Let the preamp tube(s) cool down, if necessary, before handling. Tube heater filaments are
somewhat more suceptable to damage when warm or hot.
Each tube should require only moderate force for removal and replacement. Gently rock
the tube back and forth a bit during removal or replacement. Avoid bending the circuit board.
Notice that the heaters of the 6922s are connected in series, and neither channel will function if
one of the filaments is open or burned out, or unless both of the 6922s are installed. Akin to those
old Xmas tree lights in the attic, no? Be careful to straighten any bent tube pins prior to
installation; pin misalignment will make fitting the replacement tube difficult or impossible, and
may damage the socket. Be careful to put replacement tubes in the proper sockets.
Never substitute other type numbers of 9-pin tubes without careful research. There are literally
thousands of types that share the 9-pin mechanical basing arrangement, but NOT the internal
electrical connections! Mechanically compatible tube plugs and sockets by no means indicate
electrical compatibility! And random experimenting can easily and quickly destroy the substitute
tube and other parts of the preamp!
Three tube types that are electrically and plug-socket compatible with the 6922 dual triode
are the 7308, 6DJ8 and the ECC88 / E88CC. There is no direct replacement for the 7044 dual
triode.
Please direct any questions to your dealer or MANLEY LABS for further assistance.
Page 11
CHASSIS
VARI
FIXED
GROUND
CIRCUIT
SERIAL #
LEFT
VARI
FIXED
LINE IN
LINE IN
OFF
ON
RIGHT
RFI SHUNT
1
2
2
1
RFI SHUNT
ON
OFF
MM IN
MC-2 IN
MC-1 IN
MC-1 IN
MC-2 IN
MM IN
