VTL ST-150 User manual

VTL
ST-150 Stereo Power Amplifier
Owner’sManual

MAKING TUBES USER FRIENDLY
VTL ST-150 Stereo Power Amplifier
Information in this document is subject to change without notice. No part of this document may be reproduced or transmitted
in any form or by any means, electronic or mechanical, for any purpose, without the express written permission by VTL.
Version History:
Version 5.1: January , 2010
Copyright ©2010 by VTL Amplifiers Inc. All rights reserved.
4774 Murrieta Street, Suite 10
Chino, CA 91710, USA
Phone [phone] • Fax [phone]
http://www.vtl.com/
Email: [email protected]
Part Number OM-0010-601

Table of Contents
CHAPTER 1 .......................................................................................................................................1
INTRODUCTION....................................................................................................1
Symbol Conventions used in this guide..................................................................................1
Electrical Safety Notice...........................................................................................1
Water and Moisture...................................................................................................1
Location and Ventilation........................................................................................1
Servicing...........................................................................................................................2
Operational Warnings.............................................................................................2
CHAPTER 2 .......................................................................................................................................3
GETTING STARTED.........................................................................................3
Unpacking the ST-150 from its box..................................................................3
The ST-150 Front Panel.........................................................................................4
Check for tube placement.......................................................................................................4
ST-150 Back Panel.................................................................................................................5
Connecting Your Amplifier to your system..................................................5
Voltage Setting.............................................................................................................6
Power Source for your Amplifier......................................................................6
CHAPTER 3 .......................................................................................................................................7
OPERATING THE AMPLIFIER..............................................................7
Powering your system on.......................................................................................7
Ground Loop Hum.....................................................................................................7
Powering the system off..........................................................................................8
Tetrode-Triode Switching......................................................................................8
Bias checking and Setting......................................................................................8
Top view and Bias Measurement points of the ST-150 Amplifier...................................................10
CHAPTER 4 .....................................................................................................................................11
CARE AND MAINTENANCE OF YOUR VTL
AMPLIFIER...............................................................................................................11
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BREAK IN PERIOD..........................................................................................11
Power-on Period.......................................................................................................11
Tube Types....................................................................................................................11
Tube Life........................................................................................................................11
Changing Tubes...................................................................................................................12
Changing the AC and B+ Fuses......................................................................13
Cleaning.........................................................................................................................13
Transporting ST-150...............................................................................................13
CHAPTER 5 .....................................................................................................................................14
SPECIFICATIONS...............................................................................................14
CHAPTER 6 .....................................................................................................................................15
WARRANTY..............................................................................................................................15
APPENDIX.......................................................................................................................................16
Warranty Registration...........................................................................................16
Service Notes...............................................................................................................16
ST-150 Owner’s Manual
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CHAPTER 1
Introduction
Congratulations on your purchase of the VTL ST-150 Stereo Power Amplifier.
he ST-150 Stereo Amplifier, a 150 watts per channel amplifier, is designed to deliver an involving and
true-to-live listening experience to you. Proper care and maintenance of the ST-150 will assure its
lasting value and maximum performance. Please take a moment to read through this owner’s manual
and please take time to get familiar with the features of this product, so that you can become familiar
with the operating and maintenance procedures needed for the ST-150. After you have finished reading this
manual please keep it in a safe place for future reference.
T
The VTL team is proud that you have selected the ST-150 power amplifiers as a new member of your home
audio and home theater system. We sincerely hope that the VTL ST-150 will contribute towards your
enjoyment of music and give you many hours of listening pleasure.
Symbol Conventions used in this guide
Certain symbols are used in this owner’s manual to draw your attention to important points being discussed.
For your own safety and that of your equipment you should note and heed the warnings that follow these
symbols.
The “Warning - Pay particular Attention” symbol used is
And the “Warning - Observe These Precautions for Your Safety” is
Electrical Safety Notice
Electrical voltage from power cables is hazardous. We recommend that the power cord connected to this unit
be used with a properly grounded outlet. To prevent electrical shocks do not remove any of the covers from
this amplifier, especially while the unit is powered on.
