VHT SPECIAL 12/20 12-20 Watt Hand-Wired Vacuum Tube Guitar Amplifier 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.....................
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.
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 specifically designed to excel with pedals and multi-effects units, a convenient built-in 9-volt DC pedal power supply, an all-tube buffered effects loop with send and return level controls, variable Watts control, plus VHT’s unique Depth and Texture controls.
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 (C
CONTROL PANEL FEATURES 1. Power Switch: This switch turns the amplifier on or off. 2. Pentode/Standby/Triode: The Triode setting reduces the amplifier’s maximum output power to approximately one-half of the Pentode setting. Triode setting produces a richer and smoother tone, with earlier breakup than the Pentode setting. The middle position is Standby mode. 3. Watts Control: The Watts control adjusts the output tube’s operating voltage and maximum output power.
CONTROL PANEL FEATURES CONTINUED 5. Depth Control: This 6-position rotary switch selects the output tube’s low-frequency roll-off point. Set fully clockwise for the deepest lowfrequency extension. Lower settings (counterclockwise) expose more midrange texture and detail; the lowest settings emphasize more presence and bite. The three clockwise settings are voiced for single-coil pickups, and the three counterclockwise settings are voiced for humbucking pickups. 6.
REAR PANEL FEATURES 1 2 3 4 5 6 7 8 1. Footswitch Jack: Plug the Boost footswitch into this jack. NOTE: THE BOOST FOOTSWITCH WILL ONLY FUNCTION WHEN THE VOLUME KNOB IS IN THE PULLED POSITION. 2. 9V DC Out: Plug the included 9V DC power supply cable into this jack to power your 9V DC pedal(s) or pedal board. The light will illuminate at all times when powered on, unless the internal 9V DC fuse has blown. Maximum current draw = 1,000 mA. 3.
REAR PANEL FEATURES CONTINUED 4. Line Out Jack: The preamp Line Out is in parallel with the Effects Loop Send and Return jacks, it can be used to send a tube-buffered lowimpedance (unbalanced) signal to other equipment such as mixing consoles or other amplifiers. Multiple Special 12/20 amplifiers can be linked by connecting the Line Out jack to the Effects Return of the second amplifier.
BOOST — ON/OFF -6 d B r -6 -8 -8 -10 -10 -12 -12 -14 -14 -16 -16 -18 -18 -20 -20 -22 -22 -24 -24 -26 -26 -28 -28 -30 -30 -32 -32 -34 -34 -36 -36 -38 -38 -40 -40 -42 -42 -44 -44 -46 -46 -48 20 50 100 200 500 1k 2k 5k 10k 20k d B r -48 Hz 8
TONE CONTROL — NO BOOST d B r +20 +20 +15 +15 +10 +10 +5 +5 +0 +0 -5 -5 -10 -10 -15 -15 -20 -20 -25 -25 -30 -30 -35 -35 -40 -40 -45 -45 -50 -50 -55 20 -55 50 100 200 500 1k Hz 9 2k 5k 10k 20k d B r
TONE CONTROL — PULL BOOST d B r +20 +20 +15 +15 +10 +10 +5 +5 +0 +0 -5 -5 -10 -10 -15 -15 -20 -20 -25 -25 -30 -30 -35 -35 -40 -40 -45 -45 -50 -50 -55 20 50 100 200 500 1k 2k 5k 10k 20k d B r -55 Hz 10
DEPTH CONTROL — PREAMP INPUT (NO BOOST) d B r +10 +10 +7.5 +7.5 +5 +5 +2.5 +2.5 +0 +0 -2.5 -2.5 -5 -5 -7.5 -7.5 -10 -10 -12.5 -12.5 -15 -15 -17.5 -17.5 -20 -20 -22.5 -22.5 -25 -25 -27.5 -27.5 -30 -30 -32.5 -32.
TEXTURE SWITCH — PREAMP INPUT (NO BOOST) d B r +22 +22 +20 +20 +18 +18 +16 +16 +14 +14 +12 +12 +10 +10 +8 +8 +6 +6 +4 +4 +2 +2 +0 +0 -2 -2 -4 -4 -6 -6 -8 -8 -10 400 500 600 700 800 900 1k 2k 3k 4k 5k 6k 7k 8k 9k 10k 20k d B r -10 Hz 12
DEPTH CONTROL — EFFECTS RETURN INPUT d B r +22 +22 +20 +20 +18 +18 +16 +16 +14 +14 +12 +12 +10 +10 +8 +8 +6 +6 +4 +4 +2 +2 +0 +0 -2 -2 -4 -4 -6 -6 -8 -8 -10 20 50 100 200 500 1k Hz 13 2k 5k 10k 20k -10 d B r
TEXTURE SWITCH — EFFECTS RETURN INPUT +8.5 +8.5 d B r +8 +8 +7.5 +7.5 +7 +7 +6.5 +6.5 +6 +6 +5.5 +5.5 +5 +5 +4.5 +4.5 +4 +4 +3.5 +3.5 +3 +3 +2.5 +2.5 +2 +2 +1.5 +1.5 +1 +1 +0.5 +0.5 +0 +0 -0.5 -0.5 -1 -1 -1.5 -1.
VOLUME INPUT Push = Closed (Clean) Pull = Open (Boost) 277V DC a R66 DEPTH 2P-6T ROTARY SWITCH 470K 355 27 315 27 225 SLOW BLOW EL34/6V6GTW D 75 65 Test Conditions: 1. Watts and Depth to Max 2. Tone to Center 3. Volume to Max 4. Sensitivity: 30mV 1kHz Input = 10V Out 5.
TECHNICAL SPECIFICATIONS Name/Model: Power Requirements & Consumption: VHT Special 12/20 — 12-20 watt hand-wired vacuum tube guitar amplifier Maximum Output Power: 12-20 watts (depending on output tube type and Volt setting) Speaker (combo only): One 12” VHT ChromeBack (60-watts, 16 ohms) Amp Type: 100/115VAC, 50/60Hz; 120VAC, 60Hz; 220VAC/230VAC240/VAC, 50/60Hz All-tube hand-wired push/pull cathode biased output stage Tubes: Three 12AX7; two 6V6 Controls: Input,
LIMITED WARRANTY INFORMATION This amplifier is warranted, to the original Purchaser, to be free from defects in material and workmanship for a period of five (5) years, excluding the tubes and speaker, which are warranted for ninety (90) days, from the original date of purchase. The manufacturer shall, at its option, either repair or replace the defective product if the product is returned to the original place of purchase.
