Tubes Position; Internal View - Jadis JPL Owner's Manual

Tubes position

Warning: Do not open your preamplifier when the unit is working or
when the mains power cord connects the preamplifier to the electrical
network. Switch off the unit and disconnect all the cables before opening.
Open your preamplifier only if you have to change the tubes and, after
having contacted your dealer or distributor.

Internal view

front
Attention: For mounting the tubes, do not force them, this may
damage the sockets. Warning: respect the type of tube which is used.