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VHT SPECIAL 12/20RT

THE PEDAL-FRIENDLY AMP WITH SELECTABLE POWER RANGES

 PLUS ALL-TUBE SPRING REVERB AND TREMOLO

The VHT Special 12/20RT adds tube-driven spring reverb and tube tremolo to the pedal-friendly Special 12/20 platform. Like 
the Special 12/20, the 12/20RT features a unique preamp specifically designed to excel with pedals and multi-effects units, 
with a pedal-friendly all-tube buffered effects loop with send and return level controls. And like the 12/20, the 12/20RT also 
accepts a wide range of output tube types, with two power ranges complemented by an adjustable Watts control and a Pen-
tode/Triode switch. The Special 12/20RT also features VHT’s unique Depth and Texture controls, a convenient built-in 9-volt 
DC pedal power supply, and an international mains voltage selector switch. 

Like the Special 12/20, the Special 12/20RT’s preamp was designed to bring the most out of every effects pedal and multi-
effects unit with enhanced clarity, detail, and controlled tube compression. Its low-impedance buffered effects-loop send can 
effortlessly drive the most difficult pedals without tone or signal loss. Thanks to its variable send and return level controls, 
the 12/20RT’s effects loop can accommodate a wide range of pedal, multi-effects units and rack effects. The 12/20RT’s Re-
verb, Tremolo, Depth and Texture controls are post effects loop, so multi-effects users can plug directly into the effect return 
and still benefit from the post-effects tube reverb and tremolo, while also fine-tuning the output stage characteristics with 
the Depth and Texture controls. 

To optimize the amp for a wide variety of output tubes, the VHT Special 12/20RT offers 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 12/20RT ships with a pair of 6V6 output tubes (VHT 6V6-to-EL84 socket adapters are 
required for operation with EL84 tubes). In addition, the Special 12/20RT’s variable Watts control can reduce the maximum 
output power to less than one watt for whisper-quiet volume levels.

VHT — THE WORLD LEADER IN AFFORDABLE HANDWIRED AMPLIFICATION

VHT SPECIAL 12/20RT FEATURES

Special Pedal-Friendly Preamp Design 
Tube-Driven Effects Loop with Line Out Jack
Effects Send and Return Level Controls
9-Volt DC Pedal Power Supply
6V6 Tube-Driven Spring Reverb with Deep Switch
Tube Tremolo with Slow/Fast Range Switch
Switchable 12/20 Max Output 
Variable Watts Control
Pentode/Triode Switch
6-Position Depth Control
3-Position Texture Switch
Footswitchable Push/Pull Boost
Switchable 4, 8 or 16 Ohm Speaker Outputs
International Voltage Switch
Four 12AX7 Tubes
One 6V6 Reverb Driver Tube
Two 6V6 Output Tubes
Accepts EL84 Output Tubes*
Also accepts 6L6 or EL34 Output Tubes
Mod-Friendly Handwired Eyelet-Board Construction
2-Button Reverb/Tremolo Footswitch (Included)
1-Button Boost Footswitch (Included)
12” VHT ChromeBack Speaker, 60-watt, 16 ohm (Combo Only)

*With VHT 6V6-to-EL84 Socket Adapters

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Summary of Contents for Special 12

Page 1: ...12 20 Watt Hand Wired Vacuum Tube Guitar Amplifier User Manual VHT SPECIAL 12 20RT...

Page 2: ...plug 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 a...

Page 3: ...and tremolo while also fine tuning the output stage characteristics with the Depth and Texture controls To optimize the amp for a wide variety of output tubes the VHT Special 12 20RT offers two output...

Page 4: ...Reverb Tremolo footswitch 11 Pull Deep Pull this knob to add more low end depth to the reverb signal 12 Tone Control This control adjusts the balance of the high and low frequencies 13 Volume Control...

Page 5: ...d amplifier Several Special series amplifiers can be linked in this manner with the first amplifier s pre amp serving as the master preamp for all additional amplifiers 5 Impedance Selector This 3 pos...

Page 6: ...5 d B r 20 20k 50 100 200 500 1k 2k 5k 10k Hz 55 20 50 45 40 35 30 25 20 15 10 5 0 5 10 15 d B r TONE CONTROL PULL BOOST 55 20 50 45 40 35 30 25 20 15 10 5 0 5 10 15 d B r 20 20k 50 100 200 500 1k 2k...

Page 7: ...0 20k 50 100 200 500 1k 2k 5k 10k Hz 32 5 10 30 27 5 25 22 5 20 17 5 15 12 5 10 7 5 5 2 5 0 2 5 5 7 5 d B r TEXTURE SWITCH PREAMP INPUT NO BOOST 10 22 8 6 4 2 0 2 4 6 8 10 12 14 16 18 20 d B r 400 20k...

Page 8: ...2k 5k 10k Hz 10 22 8 6 4 2 0 2 4 6 8 10 12 14 16 18 20 d B r TEXTURE SWITCH EFFECTS RETURN INPUT 2 8 5 1 5 1 0 5 0 0 5 1 1 5 2 2 5 3 3 5 4 4 5 5 5 5 6 6 5 7 7 5 8 d B r 400 20k 500 600 700 800 900 1k...

Page 9: ...Reverb Driver Pull Deep Reverb Reverb Return Spring Tremolo Fast Slow 6V6 6V6 6V6 12AX7 12AX7 12AX7 12AX7 12AX7 12AX7 12AX7 12AX7 Speed Tremolo BLOCK DIAGRAM 48 6 46 44 42 40 38 36 34 32 30 28 26 24...

Page 10: ...A STB ON ON S3B S3C STBY TRIODE PENTODE 4 5 4 5 2 2 7 7 9 9 6 8V 12V C56 470u 16V T T NC JK1 9V DC OUT R73 100R R74 100R R72 220R D10 LED RED D5 1N4007 D6 1N4007 D8 1N4007 D7 1N4007 OUT G IN U1 7809 R...

Page 11: ...transferable by the Purchaser The warranty shall not apply to wearable parts these items include but are not limited to amplifier knobs feet and handles The warranty shall not apply if the product has...

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