VHT SPECIAL 12/20RT 12-20 Watt Hand-Wired Vacuum Tube Guitar Amplifier User Manual
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 12/20RT 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.
CONTROL PANEL FEATURES 6 CONTROL PANEL FEATURES CONTINUED 8 SLOW/FAST DEEP 1 2 3 4 5 7 9 10 11 12 13 14 15 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.
REAR PANEL FEATURES REAR PANEL FEATURES CONTINUED 1. Foot Switch Jacks: Plug the 1-button Boost footswitch into the lower jack. Plug the 2-button reverb/Tremolo footswitch into the upper button. NOTE: THE BOOST FOOTSWITCH WILL ONLY FUNCTION WHEN THE VOLUME KNOB IS IN THE PULLED POSITION. 1 2 3 4 5 7 6 6L6, EL34 HIGH VOLT 12AX7 12AX7 6V6 12AX7 12AX7 6V6 6V6 Internal Speaker 16 ohms 6V6, EL84 LOW VOLT 8 5 2.
TONE CONTROL — NO BOOST d B r TONE CONTROL — PULL BOOST +20 +20 +20 +20 +15 +15 +15 +15 +10 +10 +10 +10 +5 +5 +5 +5 +0 +0 +0 +0 -5 -5 -5 -5 -10 -10 -10 -10 -15 -15 -15 -15 -20 -20 -20 -20 -25 -25 -25 -25 -30 -30 -30 -30 -35 -35 -35 -35 -40 -40 -45 -45 -40 -40 -50 -50 -45 -45 -50 -50 -55 20 -55 50 100 200 500 1k Hz 7 2k 5k 10k 20k d B r d B r -55 20 50 100 200 500 1k 2k 5k 10k 20k d B r -55 Hz 8
DEPTH CONTROL — PREAMP INPUT (NO BOOST) TEXTURE SWITCH — PREAMP INPUT (NO BOOST) +10 +10 +7.5 +7.5 +5 +5 +2.5 d B r +2.5 +22 +20 +20 +18 +18 +16 +16 +0 +0 +14 +14 -2.5 -2.5 +12 +12 -5 -5 +10 +10 -7.5 -7.5 +8 +8 -10 -10 -12.5 -12.5 +6 +6 -15 -15 +4 +4 -17.5 +2 +2 -17.5 d B r d B r -20 -20 +0 +0 -22.5 -22.5 -2 -2 -25 -25 -4 -4 -27.5 -27.5 -30 -30 -6 -6 -32.5 -32.
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 11 TEXTURE SWITCH — EFFECTS RETURN INPUT 2k 5k 10k 20k -10 +8.5 +8.5 d B r 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.
BOOST — ON/OFF BLOCK DIAGRAM -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 Line Out 12AX7 Input Input Stage 12AX7 Tone Stack Pull Boost Volume Tone Effects Loop Buffer 12AX7 Send Level Send Return Effects Return 6V6 Return Level Reverb Driver Spring 6V6 d B r Tremolo 12AX7
C2 101/500V Ceramic 1V DC TP2 C3 4u7/63V 473/400V R9 6K8 S1/VR2 T T NC G NC JK3 G FOOT SWITCH C10 224/400V R14 1K5 R15 1K5 VR3 100KA JK4 T T NC G NC G SEND JK5 R16 1M T T NC G NC G RETURN 80mV AC 6 3 0.7V DC TP7 C12 4u7/63V S2A Reverb C11 103/500V C15 22uF/63V R21 470R 5W 1 7 2 D V4A 12AX7 R27 VR5 220K B100K Reverb 2.
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.