Water and Moisture
The amplifier should not be used close to any water or moisture sources. If liquid enters the amplifier it must
be immediately unplugged and returned to your dealer for servicing. If this occurs you should under no
circumstances try to power the unit on before the unit has been properly serviced by a trained repair technician
- there are hazardous voltages present in this unit that can cause serious injury if they come in contact with you.
Location and Ventilation
Install this amplifier in a location that is stable and well ventilated. If the amplifier is placed in a built-in
installation, ensure that there is adequate room for a supply of air to flow through the ventilation openings.
Allow at least 9 inches clearance on the top and around the sides of the amplifier. Be sure the amplifier is at
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least 10 inches away from your preamplifier to prevent possible noise introduction into your system. Tiptoes
or other isolation accessories may prove useful in reducing mechanical vibrations. Do not place amplifiers
directly on high pile carpets, as this will block the ventilation vents. Do not place the amplifier next to
heat sources such as radiators, stoves or other appliances. Do not place amplifier on the floor where small
children can tamper with the equipment. If it is not possible to place amplifier out of the reach of small
children it is recommended that you remove power cables when the equipment is not in use.
Servicing
Do not attempt to service the amplifier beyond the procedures described in this manual. For all other service
and questions, please contact your authorized VTL dealer or the factory.
Operational Warnings
ÎDo not touch the tubes after the amplifier is turned on. Tubes can get very hot while the
amplifiers are operating. Turn off the amplifier and allow the tubes to cool down before attempting to work
with the tubes.
ÎDo not attempt to disassemble the amplifier chassis or remove any covers from the amplifier.
Always consult with your VTL authorized dealer or the VTL factory support department before attempting
any service work on any VTL unit.
ÎAlways connect your loudspeaker to the amplifier before powering the unit on. Operating any VTL
power amplifiers without a speaker load connected can damage the output transformer, and will not be
covered under the warranty. Also, ensure that no speaker cables can become loose during use and that there
are no intermittent faults with the cables.
ÎTube amplifiers can be heavy and awkward to lift, with the weight unevenly distributed, and you
should not attempt to move the unit without help. Each unit of the ST-150 Stereo weighs approximately 58
lbs. (26.4 Kg).
ÎDo not attempt to make or break any connections to the amplifier while the unit is powered on as
this can damage the amplifier and/or the rest of the system, and this damage is not covered by warranty.
ÎIf this unit has tetrode/triode switch, do not flip the triode tetrode switches while the unit is powered
on, as this can damage the switch and is not covered under warranty.
ÎDo not exceed fuse ratings or attempt to bypass any fuses, as this can cause an extremely hazardous
condition and will void any warrantees. Use only the same type and rating of fuses as specified in the owner’s
manual and marked on the unit.
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CHAPTER 2
Getting Started
Unpacking the ST-150 from its box
The ST-150 Stereo amplifiers are shipped in cartons and wrapped in thick plastic. The plastic is not strong
enough to support the unit, and may tear if you try to lift the unit out of the box with it. Also there are
protruding switches which could break if the unit is not properly handled, and in addition to the awkward,
unbalanced heavy load the unit has a cleaning polish on it which makes it slippery and hard to grasp. We have
found that the best way to remove the amplifier from the box is as follows:
1. With the box on a thick carpeted floor, fold back all the flaps of the top of the carton, leaving all
the packing foam in place. Roll the carton onto one long side on top of the flap.
2. Roll the box once more onto the open top and, making sure that none of the flaps is trapped
under the carton, the unit should now be upside down, lift the carton off the unit.
3. Lift the top foam away from the upside down unit and carefully cut away the plastic from around
the amplifier.
4. Lift the amplifier up by rolling the unit onto a short side and then again so that it lands on its
four rubber feet. Then lift away the packaging and set all the packaging in the carton.
5. When lifting the unit be sure to only lift it from the bottom under the transformers. Be careful
not to break any switches. Be sure to only set the amplifier down on its bottom side on the four
rubber feet on a stable surface. Setting it on any other side may damage protruding components.
If the unit is too heavy or too awkward to lift then do not attempt to do this by yourself, but rather
find someone to help you. Save the carton and all packaging for any future shipment of the amplifiers.
