VHT Special 12-20 Head User Manual

VHT SPECIAL 12/20

12-20 Watt Hand-Wired Vacuum Tube Guitar Amplier

User Manual

TABLE OF CONTENTS

PRODUCT SAFETY INFORMATION.................1

OVERVIEW.............................................................2

FEATURES.............................................................3

CONTROL PANEL FUNCTIONS.....................4-5

REAR PANEL FUNCTIONS.............................6-7

BLOCK DIAGRAM................................................7

BOOST CONTROL GRAPH................................8

TONE CONTROL GRAPHS..........................9-10

DEPTH CONTROL GRAPH..............................11

TEXTURE SWITCH GRAPH............................12

FX RETURN - DEPTH CONTROL GRAPH...13

FX RETURN -TEXTURE SWITCH GRAPH...14

SCHEMATIC........................................................15

TECHNICAL SPECIFICATIONS......................16

IMPORTANT SAFETY INSTRUCTIONS

1) Read these instructions.

2) Keep these instructions.

3) Heed all warnings.

4) Follow all instructions.

5) Do not use this amplifier near water.

6) Clean only with dry cloth.

7) Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.

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

9) 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.

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

the amplifier.

12) Unplug this amplifier during lightning storms or when unused for long periods of time.

13) Refer all servicing to qualified service personnel. Servicing is required when the amplifier 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 amplifier, the amplifier has been exposed to rain or

moisture, does not operate normally, or has been dropped.

14) The amplifier shall not be exposed to dripping or splashing and no objects filled with liquids, shall be placed on the amplifier.

15) This amplifier shall be connected to a mains socket outlet with a protective earthing/ground connection.

16) The mains/power plug or amplifier coupler is the disconnect device which must remain readily operable.

WARNING To reduce the risk of fire or electric shock, do not expose this amplifier to rain or moisture.

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VHT SPECIAL 12/20

The Pedal-Friendly Amp with Selectable Power Ranges

Building on the success of the popular VHT Special 6 and Special 6 Ultra, the VHT Special 12/20 features increased power (with two power

ranges), a unique preamp specically designed to excel with pedals and multi-eects units, a convenient built-in 9-volt DC pedal power supply,

an all-tube buered eects loop with send and return level controls, variable Watts control, plus VHT’s unique Depth and Texture controls.

To optimize the amp for a wide range of output tubes, the VHT Special 12/20 oers two output-power ranges; safely located behind the rear

panel, a special voltage range switch provides the proper voltages for 6V6 or EL84 output tubes (in 12-watt low-voltage/low-power mode). The

high voltage 20-watt setting provides the ideal voltages for higher-power 6L6 or EL34 output tubes. The Special 12/20 ships from the factory

with a pair of 6V6 output tubes (VHT 6V6-to-EL84 socket adapters are required for operation with EL84 tubes). In addition, the Special 12/20’s

variable Watts control can reduce the maximum output power to less than one watt for whisper-quiet volume levels.

The Special 12/20 preamp was designed to bring the most out of every eects pedal and multi-eects unit with enhanced clarity, detail, and

controlled tube compression. Its low-impedance buered eects loop send — with variable send level — can eortlessly drive the most dicult

pedals without tone or signal loss. Thanks to its variable send and return level controls, the 12/20’s eects loop can accommodate a wide

range of pedal or rack eects. Those seeking the shortest signal path to the output stage can plug their pedals or multi-eects units directly

into to eects return jack — the 12/20’s unique output stage Depth and Texture controls are post-eects loop, so the output stage characteris-

tics can always be ne-tuned to accommodate a wide range of instruments, speakers, playing styles and environments.

As an added convenience for pedal users, the VHT Special 12/20 also features a built-in, regulated 9-volt DC pedal power supply.

Hear your pedals like never before — with the VHT Special 12/20.

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VHT SPECIAL 12/20 FEATURES

12-20 Watts Maximum Output Power

High/Low Tube Voltage Switch

Two 6V6 Output Tubes

Accepts EL84 Output Tubes*

Also Accepts 6L6 or EL34 Output Tubes

Three 12AX7 Preamp Tubes

Volume and Tone Controls

Footswitchable Boost Mode

Effects Loop Send and Return Level Controls

Tube-Driven Effects Loop

Tube-Driven Preamp Line Out

6-Position Depth Control

3-Position Texture Switch

Pentode/Standby/Triode Switch

Watts Control

9V DC Out Power Supply

12” VHT ChromeBack Speaker, 60-watt, 16 ohm (Combo Only)

Switchable 4, 8, or 16 Ohm Speaker Output

Mod-Friendly Eyelet-Type Board

Hand-wired

*With VHT 6V6-to-EL84 Socket Adapters

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