VHT Special 12/20 RT Head - Manual (Page 5)

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12AX7 12AX7 12AX7 12AX7
6V6 6V6 6V6
Internal Speaker
16 ohms
6L6, EL34
HIGH VOLT
6V6, EL84
LOW VOLT
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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.
2. DC Out: Plug the included 9-volt DC power supply cable into this jack to power your pedal(s) or pedal board. The LED
will illuminate at all times when powered. If the LED is not illuminated, check the internal DC Out fuse.
3. Effects Loop Send and Return Jacks: The post-preamp Effects Loop can accommodate a wide range of effects. The
send level is dependent on the preamp gain. High preamp gain levels may overdrive some sensitive guitar-level effects ped-
als. The Return jack has a pedal-friendly 1 megohm input impedance.
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 low-impedance (unbalanced) signal to other equipment such as mixing consoles or other amplifiers. Multiple
VHT Special 12/20RT, Special 12/20 or Special 6 Ultra amplifiers can be linked by connecting the Line Out jack to the Effects
Return of the second 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-position slide switch selects the appropriate output impedance to match your speaker cabi-
net’s impedance.
6. Speaker Output Jacks: These two jacks are wired in parallel. The Special 12/20RT combo has a 16-ohm speaker that
is connected to the internal speaker jack. The combo’s speaker remains connected when using the external Speaker Output
jacks. When using the combo with an additional 16 ohm speaker cabinet, switch the Impedance selector to 8 ohms.
7. Power IEC Receptacle/Line Voltage Selector: Use the included power cord with this unit in accordance with the AC
line voltage and frequency ratings listed on this manual and rear panel of this amplifier. Your amplifier will ship with the cor-
rect voltage for your region; when traveling to different countries, remove the clear plastic protector and flip the switch to
the appropriate voltage. For lowest noise and safest operation, always provide the amplifier with proper AC grounding.
8. 12/20-Watt High/Low Power Voltage Selector: Located behind the rear panel, this switch selects the appropriate
maximum voltage for each output tube type. Set it to the 20-watt High-Volt position when using 6L6 or EL34 output tubes.
Set it to the 12-watt Low Volt position when using 6V6 or EL84 output tubes. (EL84 output tubes require 6V6-to-EL84 tube
socket adapters.)
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