User manual FENDER LX-1506

[. . . ] Carefully advance the master control on your signal source until the sound level from the speaker is just past the "correct" level; i. e. Remove the input signal from the source, leaving the master control ( and any input controls on the source) set as they were. If the system is noisy (hissy), reduce the setting of the INPUT LEVEL control(s) slightly and repeat this step. You must "juggle" the settings of the source's controls until you find a combination that gives you the desired amplifier output, freedom from clipping caused by excessive output demands placed on signal source, and poor signal-tonoise performance caused by excessive amplifier gain. [. . . ] The threshold for the peak indicator automatically adjusts for load impedance and supply voltage variations. 2. REAR PANEL E & F - OUTPUT CONNECTORS Each channel is provided with a single 1/4" phone jack (E) and a pair of five-way binding posts (F) which will accommodate a single pair of dual banana plugs (multiple stacked banana plugs are not recommended as they tend to fall out), spade lugs or bare wire. If the speaker wire is terminated with spade lugs, make sure that the lugs are tin or gold plated brass or copper, not plated steel. Non-linear contact resistance phenomena will degrade the sonic integrity of any amplifier at the speaker/amplifier interface. The Channel A and Channel B outputs are spaced on 0. 75 inch (19 mm) centers so that one "double banana plug" can be used for bridged operation. During performance verification measurements, use the five-way binding posts only. B - LIMIT SWITCHES The Limit Switch is used to defeat the internal compressor circuits. C - INPUT LEVEL CONTROLS Two continuously variable attenuators control the amplifier's input sensitivity. Control settings can vary between zero attenuation (maximum clockwise rotation) and infinite attenuation (maximum counterclockwise rotation). At the full clockwise rotation, a +1. 8 dBV input signal is required for rated output. Each gain control is independent except for the Mono Bridge mode where Channel A is the active control and the Channel B control is inactive. Refer to the Amplifier Operation section for additional information on proper adjustment of the input level controls. CAUTION: Do not operate the amplifier in the two channel (stereo) mode with a load impedance of less than 4 connected to either channel. Do not operate the amplifier in the Bridged Mode with a load impedance of less than 8 . D - POWER LED INDICATOR AND SWITCH The power switch turns the unit on and off. This approach eliminates most of the signal loss due to speaker cable resistance so the speakers are fed all of the amplifier's power without the need for heavy cables. This can actually save money in many instances. Always use stranded wire for three reasons: 1) It is more flexible and less prone to metal fatigue breakage. 2) If an end is nicked while insulation is being stripped for connection, only one or two strands will break and not the entire wire. 3) There is some evidence, though disputed, that higher frequency audio signals flow along the outside of each conductor (skin effect): if this is so, the more strands, the lower the effective cable resistance to high frequencies. In cases where speakers and power amplifiers are located far away from the signal source (a mixer or a preamp), balanced line" signal cables are a wise choice. SPEAKER WIRE GAGING TABLES SPEAKER WIRE GAUGE SPEAKER WIRE LENGTH (30. 5 m-UP) (15. 25-30. 5 m) (7. 60-15. 25 m) 100'-UP CROSS REFERENCE TABLE 10 12 12 14 14 16 18 18 18 AWG 18 16 14 12 10 CROSS SECTION [mm2] 50'-100' 0. 83 1. 32 2. 10 3. 32 5. 27 *25'-50' 14 *16 16 18 18 18 (3. 05-7. 60 m) (0. 00-3. 05 m) 10'-25' 0'-10' 4 *8 16 SPEAKER IMPEDANCE [z] *Example - The length of the speaker wire required is between 25-50 feet (7. 60-15. 25 meters) and the speaker impedance is 8 ohms. The minimum recommended speaker wire gauge is 16. 5 CAUTION: NEVER use coiled cords for speaker hookup, even in an emergency. Coiled guitar-type cords usually have higher internal resistance than the speakers themselves. This is due to the light-gauge wire used to keep the coil cords flexible. These cords will prevent most of the power from reaching the speakers. In high power operation, a coil cord can melt causing a fire hazard and possible damage to the amplifier. As a general rule, both straight and coiled guitar-type connecting cords make poor speaker cables. [. . . ] If you have mounted all your sound equipment in a rack or portable case, you can ensure that everything stays calibrated by marking the settings of the necessary controls. Small pointers made from masking tape are visible in dim light and can be removed with alcohol or rubber cement thinner without damage to the paint on most front panels including those of the Fender amplifiers. Be sure to check the finish in an inconspicuous place to determine the suitability of any cleanser. Assuming you are NOT turning all the equipment on at once with a switched power receptacle "strip", be sure to turn on the power amplifier last. [. . . ]