3rd Power Kitchen Sink 6VEL User Manual page 17

Proper Power & Rectifier Tube Use:
CAUTION (once again):
NEVER touch hot tubes!!! Temperatures can exceed 500˚F and cause severe burns!
Your amplifier ships with the bias settings optimized for maximum flexibility and safety. During QC
and final testing, the bias is set maximum safe power dissipation (approximately 60% of a given
tube's performance rating). Factory bias setting will be noted on the back panel of all units.
Base 40 amplifiers are equipped at the factory with JJ E34L power tubes and a JJ GZ34 rectifier tube.
You may swap out the GZ34 with a 5U4GB rectifier tube WITHOUT re-biasing your amp. You can
safely operate in SS or Tube Rectifier Mode as selected via the Standby Switch.
Base 20 amplifiers are equipped at the factory with JJ 6V6GC power tubes and a JJ 5U4 rectifier
tube. You may swap out the 5U4GB with a GZ34 rectifier tube WITHOUT re-biasing your amp. You
can safely operate in SS or Tube Rectifier Mode as selected via the Standby Switch.
Pro and Deluxe amplifiers are equipped at the factory with JJ E34L power tubes and a JJ GZ34
rectifier tube unless an alternate tube complement has been specified by the customer or dealer.
They also ship with a full set of the alternate power and rectifier tubes. If loaded with E34L/GZ34
set, a boxed set of 6V6GT/5U4GB are included.
Should you wish to swap to the other set of tubes, you must do so in like-kind pairs as mixed tubes
will not operate correctly and may be hazardous to your amplifier. You can safely substitute either
rectifier tube. Again, use caution to mount the correct tubes in the appropriate tube sockets.
OPERATION NOTES:
Please refer to the chassis/tube layout on page 19 when attempting to swap any tube.
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