windows system: Foobar 2000 media player (1.0 or above)
◆ Mac OS X: Audirvana media player
Installation of Driver Software

12
4. Select the installation location and click Install to
begin installation of the driver software.
5. Click Finish to finish installation of the driver
software and install USB Audio Class 2.0 driver
software.
6. Click Install to begin installation of USB Audio
Class 2.0 driver software.
7. Click Finish to finish installation of USB Audio
Class 2.0 driver software.
8. In Media player please choose Cayin USB DAC
as the output instrument and then you can
music by USB DAC of the CS-55A amplifier.
Note: No need to install the driver software for Mac
System.
Installation of Driver Software

Carefully read and follow the manual for installation:
◆
produce heat.
◆ In order to avoid being overheated please keep the unit's ventilation open.
◆ Do not expose this appliance to rain or moisture.
◆ Keep the amplifier in a certain distance so that it can be easily connected.
◆ Amplifier should install steadily and make sure all four feet are on the same level.
◆ Keep the amplifier over 15cm's distance to the surrounding walls.
Do not place the machine near heat sources such as radiators, heat registers or other products that
Installation
13
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
problems or shorten the amplifier's life.
NOTE:
Tube Replacement
Tubes for the Machine Tubes Replacement
12AX7/ECC83 12AX7EH、E83CC、ECC803S
12AU7/ECC82 12AU7EH、E82CC、ECC802S
KT88 KT88EH、6550、6550EH、KT66、KT90、KT100
EL34 6CA7、EL34EH、KT77

14
Audio Connection
NOTE:
Please refer to the manuals of other connected equipments during the installation.
Do not insert the power cord into the main socket before all other equipments are well
connected.
R refers to right channel while L represents left channel.
Please take the right guidance for connection as wrong connection may cause noise, low-
grade function or damage.
Do not fasten signal cable together with power cable and speaker cables. It will worsen the
acoustic fidelity.
•
•
•
•
•
Note:
♦ Do not mix up the positive and negative ends of speaker cables or it will cause short circuit.
♦ Please make sure local power supply is at the same level as the rated voltage level indicated on the rear of
the product before connection.
♦ In order not to cause noise, low-grade function or damage, please do not insert the power cord into the
main socket before all other equipments are well connected.
♦ Once switched on there is a period of 35 seconds for pre-heating of the tubes among which there is no
signal output.
♦ Please switch off the amplifier first if you are going to pull off the USB cable .
To audio output terminal
HIFI COMPACT DISC PLAYER
ON OFF
kHz
bit
192
24
MUTE
SOURCE
CDT- AMK2
15 VACUU M TU BE TRANSI ST OR A NALOG O UTPUT
MODEL : CS - 55A
SER.NO. :
VACUUM TUBE INTEGRATED AMPLIFIER
INPUT
CD AUX PHONO
GND
RIGHT OUTPUT LEFT OUTPUT
USB
ZHUHAI SPARK ELECTRONIC EQUIPMENT CO.,LTD.
TUBE SEL.
EL34
KT88
Please take the following picture for your reference of the connection methods of CS-55A amplifier with other
equipments like Computer, cd player and turntable etc.
Connection with the computer: please use the USB cable attached or other USB cable which complies with
USB 2.0 specification to connect the USB Audio input interface and computer.
Wrong connection
Right connection

Speaker Connection
15
Check the impedance of your speakers:
Attach the positive from your speaker to the 4 or 8 ohm terminal and the negative to the 0 ohm terminals
separately. If your speakers are 6 ohm, 4 ohm or 8 ohm (recommended) terminal is preferential and it would not
cause damage to the amplifier.Connecting the left and right speakers according to the guidance can make sure
of the acoustic fidelity.
Connection of speaker cables:
1. Unscrew the terminal knob
2. Insert the speaker cable
3. Screw the terminal knob
Connect the speaker cables with the amplifier after it is
well connected with the speakers.
• Connect both of the speakers to make sure of the
acoustic fidelity.
• Please notice the signal direction indication of the cables.
• Do not mix up the positive and negative ends of speaker
cables or it will cause short circuit.
•
NOTE:
Banana plug Normal plug
MODEL : CS - 55A
SER.NO. :
VACUUM TUBE INTEGRATED AMPLIFIER
INPUT
CD AUX PHONO
GND
RIGHT OUTPUT LEFT OUTPUT
USB
ZHUHAI SPARK ELECTRONIC EQUIPMENT CO.,LTD.
TUBE SEL.
EL34
KT88
RED
BLACK
RED
BLACK
SPEAKER（L）
SPEAKER（R）

16
Turning On
Before turning on the amplifier please make sure all connections are right and power supply is stable.
• Turn on the amplifier, the power indicator will be on and the working indicator will keep flickering.
• The working indicator will be on after 30 seconds. It means that the amplifier is working normally. If the
working indicator is off, please turn off the power and contact with our local agent or our company.
• Select the right audio source channel, adjust the volume to a certain position and then you can enjoy the
music you prefer.
1. When the audio system is under working state, don't
unplug the signal cable or speaker cables, or it will
cause damage to the amplifier and other equipments.
2. It should at least takes 2 minutes before you turn on the
power again, or it will cause damage to the vacuum
tubes.
NOTE:
Read the Manual —— Please read the user's manual carefully before installation and operation.
Keep the Manual —— Please keep the manual for future reference.
Warning Signs —— Don't tear off or rub off the serial number.
Operation —— Do the operations as you are instructed in the Manual.
Parts —— If you are going to use parts not supplied by our company like power cord, fuses etc please make
sure that parts you used are compatible with the safety requirements. Or it will cause fire or electric
shock.
Placement —— Put the amplifier on a level place. Make sure that it doesn't bring damage to the children,
adults and the amplifier itself.
Power —— Please make sure the local voltage is the same level as indicated on the rear panel.
Overload —— If the power socket is overloaded with other equipment, it will cause fire or electric shock.
Warranty Service —— Do not open the product and change the components inside yourself. Opening the
cover may expose you to dangerous voltage or other hazards. The warranty doesn't
extend to any product that has been opened by you without permission of our
company.
Troubleshooting —— If any problems when you are using the product, please check according to following
tips to look for the exact reason. Please contact with our company if you can't solve
the problem.
Small T i ps

