User manual QSC AUDIO MODEL 3800

[. . . ] 1. 4 Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . EXPLANATION OF GRAPHICAL SYMBOLS The lightning flash with arrowhead symbol, within an equilateral triangle, is intended to alert the user to the presence of uninsulated "dangerous voltage" within the product's enclosure that may be of sufficient magnitude to constitute a risk of electric shock to humans. 3 3 3 4 The exclamation point within an equilateral triangle is intended to alert the users to the presence of important operating and maintenance (servicing) instructions in the literature accompanying the product. II: BASIC INSTRUCTIONS 2. 1 Unpacking and Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 2 Important Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. 3 Quick Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 III: OPERATION 3. 1 Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] 1/4-inch connectors are suitable for low-cost portable systems, but must be removed and replaced frequently to avoid corrosion build-up. 1/4-inch plugs are not recommended for long, undisturbed service, especially in corrosive environments. The "military" brass-type plugs are especially bad in this respect, because they don't match the plating of the input jacks. XLR plugs are preferred by professional users for reliable contact and better retention. For permanent wiring harnesses, the barrier strip is the cheapest and best. The signal wiring can be stripped and wrapped around the terminal screws, or spade terminals can be soldered or crimped onto the ends of the signal conductors. When crimping, be sure to use the proper tool with generous pressure, and test the resultant crimp by pulling while closely inspecting. If the wire wiggles inside the crimped terminal, the contact will go bad. The spade lug, or bare wire ends, can then be tightly screwed down to the proper positions on the barrier strip. If high pressure is maintained in the crimp and the screw terminal, a "gas-tight" connection is formed which will exclude corrosion for many years. 3. 4 OCTAL MODULE ACCESSORIES 3. 41 3. 42 Octal Socket Each channel has an octal socket for active and passive plug-in accessories. This is shipped with a protective label to prevent corrosion of the pins. This is a way to fully use both channels when only a single speaker is driven. To engage the bridged-mono mode of the Model 1100, a slide switch must be set through a hole in the bottom of the amplifier. Due to the danger of touching live terminals inside the amplifier, BE SURE TO REMOVE ALL POWER AND DISCONNECT THE AC PLUG before resetting the switch. In accordance with the label on the bottom, set the switch towards the front for bridged-mono use, and towards the rear for normal stereo use. To engage the bridged mono mode on the Model 1200, 1400, or 1700, there is a separate slide switch located below the barrier strip inputs on the rear panel. Follow the directions on the label to engage the switch in the "Bridge" position. 12 Connect the amplifier input to Ch. 1 Gain control, which now controls the entire amplifier. Do not feed another input into Channel 2. 2 Gain control should be kept off for safety. An 8 or 16 ohm speaker load should be connected across the two red speaker terminals, using the red terminal of Ch. 1 as the "+" or "hot" terminal, the red terminal of Ch. [. . . ] The fuse values shown are calculated for fast-blow fuses, which will carry 135% of their rating for an hour, and which blow within 1 second at 200% current. The RMS power rating shown is correlated to 135% of the fuse current. The fuse voltage is not critical; 32 volt fuses should have the lowest resistance which will avoid loss of damping factor. RMS Power 30w 50w 75w 100w 200w 400w 4-ohm Load 2. 0 2. 5 3. 0 4. 0 5. 0 7. 5 8-ohm Load 1. 5 1. 6 or 2. 0 2. 0 or 2. 5 2. 5 3. 0 or 4. 0 5. 0 16-ohm Load 1. 0 1. 25 1. 5 1. 6 or 2. 0 2. 5 3. 0 or 4. 0 Table 4. 5 Fuse Ratings (values in amps) The power may also be limited with active circuitry. [. . . ]