Operating Instructions
Using the Rock Block as a guitar amplifier
Connect the guitar or effects pedal to the INPUT jack using a guitar cable with a ¼” mono
plug. Also connect a speaker cabinet to the SPEAKER jack using a speaker cable with a
¼” mono plug. The ideal speaker impedance is 8 ohms, but 4 and 16 ohm speakers can
be used while still providing excellent sound. See the “Vacuum Tube Selection” section
for matching the output vacuum tube to the speaker impedance. If a speaker cable is
connected to the SPEAKER jack, then a 4-16 ohm speaker should be connected to the
speaker cable to avoid possible damage to the amplifier.
Connect the supplied external power supply to the 12 DC jack and plug the AC 3-pronged
plug into a wall socket. Turn on the amplifier with the POWER switch. If the green LED
is not ON, then push the footswitch to un-bypass the amplifier. The green LED should be
ON.
For a clean guitar sound: Turn the VOL knob maximum clockwise. Set the BOOST
switch to the left (minimum) position. Adjust the GAIN knob for maximum volume without
distortion. Adjust the BASS switch and TONE knobs to taste.
For a “bluesy” or “crunchy” guitar sound: Turn the VOL knob maximum clockwise. Set
the BOOST switch to either the left or center position. Adjust the GAIN knob for the
desired amount of distortion.
For a “hi-gain” or “lead” guitar sound: Turn the VOL knob maximum clockwise. Set the
BOOST switch to either the center or right position. Adjust the GAIN knob for the desired
amount of distortion, sustain and feedback.
For reduced volume with high gain: Turn VOL knob counter-clockwise. This will reduce
the overall volume of the amplifier. The distortion will transition from output tube to
preamp tube distortion as the volume is reduced.
Using the Rock Block as a distortion/boost pedal
Connect the guitar or effects pedal to the INPUT jack using a guitar cable with a ¼” mono
plug. Also connect the OUTPUT TO AMP jack to another amplifier or effects pedal using
an instrument cable with a ¼” mono plug. Do not plug anything into the SPEAKER jack.
The output volume of the Rock Block, when used as a distortion/boost pedal, is controlled
with the OUT VOL knob. The BYPASS footswitch is used to bypass the Rock Block. All
other controls are used in the same way as when the Rock Block is used as an amplifier
to drive a speaker.
If the Rock Block is driving an amplifier that is grounded (has a 3-prong power cord), then
it is best to use the included AC adapter (3-prong to 2-prong) with the Rock Block to
reduce hum, especially when the Rock Block is bypassed. Plug the Rock Block power
cord into the adapter, and then plug the adapter into the wall socket. If the amplifier the
Rock Block is driving is not grounded or if the Rock Block is driving a speaker, then do
not use the AC adapter so that the Rock Block is grounded and hum is reduced.
