Vox VT15 User Manual

E 1

IMPORTANT SAFETY INSTRUCTIONS

• Read these instructions.

•Keep these instructions.

• Heed all warnings.

•Follow all instructions.

• Do not use this apparatus near water.

• Mains powered apparatus shall not be exposed to dripping or
splashing and that no objects filled with liquids, such as vases, shall
be placed on the apparatus.

• Clean only with dry cloth.

• Do not block any ventilation openings. Install in accordance with the
manufacturer's instructions.

• Do not install near any heat sources such as radiators, heat
registers, stoves, or other apparatus (including amplifiers) that
produce heat.

• Do not defeat the safety purpose of the polarized or grounding-type
plug. A polarized plug has two blades with one wider than the other.
A grounding type plug has two blades and a third grounding prong.
The wide blade or the third prong are provided for your safety. If the
provided plug does not fit into your outlet, consult an electrician for
replacement of the obsolete outlet. (for USA and Canada)

• Protect the power cord from being walked on or pinched particularly
at plugs, convenience receptacles, and the point where they exit
from the apparatus.

• Only use attachments/accessories specified by the manufacturer.

• Unplug this apparatus during lightning storms or when unused for
long periods of time.

•Turning off the power switch does not completely isolate this product
from the power line so remove the plug from the socket if not using it
for extended periods of time.

• Install this product near the wall socket and keep the power plug
easily accessible.

•WARNING—This apparatus shall be connected to a mains socket
outlet with a protective earthing connection.

• Refer all servicing to qualified service personnel. Servicing is
required when the apparatus has been damaged in any way, such
as power-supply cord or plug is damaged, liquid has been spilled or
objects have fallen into the apparatus, the apparatus has been
exposed to rain or moisture, does not operate normally, or has been
dropped.

• Do not install this equipment on the far position from wall outlet and/
or convenience receptacle.

• Do not install this equipment in a confined space such as a box for
the conveyance or similar unit.

• Excessive sound pressure from earphones and headphones can
cause hearing loss.

• Use only with the cart, stand, tripod, bracket, or table specified by
the manufacturer, or sold with the apparatus. When a cart is used,
use caution when moving the cart/apparatus combination to avoid
injury from tip-over.

The lightning flash with arrowhead symbol
within an equilateral triangle, is intended
to alert the user to the presence of
uninsulated "dangerous voltage" within
the product's enclosure that may be of
sufficient magnitude to constitute a risk of
electric shock to persons.

The exclamation point within an
equilateral triangle is intended to alert the
user to the presence of important
operating and maintenance (servicing)
instructions in the literature accompanying
the product.

CAUTION

Danger of explosion if battery is incorrectly replaced.
Replace only with the same or equivalent type.

THE FCC REGULATION WARNING (for USA)

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, uses, and
can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, 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.

•I

ncrease the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different
from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician
for help.

Unauthorized changes or modification to this system can
void the user’s authority to operate this equipment.

Notice regarding disposal (for EU)

If this “crossed-out wheeled bin” symbol is
shown on the product or in the operating
manual, you must dispose of the product in an
appropriate way. Do not dispose of this product
along with your household trash. By disposing

of this product correctly, you can avoid
environmental harm or health risk. The correct method of
disposal will depend on your locality, so please contact the
appropriate local authorities for details.

* All product names and company names are the trademarks

or registered trademarks of their respective owners.

Table of Contents

Introduction .........................................................................4

Welcome! ........................................................................................................ 4

Main features .................................................................................................. 4

Signal path ...................................................................................................... 5

What is Valve Reactor technology? ................................................................ 5

Quick start ..........................................................................6

Setup .............................................................................................................. 6

Checking out the preset programs.................................................................. 7

Switching between the user programs............................................................ 7

Top and rear panels .............................................................8

A. Top panel .................................................................................................... 8

B. Rear panel ................................................................................................ 11

About the three operating modes........................................12

Preset mode (recalling preset programs) ..................................................... 12

Manual mode ................................................................................................ 12

Channel Select mode (recalling user programs) .......................................... 13

Creating and saving sounds ...............................................14

Creating a sound .......................................................................................... 14

Adjusting the noise reduction ....................................................................... 15

Saving a program ......................................................................................... 15

Checking the original values saved in a program ......................................... 16

Restoring the factory settings ....................................................................... 16

Using a foot switch (VOX VFS5) ..........................................17

Foot switch operations in Channel Select mode ........................................... 17

Foot switch operations in Preset or Manual modes ...................................... 17

Explanation of the amps and effects....................................18

Amp models .................................................................................................. 18

Effects ........................................................................................................... 21

Reverb .......................................................................................................... 23

Troubleshooting .................................................................24

Specifications ....................................................................25

Song program list ..............................................................26

Program sheet ...................................................................27

3

Introduction

Welcome!

