Z10e Electrostatic Ampli9ier User Guide
Tube Complement:
The Z10e utilizes, and is shipped with, two 12AT7 input tubes
and two 12AU7s and four EL-84 power tubes.
Tube Replacement and Tube Rolling:
The Z10e utilizes the ZOTL technology
which operates the tubes at 1/3 the heat than other tube ampli9iers and
subsequently the tube life is typically 3 times as long as other ampli9iers. Unused
tubes will typically last 10,000 hours of operation.
Note: there are very high voltages in the Z10e. When removing the cover
ensure the power cord is disconnected. Be extremely careful to ensure the
unit is off for at least 5 minutes to allow voltages to dissipate. Avoid touching
the board, as high voltages may still be present even if the unit is off
.
NOS (New old stock) tubes are available and almost always sound better than
Russian or Chinese tubes in current production. However, where these tubes have
been for the last 50 years is never certain, so sometimes they can fail or become
noisy (static or rushing sounds), and require replacement. And of course, one can
develop an af9liction known as “tube rolling”. As the ampli9ier sound will change to
re9lect the quality and “tone” of the tubes installed in it, some are often changing
between different brands to optimize the sound to their taste. In extreme cases,
adapter sockets are utilized to use exotic tubes not directly electrically compatible.
The ampli9ier has a powerful autobias circuitry, which means the ampli9ier
automatically adjusts to the optimal levels for the tubes and no adjustments are
required.
When replacing the tubes, the two labeled 12AT7 ones are the input tubes. They
must be matched so that the gain of each channel is the same (you could possibly
correct for unmatched tubes using the balance control).
Note, we often ship from the
factory with 4 7062 tubes in the 12AU7 and the 12AT7 position. If you want to change
one set to 12AU7 and 12AT7s, you must remove all four 7062s. The 7062s cannot be
intermixed with 12AU7s or 12AT7s.
The power tubes typically do not have to be matched in gain.
For the input tubes, any 12xxx equivalent tube can be used. Typically 12AT7s are
used (they have a gain of 60). There are many variants like 6201s, 5751s, 5814s, etc.
that all work well and if one set of tubes sounds better, use it.
When removing the tubes, use a gentle rocking motion as you pull out the tube. When
replacing in the socket, make sure the pins are straight and aligned correctly with the
hole pattern.
Tubes sometimes develop tube noise. With no input to the ampli9ier connected, you
should not hear any static or rushing sounds. Sometimes tubes will make a little
6
Linear Tube Audio
