3
DANGER
HIGH VOLTAGE
MAY BE PRESENT
ON FILTER CAPACITORS
DO NOT TOUCH!
SAFETY
Tube amps operate at high voltages that have the potential to injure and kill. Please remember the following
when working on this project.
Only work on tube amps when you are wide awake and sober.
Do not plug the amp in until you have gone through all of the instructions, checking and re-checking
each step.
Be aware that tubes become very hot when the amp is on and can take several minutes to cool down
after power is turned off.
Work in a ventilated area when soldering.
Always follow the one hand rule when working with an amp that is connected to power or may have
voltage present. (Any amp that has been plugged in at one time, may have high voltage present).
The one hand rule (pictured below): is a safety precaution for working on an amp that is
plugged in or could potentially have high voltages present. Using alligator clips with your
DMM, clip the ground side to the chassis and use the other side to probe at various test points
with one hand. This prevents a fatal shock which can result from current passing through the
heart. (Many people even put their other hand in their pocket or behind their back).
Always probe a tube amp for dangerous voltages present on the filter
capacitors before working on it, even if it has been turned off and
unplugged for months.
22µF 450V
Filter Cap
Positive (+) end