VTL ST-150, ST-85 User Manual

VTL
ST-150 Stereo Power Amplifier

Owner’s Manual

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: [e-mail]

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

MPLIFIER...............................................................................................................11

A

ST-150 Owner’s Manual
VTL

i

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
VTL

ii

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

T

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.

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.

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

Symbol Conv entions 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 V entilation

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

ST-150 Owner’s Manual
VTL

1

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

Î Do 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.

Î Do 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.

Î Always 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.

Î Tube 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).

Î Do 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.

Î If 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.

Î Do 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.

ST-150 Owner’s Manual
VTL

2