Thank you for purchasing the VOX VT15 or VT30 Valvetronix amp.

To help you get the most out of your new amplifire, please read this manual care­fully.

Get ready to enjoy the VT15/30’s amazing guitar sounds!

Main features

❒ The VT15 and VT30 use Valve Reactor technology, and feature a power amp circuit

containing a 12AX7 (ECC83) dual triode valve (“vacuum tube”) that would nor­mally be used in a preamp. This allows the amp to produce the true sound and feel
of a bona fide all valve (tube) amp.

❒ Sophisticated modeling technology is used to provide twenty-two different amps.

❒ Twelve high-quality effects are built-in. Of these, reverb is available at all times, and

three of the remaining eleven effects are “multiple effects” that allow you to use up
to three effects simultaneously. Noise reduction can also be used simultaneously.

❒ You can create a sound using the desired amp and effect, and save it in memory as

one of eight programs (two banks x four channels). Programs can be switched while
you perform, either from the top panel or from a foot switch connected to the rear
panel (Channel Select mode). For each amp model, three preset programs – Basic
Effected, and Song – are provided, giving you a total of 66 programs (Preset mode).
The song programs reproduce the tones of classic hits played by famous guitarists.

❒ Manual mode lets you use the VT15/30 as a conventional guitar amp. The physical

positions of the actual knobs will be reflected by the sound.

❒ An optional VOX VFS5 foot switch (sold separately) can be connected, allowing you

to switch programs or turn effects on/off with your feet.

❒ The power level control lets you adjust the output wattage of the power amp. Even

with the master volume set to the maximum so that the Valve Reactor power amp is
loaded, you’ll still be able to adjust the volume without impairing the tonal charac­ter.

4

Signal path

Your guitar sound passes through the following sections.

Refer to “Top and rear panels” (p.8) in conjunction with this illustration.

VOLUME

PRE AMP

Select one

of 22

EFFECT

MODULATION

/DELAY

EFFECT

COMP

/OCTAVE

GAIN

VT15/30 Signal route

What is Valve Reactor technology?

The Valve Reactor circuit used in the power amp of this VT15/30 combo amp is based
on new technology. Most of the sound creation and tonal shaping is performed in the
digital domain, but the Valve Reactor power amp is 100% analog. Passing the guitar
signal through the analog-domain power amp stage is an important factor in capturing
the feel and tone of the original amp for that model.
Valve Reactor’s power stage is a miniature version of a true tube push/pull power
amp. It uses a 12AX7 tube (dual triode; in other words, two vacuum tubes in one), and
is similar to a true tube amp with an output transformer. Rather than connecting the
vacuum tube directly to a speaker via an output transformer, the signal is converted by
a virtual output transformer in which solid stage components emulate the output trans­former, and the final output stage circuit is connected to a specially designed VariAmp
power circuit. This allows the output of the power stage to be continuously varied
from minimum output to maximum output.
This VariAmp power circuit is completely transparent – i.e., it does not modify the
signal – so the output tone will be the pure sound of a tube amp. The wide dynamic
range seen in a conventional tube amp is also maintained. This dynamic range is a
characteristic that is difficult to obtain from a solid-state amp; this is why a tube amp
sounds more powerful than a solid-stage amp of the same output specifications. The
output of the Valve Reactor power amp “reads” the constantly changing impedance
curve of the connected speaker system, and feeds this information back to the vacuum
tube. In response to this information, the operation of the amp’s tube stage will vary
according to the speaker load (impedance). This too is an important element in the
sound of a true tube amp. In addition to producing lively tube sound, “circuitry char­acteristics” distinctive of the full-tube power stage in the amp being modeled can also
be simulated. These characteristics include class-A, class-AB, and power output. By
adjusting these characteristics (except for the power output, which the user specifies),
every sound of that amp model can be faithfully reproduced. This power amp technol­ogy, for which a U.S. patent has been obtained, is unique to the VOX Valvetronix amps.

REVERB

MASTER

VA LVE REACTOR

VALV E

ECC83 (12AX7)

CLASS A or AB

FEEDBACK CIRCUIT

Circuit is determined
by Pre Amp selection

POWER LEVEL

5

Quick start

This Quick Start section is for those of you who would like to start using your new
amp right away.

This manual contains information that will help you take full advantage of your
Valvetronix amp, so be sure to read the rest of it after you’ve read the Quick Start
section.

Setup

1. Set the VT15/30’s [MASTER] volume to the minimum level.

2. Connect the included power cable to the rear panel AC power connector, and plug

the other end into an AC outlet.

3. Plug the cable connected to your guitar into the top panel INPUT jack.

HINT: Illustrations of the top panel and rear panel are provided in “Top and
rear panels” (p.8), so refer to them as you try out your amp.

