Linear Tube Audio ZOTL10 Mk.II, User Manual, Page: 6 / 8

Tubes
The ZOTL10 Mk.II is supplied with selected vintage tubes. The tubes
operate at low current, which allows them to have an extended
life.
Changing tubes:
EL84: The power tubes are self-biasing and do not need to be
matched for gain.
12AT7: The 12AT7s should be a matched pair.
12AU7: The 12AU7s should be a matched pair and each individual
tube should have both of its triode sections matched as well.
The sockets are tight, so gently rock the tube pins until you are
able to remove the tubes. We use high-quality ceramic tube
sockets with gold pins which are designed in such a way that the
white ceramic part may shift slightly. This is an intentional design;
the tube socket is very secure.
Before changing tubes, turn off the amplifier and wait at least 10
minutes to allow the stored power to discharge. Avoid touching
any of the components on the circuit board, especially the
vertical circuit boards.
Note on using 7062 tubes:
The 7062 is often used as a replacement for the 12AT7. This is
usually not a problem, but they do require slightly more heater
current than a standard 12AT7, which in turn requires slightly less
current than a standard 12AU7. If you want to use 7062 tubes,
you’ll need to replace both the 12AT7s and the 12AU7s with 7062s
in order to ensure that all tubes receive adequate heater current.
For more information and FAQs, please visit
www.lineartubeaudio.com or contact us at
hifi@lineartubeaudio.com.