17
Please follow the instruction in the manual in order to keep the amplifier work in its best state. If wrongly
operated and you thought that would be troubles please check according to following tips to look for the exact
reasons.
Troubleshooting
NOTE: is the registered trademark of Zhuhai Spark Electronic Equipment Co., Ltd.
Problem Cause Remedy
NO OUTPUT
Power Indicator is
OFF.
Power cord is not well-connected. Check power cable connection or
power outlet connection
Main fuse is out. Replace with the same type
and value fuse.
Troubles of inner parts or components. Please contact with local
agents or our company.
Power Indicator is
ON.
Volume is at ZERO. Turn up the Volume.
NO signal input.
Check the function of the
sound source.
Check the input selection and
switch to the proper input.
Sound Distortion High input signal level. Turn down the volume to
suitable position.
Noise output
Ground of input signal cable is open
or bad contact of the input signal cable.
Replace the input signal
cable with a new one.
Components or circuits are in trouble. Please contact with local
agents or our company.
Sound field Positioning
is not so good.
Signal input cables or speaker
cables are wrongly connected.
Reconnect it as suggested in
the manual.
Malfunction of Remote
Control
Be disturbed. Keep away from the source of
disturbance. Turn off and restore.
Low Battery. Replace with new batteries.
Obstacles between the amplifier and
remote. Remove the obstacles.
Can't lock the USB signal
USB cable is not well connected. Connect the USB cable well
USB Audio Device has not been set. Set USB Audio Device
No USB data Keep the Media Player in working
state
Computer can't recognize
the device
The USB line is not according to the
USB2.0 specification Replace the USB line
USB driver has not been installed Install the USB driver
USB driver error Restart the computer
The sound is abnormal
when the input status is USB
USB socket error Choose another USB socket
Computer is too busy Reduce the running application
program
The hardware resource of computer is
too low
Upgrade the computer if
necessary

18
How to Install Vacuum Tubes
Pin No. 9 Pin No.1
How to Install 9-Pin Vacuum Tubes
12 A U 7 (E C C 8 2 )、 12 A X 7 (E C C 8 3 )
Applicable vacuum tube:
、5B K 7、12BH7、
12AT7(ECC81)、6922（ECC88), etc. 9-Pin vacuum tubes.
Instructions to Change and Install the vacuum tubes:
To install a nine-pin vacuum tube, align the pins of the vacuum
tube with the holes of the tube socket and insert the tube
vertically up and down (as shown in the figure above).
Please note that when installing the nine-pin vacuum
tube, pay attention to the alignment of the vacuum tube
pins with the holes of the tube socket. Otherwise wrong
insertion will cause damage to the vacuum tube and
prevent the amplifier from working properly, which may
lead to failure of the amplifier.
Positioning Pin
How to Install 8-Pin Vacuum Tubes
Applicable vacuum tube:
KT150、KT170、KT88、6550、EL34、6V6、6SN7、6SL7、5AR4,
etc. 8-pin vacuum tubes.
Instructions to Change and Install the vacuum tubes:
To install an eight-pin vacuum tube, align the positioning pin of
the tube with the grooves in the positioning holes of the tube
socket, and install the tube by pulling up and down vertically
(as shown in the figure above).
Please note that when installing the eight-pin vacuum tube,
pay attention to the alignment of the vacuum tube positioning
pin with the positioning hole of the tube socket. Otherwise
wrong insertion will cause damage to the vacuum tube and
prevent the amplifier from working properly, which may lead to
failure of the amplifier.
How to Install 4-Pin Vacuum Tubes
Applicable vacuum tube:
300B、2A3 etc. 4-pin vacuum tubes .
Instructions to Change and Install the vacuum tubes:
To install a four-pin vacuum tube, please pay attention to the
thickness of differnet pins of the vacuum tube and the size of
the tube socket hole. Thick pin should be aligned with the big
hole, and the thin pin should be aligned with the small hole.
Install the tube vertically up and down (as shown in the figure
above).
Please note that when installing the four-pin vacuum tube,
pay attention to the thickness of differnet pins of the vacuum
tube and the size of the tube socket holes. Otherwise wrong
insertion will cause damage to the vacuum tube and prevent
the amplifier from working properly, which may lead to failure
of the amplifier.
Thin Pin Thick Pin
Big Hole
Small Hole
How to Install Big 4-Pin Vacuum Tubes
Applicable vacuum tube:
845、805、211 etc. 4-pin vacuum tubes.
Instructions to Change and Install the vacuum tubes:
To install the big four-pin vacuum tube, align the vacuum tube
positioning pin with positioning pin slot of the tube socket and
then rotate 45° clockwise to tighten. (As shown in the picture
above). To take out the big four-pin vacuum tube, turn the tube
45° counterclockwise and take it out upward after loosening.
Please note that when installing the big four-pin vacuum
tube, pay attention to the alignment of the vacuum tube
positioning pin with positioning pin slot of the tube socket and
then rotate 45° clockwise to tighten. It is strictly forbidden to
install the vacuum tube when the positioning pin is off or
missing. Otherwise wrong insertion will cause damage to the
vacuum tube and prevent the amplifier from working properly,
which may lead to failure of the amplifier.
Positioning Pin
Positioning Pin Slot