ModWright Instruments LS 100 Owner's Manual page 3

Setup:
It is always recommended to remove all tubes before shipping the unit. Be sure that the LS 100 is
NOT connected to AC power and that power plug is disconnected from unit and wall outlet. Use
supplied 5/64" hex driver to remove lid screws on sides and along front and rear edges of top
panel and install (2) 6SN7 signal tubes and (1) 5AR4/GZ34 rectifier tube in ceramic octal
sockets. Signal tubes and rectifier may only be installed one way as they are spline-keyed.
Rotate tube until pins and spline align with socket and gently but firmly press the tubes down
into socket until seated.
After tubes are installed, replace lid and secure with screws. Only after this, should the power
cord be connected.
DO NOT POWER UNIT ON UNTIL LID IS ENTIRELY FASTENED. VERY HIGH
VOLTAGES ARE PRESENT INSIDE UNIT DURING OPERATION AND IT IS
CRITICAL THAT THE PREAMP ENCLOSURE NOT BE OPEN WHEN UNIT IS
POWERED ON. FAILURE TO DO SO MAY RESULT IN SERIOUS INJURY OR
DEATH.
Power Up:
When first powered on, blue LEDs above both power and mute switches will be lit. The unit
will remain in mute for approximately 45-seconds, allowing for tubes to stabilize and gently
reach operating voltage. The volume control will automatically return to the '0' position at this
time. When unit is operational, mute LED will no longer be lit.
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