Feedback humming noise

Sometimes empty/unplugged channels introduce noise to the amplifier. You can always try to connect all of the input channels to some external mobile phone/mp3 player, etc. and then set these equipments to the minimum possible volume (mute if possible). This should remove the "atmospheric" audio noise.

Feedback occurs whenever a microphone is being amplified, and it picks up its own signal above a certain level. Unfortunately, there's no way to reduce this possibility using just the Numark C3FX - you can only turn the microphone level down. The only way to reduce feedback through a speaker system is to use a graphic equalizer. Here's a good resource for how to do that: http://rfmedia.hubpages.com/hub/Controlling-Microphone-Feedback-with-a-Graphic-Equalizer

You have two clues here to help you solve this problem. First since the volume control turns up the noise, whatever causes this noise is before the volume control. You don't state that the noise is in one channel. If is in both, then a part found in either of the channels can not be the cause. If it is common to both channels you are looking at something common to both channels that is causing it. For example something in the power supply?

You seem to have some feedback hum from somewhere. I would think it might be caused by a faulty connection somewhere.

Determine where in the mixer's signal path to connect the unit. Your options are:
1. One or two individual microphone channels via the mixer's CHANNEL INSERT in/out jacks.
2. The monitor mix output via the mixer's MONITOR OUT jacks.
3. The main mix output via the mixer's MAIN OUT jacks.

2 Connect a balanced cable with the appropriate connectors from CHANNEL INSERT OUT jacks on the desired mixer channel to INPUT RIGHT or LEFT on the Feedback Destroyer's back panel for individual microphone channels. Connect a balanced cable with the appropriate connectors from the OUTPUT RIGHT or LEFT jacks on the Feedback Destroyer's back panel to that mixer channel's CHANNEL INSERT IN jack.

3 Connect a balanced cable with the appropriate connectors from the mixer's MONITOR OUT jacks to the INPUT RIGHT or LEFT jacks on the Feedback Destroyer's back panel for the monitor signal path. Connect a balanced cable with the appropriate connectors from the OUTPUT RIGHT or LEFT jacks on the Feedback Destroyer's back panel to the monitor amplifier INPUT jack or amplified monitor speaker INPUT jacks.

4 Connect a balanced cable with the appropriate connectors from the mixer's MAIN OUT jacks to the INPUT RIGHT or LEFT jacks on the Feedback Destroyer's back panel for the main mix (FOH) signal path. Connect a balanced cable with the appropriate connectors from the OUTPUT RIGHT or LEFT jacks on the Feedback Destroyer's back panel to the main amplifier INPUT jack or amplified house speaker INPUT jacks.

Normally you find where feedback occurs, notch it out with the EQ and recheck for feedback. When system is stable you can take out the ferret.

Check List :
CD Deck 1 to Channel 1 CD Input
CD Deck 2 to Channel 2 CD Input
Mixer booth output to AMP's AUX or CD input.
use the BOOTH rather than the MASTER
even if you think you've done all these checks, check them again.
trust me I've been a DJ for 15 years & wired up **** loads of systems & still manage to ******* the wiring now & again lol.
you mite need to run an earth from your mixer to your amp.
One more thing, just out of interest you don't happen to have an amp with surround sound do you?
because if you do then switch the effects completely off this should sort it.

e-mail [email protected]

it could be your guitar pickups. try using another guitar or getting your pickups waxed at your local music store. also if your playing in a small room kind of loud, or if your using single coil pickups (like fender statocaster pickups) you will definitely get a feedback noise. if that does not work let me know.

Your mixer is already grounded, and does not need any additional grounding. It is grounded through the Power Cord.

Now, the feedback might be coming from one of the units you have connected to the mixer. The issue could also be the cable you are connecting to your recorder. Are you recording to a computer, or to some other external recorder (CDR / DVR / MDR, etc?) - try a different cable. Also try the different outputs on the mixer - you have 2 balanced line outputs you can record directly from. Don't use the RECORD OUT line, it's an unbalanced line, and if you want a good quality signal to record, your best bet is to use the XLR outputs. However, that might be connected to your amp or something.

What do you have going to the unit? Disconnect everything, and try by connecting each item 1 by 1, to eliminate where this feedback is coming from. Also, check for any ground loops that you might have, if you have a lot of equipment hooked up in your set up. (Educate yourself on Ground Loops)

If all else fails, get yourself a HUM ELIMINATOR.

- OPTiC
DJ Equipment Repair & Service
A DJ Pro Audio Co.

your mixer should be grounded by the power cord, and the decks have a seperate ground wire which connects, usually on a screw terminal, to the mixer, which provides the ground for the decks. I would try the headshells to make sure they are tight and connected correctly also make sure the power socket on the wall is earthed properly.