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Manley – Manley MOVING COIL & MOVING MAGNET PHONOGRAPH PREAMPILFIER User Manual

Page 9

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Let the preamp tube(s) cool down, if necessary, before handling. Tube heater filaments are
somewhat more susceptible 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 tubes of each channel are connected in series, and either channel will function if one
of the filaments is open or burned out, or unless all of the tubes 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.

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 your preamp!

Three tube types that are electrically and plug-socket compatible with the 6922 dual triode are the
7308, 6DJ8 and the ECC88 / E88CC.

Please refer to Fig. 2 for tube location.

Please direct any questions to your dealer or MANLEY LABS for further assistance:
[email protected]

Chinook Owners Manual 7

MANLEY

LABORATORIES, INC.