Carvin CX872 Instruction Manual - Page 4

switch is pushed in, then this knob controls the input to the right power amp. 14. SEND 1 LEVEL CONTROL-INTERNAL DSP The Send 1 control is the master input volume for the internal effects. This volume receives its signals from the EFF 1&2 control on the channels. The typical use of effects send is to adjust for maximum input to the internal effects before clipping (see DSP clip LED) 15. DSP RETURN 1 LEVEL CONTROL The RETURN 1 is the master stereo level control for the internal digital effects processor which is fed back into the L/R stereo mix. A small amount of effects is also sent to the monitor mix. 16. RETURN 2 LEVEL CONTROL The return 2 control is the stereo effects and tape return volume control. It receives its input from both the L/R tape rtn RCA jacks and the L/R 1/4" effects return jacks. This volume controls the return level being fed back into the master L/R stereo mix. A mono return into the stereo mix can be achieved by simply feeding the mono signal into both Left and right return jacks. The stereo return can also be used as another input to the stereo mix for a keyboard or other stereo gear. mono plug is plugged into these jacks, the stereo mix is disconnected from the graphic EQ and internal power amplifier allowing the new signal, that was plugged into the jack, to go through the graphic EQ and to the internal power amplifier. In the insert mode using a stereo (tip ring sleeve), the ring is the send and the tip is the return. The typical use of these jacks is for the insertion of a compressor or other outboard gear between the master preamp and the power amp. 20. TAPE JACKS The RCA jacks are Ideal for using a cassette deck. The Left/Right Tape Send RCA jacks deliver the main mix output pre the graphic EQ. If the Insert jacks are being used, the Tape Send jacks are a way to access the main mix. The Left/Right Tape Return are RCA inputs to the RETURN 2 & TAPE level control. These tape return jacks can also be used for returning another effects processor or instrument. 21. DSP EFFECTS SELECTOR Select from 16 different effects that include: Flange, Reverb, EchoReverb, & Chorus-Reverb. 25. CLIP INDICATOR The red CLIP LED indicators will start to flash when the power amp has reached its maximum output. Occasional flashing caused by lower bass frequencies is OK. However, consistent flashing caused from higher frequencies may damage high frequency drivers (exces- sive distortion). This will not damage the amp. 26. THE GRAPHIC EQUALIZER Each mixer has two nine band graphic EQ's (equalizer). The graphic EQ's are dedicated to the left and right outputs following (or post) the insert jacks of the mixer. The 9 band Graphic EQ's provide a wide degree of tonal flexibility. Adjusting: When the sliders are in their center detent position, they do not affect the audio signal. When a slider is raised or lowered from the center position, it boost and cuts respectively the level of a narrow frequency band assigned to that particular slider. It is recommended that all sliders are set in their center position before equalizing your tone. Typically low frequency feedback is in the 125 and 250 Hz range while high feedback is in the 2k and 4k Hz range. Occasionally one frequency (slider) of the equalizer will have to be pulled down to stop feedback. If many of the sliders have to be pulled down to stop feedback, the placement of the speakers with respect to the microphones may need to be reconsidered. As much as possible, try to have the main speaker facing away from and in front of the microphones not on stage behind them. The graphic EQ is mainly used to "equalize" the response of the main room and reduce feedback from microphones. Don't be afraid to use the Graphic EQ, but take care not to over-adjust. Here are some tonal reference ranges for the individual sliders to help relate the frequencies in hertz to perceived tonal changes: -the 63 Hz slider effects deep sub bass levels. -the 125 Hz is typical bass adjustments. -the 250, 500 and 1K Hz are for low mid and high mid adjustments. -the 2K and 4K Hz are for lower treble adjustments. -the 8K and 16K Hz are for the very high treble adjustments. 27. PROTECT LED INDICATOR The red PROTECT LED provides the operator with information about the status of the power amps. The PROTECT LED can come 26 on under 3 different conditions (when this happens both channels are muted by disconnecting the output speaker relays); 1) During power-up, the amplifier stays in a muted state for 11 approx. 3 sec until it determines that everything is function- 12 ing normally (no output shorts or over temp conditions). 2) When the output load draws excessive current or a direct 22 short is detected caused by a shorted speaker cable or speaker system. Reset this condition by turning the amp off 21 for two seconds and then on again. Check for shorted cables and the total speaker system impedance connected to each 15 channel (2 ohms minimum per channel). 3) Overheating is usually determined when the amp stops in the 23 middle of a performance and the PROTECT LED is on. If this 27 is the cause, leave the amp on for the fan to cool the amp down. The amp will automatically reset within 1 to 3 min- 25 utes. 24 The PROTECT LED will turn off when ready. Check for the following conditions; a) The rear intake air is restricted from outside air, b) Intake air is extremely warm, c) Excessive speaker load (try other speakers or remove speakers if you have more than one connected to each channel). Again, the minimum impedance is 2 ohms per channel. 13 18 16 17 19 14 20 22. DSP INPUT CLIP LED 17. MONITOR OUT The Monitor line out jack is the monitor mix from the monitor master level control. This is a line level output to drive an external power amplifier. The DSP CLIP LED indicates the send level to the internal effects is too high. To prevent clipping, adjust SEND 1 level control down until the clipping LED stops flashing. The individual channel EFF 1 & 2 also controls this level. 18. LEFT/RIGHT OUT The Left/Right line out jacks are post graphic EQ line output jacks for the stereo mix. The same signals are also being fed to the internal power amplifier. Note: If the insert jacks are being used for patching or if the power amp switch is being used, then that new signal will also be present on the corresponding Left/Right Line Out jack. The stereo mix may still be accessed at the RCA Tape Send jacks if needed. 19. INSERT JACKS The Left/Right INSERT jacks are pre-graphic EQ, pre-power amp, and normalized to the stereo mix L/R MAIN level control. When a 23. POWER LED The Power LED indicates when the mixer is powered up. 24. PHANTOM POWER SWITCH AND LED The Phantom power switch turns on the microphone phantom power in the channel XLR jacks. This power is used for supplying a bias voltage to condenser microphones. The LED indicates the phantom power is turned on. The phantom power will not damage dynamic microphones. HELPFUL HINTS 1) FEEDBACK: To reduce feedback, the placement of the speakers with respect to the microphones may need to be reconsidered. As much as possible, try to have the main speaker facing away from and in front of the microphones not on stage behind them. The graphic EQ may be used to reduce feedback from microphones. See 26. THE GRAPHIC EQUALIZER 2) SOUND HEARD ONLY ON LEFT SIDE: Check power amp selection switch. Switch out for stereo mode, switch in for main/monitor mode. 3) No High Frequencies: Check the channel tone controls and EQ settings. The tweeters or midrange drivers may have been damaged or blown from feedback or overpowering. 4) Main House AC breaker trips : at high output levels, high powered amps require separate circuit breakers (120V:20A, 230V:10A) for delivering their full power. Most 120V homes have only 15 amp breakers you may simply be running too much power 5) The Amp's rear circuit breaker trips: Full power at 2Ω (4Ω bridged) can cause the amps circuit breaker to trip. This is normal with high powered amps because they can deliver more than their full rated output if the clip LED flashes.