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The ST-150 Front Panel
The ST-150 Front Panel shows the Power on switch and the power on LED indicator.
Check for tube placement
Use the following procedures to check whether the tubes standing on the deck of your amplifier are placed
firmly in their sockets, as the tubes can become dislodged and loosen during shipping or unpacking of the
amplifier.
Visually inspect through the vent holes to ensure that all tubes are fully seated before
powering the unit on for the first time. If there are any tubes not fully seated then you
should refer to your VTL dealer, and take this procedure with the amplifier.
Notes for the servicing technician:
1. Remove the protective wire cage on the top deck of the amplifier. The
cage is mounted with three screws on each side of the amplifier as well as 2
hex screws on the top portion of the front panel. Use a 7/64” hex wrench
to remove the hex screws from the top of the front panel. Loosen the side
screws and lift the wire cage slowly and carefully. Do not let the cage
touch or hit any of the tubes inside the amplifier. Keep the cage and the
screws in a separate place while you’re working on the amplifier.
2. Make sure that the amplifier is not connected to the power outlet and not
turned on. Use your fingers to hold onto the upper portion of the tube towards its tip. Gently
rock the side of the tube to see if there is any movement in the tube. If there is any movement,
that means the tube has come loose. Press the tube firmly into its socket, using a gentle force
and a slight “rocking” motion.
3. Repeat the above test for the rest of the tubes. There are a total of eight output tubes and four
input tubes in each amplifier.
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4. After you’ve examined all the tubes to make sure that they are firmly placed in their sockets, you
can put the protective cage back onto the amplifier unit. Tighten the screws to make sure that
the cage is securely fastened to the unit.
ST-150 Back Panel
TETRODE
SPEAKER
RIGHT CHANNEL
8A(120VAC) SLO-BLO
MAIN FUSE
4A(240VAC) SLO-BLO
TRIODE
+-
SPEAKER
LEFT CHANNEL
Manufactured by:
Vacuum Tube Logic
4774 Murrieta Street
Suite 10, Chino, CA
91710, USA [phone]
TRIODE
TETRODE
+-
Binding posts
B+ fuse
1A F 600V
RCA input
AC receptacle
AC POWER
INPUT
INPUT
Triode/Tetrode switch
WARNING
To prevent possible switch damage do not change mode
while amplifier is powered on. on before making all connections.or speaker damage do not power To prevent possible transformer
To prevent electrical shock do not remove cover.
No user servicable parts inside. Refer servicing
to qualified personnel. For continued protection
against fire hazard replace only with fuses of same
type and rating. To prevent fire or shock do not
expose this appliance to rain or moisture.
Stereo Power Amplifier
F
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S
U
F
E
S
U
F
E
S
U
F
E
S
U
F
E
S
U
F
E
S
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B+ FUSEB+ FUSE
RCA input
B+ fuse
1A F 600V
1A F 600V 1A F 600V
Triode/Tetrode switch Binding posts
Mains fuse
12A(120VAC) SLO BLO
6A(240VAC) SLO BLO
The ST-150 Back Panel Silkscreen
Connecting Your Amplifier to your system
The ST-150 Stereo amplifier is a self-contained unit with the amplifier and power supply sections on one
compact chassis. Follow the instructions below to connect the amplifier to your audio or home theater
system:
1. Connect all source components (e.g. CD, Tuner, Tape, DAT, Turntable etc.) to the preamplifier.
Follow the instructions on your preamplifier and source component manuals to connect these
components together.
2. Connect the power amplifier to the output channel of the preamplifier. The interconnect cable
between the amplifier and the preamplifier links the input channel of the power amplifier to the output
channel of the preamplifier. Connect the Left Channel RCA Jack from the Stereo amplifier to the left
output channel of the preamplifier. The same applies to the right channel of the amplifier.
3. Select the input connector type. The amplifier supports only one type of input connector – the RCA
input. Place the interconnect cable firmly into the input jack which matches the type you have, and firmly
insert the interconnect cable into the input jack marked “INPUT”.
4. Connect the loudspeaker cable to your amplifier. There is a pair of speaker binding posts in the back
of your amplifier for connecting your loudspeaker cables to the amplifier. These binding posts are marked
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