© 1995-2007 CORNELL Musical Equipment Design & Development
7
Valve Replacement
Valve life varies depending upon playing style and application. Power valves have a
much shorter life than pre-amp valves, which can last for years.
To maintain the optimum performance of your amplifier, the valves should only be
replaced with the same valve types, as specified in the illustration below.
When changing valves, ALWAYS unplug the amplifier, and remember that the
VALVES ARE HOT ! Wait for the valves to cool, or replace valves when the amplifier
has not been used for several hours.
Your
Plexi 45/50
amplifier has 6 valves: three pre-amp valves (12AX7/ECC83), two
power valves (EL34), and a rectifier valve (GZ34).
Valve Line-up
Mains
Transformer
Output
Transformer
EL34
EL34
ECC83
ECC83
Front panel
GZ 34
ECC83
