14. AC LINE IN: Firmly insert the supplied AC power cord into this socket until it is fully seated. Plug the male end of the cord into a grounded AC outlet. DO NOT DEFEAT THE GROUND PRONG OF THE AC PLUG! 15. FUSE: This protects the unit from damage due to overload conditions or power line surges. If the fuse blows, replace it only with the same size and type. 16. POLARITY: Place this switch in the position that provides the least electrical buzz from the unit. 17. BIAS SECTION: These two controls and sets of LEDs allow the user to properly bias the power amp. See �Setting Tube Bias� on page 7 for a complete description of how to use this section. 18. SLAVE OUT: This jack receives the same signal that is being sent to the power amp. It is useful for powering another amp (slave) from this unit�s preamp.
19. BALANCED OUT: This XLR jack is the preamp output. Thus, it will include any processing done in the Preamp Out/Power Amp loop (20, 21). This signal can be used to feed an external power amplifier, mixing console or house PA system. 20. PREAMP OUT: This jack carries the post-Master (10) signal. Using this jack does not break the path to the power amp. This signal can be used to feed an external power amplifier, mixing console or house PA system. 21. POWER AMP IN: This jack accepts a signal to be sent to the power amp and the Slave Out jack (18). Using this jack breaks the path from the signal that was present at the Preamp Out jack (20). This can be used as a post-Master (10) patch point.
22. IMPEDANCE SELECTOR: Use this switch to match the output impedance of the amp to the speaker(s) being used (2 or 4 ohms). For help in deciding the total impedance of your system, consult the chart below.
Cabinet Impedance 2 ohms 4 4 8 8 ohms ohms ohms ohms Number of Cabinets 1 1 2 2 4 Total Impedance 2 ohms 4 2 4 2 ohms ohms ohms ohms
23. SPEAKER OUT: Two 1/4� phone jacks and one Speakon® jack are provided for connecting speakers to the unit. These jacks are wired in parallel. When operating at or near full power, the Speakon® jack is recommended for use over the 1/4� jacks due to its higher current handling capability.
NOTE: In some areas 1/4� speaker jacks are not acceptable for use on amplifiers with high output power levels. For this reason the 1/4� jacks on your amplifier may not be accessable � use the Speakon® jack.