4. Turn on the [POWER] switch.

5. Slowly raise the [MASTER] volume to adjust the volume.

HINT: The rear panel [POWER LEVEL] control adjusts the output level of
the power amp. This lets you adjust the volume while preserving the dis­tortion of the power amp.

NOTE: There may be no sound for several seconds until the vacuum tube
warms up. This is not a malfunction.

6

Checking out the preset programs

1. Press the top panel [PRESET] switch.

The PRESET LED will light up(Preset mode).

2. Turn the [AMP] selector to select an amp model.

A preset program for a sound that is typical of each amp model will be recalled, and
the GAIN, VOLUME, TREBLE, MIDDLE, BASS, and effect settings will switch auto­matically.

HINT: The amp models are organized into two banks, each bank contain­ing eleven models (a total of twenty-two). Press the AMP switch to change
banks. Each time you press this, the AMP LED will change to green or red,
and you’ll alternate between amp banks A and B. Each of the twenty-two
amp models has three preset programs (a total of sixty-six programs). In
Preset mode, pressing the [PRESET] switch will cycle the PRESET LED be­tween green, orange, and red, switching between preset programs 1 (basic),
2 (effected), and 3 (song).
Each song program reproduces the tone of a hit played by a famous guitar­ist.

Switching between the user programs

1. Press one of the top panel [CHANNEL] switches ([CH1], [CH2], [CH3], or [CH4]).

The LED of the [CHANNEL] switch you pressed will light, and the user program
specified for that channel will be recalled (Channel Select mode).

HINT: The user programs are organized into two banks, each bank contain­ing four channels (a total of eight programs). Press the [CHANNEL BANK]
switch to switch banks. Each time you press it, the BANK LED will change
between green and red, switching between channel banks 1 and 2.

HINT: You can store your own favorite sounds in a program. For details,
refer to “Saving a program” (p.15).

7

Top and rear panels

In this chapter we're going to take a look at the top and rear panels of your Valvetronix
amp.

A. Top panel

2

The illustration shows the VT15.

1

4

3

5

1. INPUT/PHONES section

INPUT jack

This is where you plug in your guitar.

PHONES jack

Use this jack if you want to output directly to a mixer or recording device, or when
you want to use headphones. The signal that is output from this jack is taken from
directly before the Valve Reactor power amp, and the cabinet response of the guitar
amp will be applied to it.

NOTE: If you connect this jack, no sound will be output from the internal
speaker.

2. Amp section

Here you can make settings for the amp. The “chicken head” type knobs reflect the
tradition of VOX amplifiers.

[AMP] switch/selector, LED

Here you can select the amp mode.
Each time you press the [AMP] switch, the AMP LED will change color between
green and red, switching between amp banks A and B. Use the [AMP] selector to
choose a model within the selected amp bank.
The operation of the pre-amp, power amp (class A or AB), the response of the tone
controls and their location within the circuit are all switched according to the amp
model you select here, causing each of these to behave as they do in the original amp.

8

In Preset mode (i.e., when the PRESET LED is lit), you can recall preset programs
that contain sounds and effect settings that are typical of each amp model.

[GAIN] control

This adjusts the pre-amp gain of the selected amp model.

[VOLUME] control

This adjusts the volume of the selected amp model.

[TREBLE], [MIDDLE], [BASS] controls

These adjust the tone for the high, mid, and low-frequency ranges. The change pro­duced by each control will differ depending on the amp model that you’ve selected.

[REVERB] control

This adjusts the mix amount for the reverb.

[MASTER] volume

This adjusts the volume that is output from the pre-amp to the Valve Reactor power
amp. This setting will change the amount of the Valve Reactor’s distortion.

NOTE: The [MASTER] volume setting is not programmed.

NOTE: The amount of Valve Reactor distortion is also affected by the GAIN

control. For some settings, there will be almost no distortion.

3. Effect section

Here you can make settings for effects and noise reduction. For details on each effect,
refer to “Explanation of the amps and effects” (p.18).

[EFFECTS] selector

This selects the effect type. You can use the [TAP] switch and [EDIT] knob to adjust
the parameters of each effect. When you switch the effect type, the parameter set­tings of the effect will be initialized, and Effect Bypass will be disabled.

[EDIT] knob

This adjusts the parameters of each effect. The knob can adjust three different param­eters when used in conjunction with the [TAP] or [BYPASS] switches as described
below (when the BYPASS LED is unlit).

- EDIT 1: Turn the [EDIT] knob (without holding down a switch).

- EDIT 2: Turn the [EDIT] knob while holding down the [TAP] switch.

- EDIT 3: Turn the [EDIT] knob while holding down the [BYPASS] switch.

When the BYPASS LED is lit (i.e., when the effect is bypassed), you can adjust the
sensitivity of the noise reduction by holding down the [TAP] switch and turning the
[EDIT] knob.

NOTE: You can’t adjust effect parameters while the BYPASS LED is lit.

9