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7. TUBES
7.2 GENERAL INFORMATION
Tube life
Thanks to the protection circuits and soft-start electronics, you can expect your output tubes to last for
an average of five years.
Differences in tube service life
Faulty tubes can be replaced individually. It is not necessary to replace an entire set.
Running in
New tubes can require a relatively long time (up to 300 hours) to achieve their optimum sound quality.
Faulty tubes
Manufacturing faults in tubes may only become evident after about 100 hours of use. You should there-
fore be wary of installing untested tubes. However, faulty tubes or tubes of the incorrect type will normally
not damage the amplifier. Nevertheless, they may cause loud crackling noises in your loudspeakers
7.3 REPLACING TUBES
Procedure
1
For safety reasons, only qualified personnel should open the amplifier and replace the tubes
2
Switch off the preamplifier, unplug the power cord from the wall socket and allow the
unit
10 minutes to cool down
3
The Jubilee's automatic discharge system will discharge the power supply capacitors. The red
LED [31] will be lit during this time (see Tube Layout, Section 6.1). To avoid an electric shock,
wait until this LED has extinguished before opening the case.
4
Remove the acrylic cover and the right stainless steel lid above the input selector knob [3].
Remove the black aluminum plate above the tube board.
5
Take out the old tubes
Carefully remove the tubes from their sockets, taking care not to exert sideward pressure on
the sockets
6
Fit new tubes
Please only use original OCTAVE replacement tubes. These have been tested and selected
for use in our amplifiers.
Please ensure that the tube pins are all perfectly straight before inserting your new tubes.
Straighten any bent pins very carefully by hand if necessary. No adjustments are necessary to
your amplifier after fitting new tubes.
Cleaning tips
Cleaning agents and contact cleaners are not recommended for tube sockets. Clean dirty sock-
ets with compressed air and clean dirty tube pins carefully using a wire brush. A toothbrush
dipped in isopropyl alcohol also works well.
