cider Posted December 10, 2008 Share Posted December 10, 2008 could someone please tell me if speaker hum can be caused by faulty leads before I buy a new set !!! Link to comment Share on other sites More sharing options...
MarkPAman Posted December 10, 2008 Share Posted December 10, 2008 Yes it can. But it can be caused by many other things too. Tell us a litle more & we'll try to narrow it dow a bit. :D Link to comment Share on other sites More sharing options...
cider Posted December 10, 2008 Author Share Posted December 10, 2008 thanks 3rd time lucky! I have a 1300 w power amp which at the moment constantly gives a very noticable hum from the speakers even with no sources pluged into the mixer.The only time it stops is when one of the input plugs is removed from the back of the amp. or to put it another way as soon as that lead is pluged into the amp the speakers pop and hum even if the other end of the lead is not connected. Link to comment Share on other sites More sharing options...
fogg Posted December 10, 2008 Share Posted December 10, 2008 How long are these leads? Are they balanced? Link to comment Share on other sites More sharing options...
MarkPAman Posted December 10, 2008 Share Posted December 10, 2008 Can you swap leads around to eliminate a faulty one? If you have L+R you could just swap them. If the mixer's a long way from the amp, (in fact how long is the cable) could you move it closer to try this test. Do you hear hum your mixer on headphones? Are the mixer's output, the cable, & the amps input all balanced (as in 3 pin XLR or TRS jack)? Link to comment Share on other sites More sharing options...
Warthog Posted December 10, 2008 Share Posted December 10, 2008 could someone please tell me if speaker hum can be caused by faulty leads before I buy a new set !!! Sometimes an earth problem. Link to comment Share on other sites More sharing options...
cider Posted December 10, 2008 Author Share Posted December 10, 2008 1 mtr long and not sure what you mean by ballanced :D A concurrent post has been automatically merged from this point on. one end is phono I think and other 3 pin.the cable is single core with a screen used as conductor Link to comment Share on other sites More sharing options...
fogg Posted December 10, 2008 Share Posted December 10, 2008 If they are jack leads. Balanced basically means that it will look like a stereo jack (2 rings on the sleeve of the jack). If its a XLR - XLR using 2 core plus screen cable then it'll be balanced. Ok fron the concurrent post above it sounds like the cables are unbalanced. I take it that the mixer is a dj mixer with the output on phonos? You could try running the phonos into a couple of passive di's then XLRs to the amp. But it could be that the wiring from the phono to the XLR is to blame. Center of the phono should go to pin 2 and the outer to pin 3. Try it with pin 3 connected to pin 1 and also without see if that makes any difference. Link to comment Share on other sites More sharing options...
tolley1466 Posted December 11, 2008 Share Posted December 11, 2008 If you want to narrow your search down to what lead, mic, etc that is causing the hum, turn your faders up so you can hear the hum and drop out or mute each channel until the hum has gone, then investigate into the cable or device that is causing the hum. Oops, sorry just read about the power amp, time for bed I think! Link to comment Share on other sites More sharing options...
johndenim Posted December 11, 2008 Share Posted December 11, 2008 Hopefully time for Bobbsy or Rob to intervene?Maybe a beginners guide? No offence OP, welcome to the blue room. Link to comment Share on other sites More sharing options...
upsuEnts Posted December 11, 2008 Share Posted December 11, 2008 1 mtr long and not sure what you mean by ballanced :P A concurrent post has been automatically merged from this point on. one end is phono I think and other 3 pin.the cable is single core with a screen used as conductor Are pins 1 and 3 linked on the XLR? (the 3 pin one)This link might be of some use:http://www.dplay.com/dv/balance/balance.html Link to comment Share on other sites More sharing options...
berry120 Posted December 11, 2008 Share Posted December 11, 2008 thanks 3rd time lucky! I have a 1300 w power amp which at the moment constantly gives a very noticable hum from the speakers even with no sources pluged into the mixer.The only time it stops is when one of the input plugs is removed from the back of the amp.or to put it another way as soon as that lead is pluged into the amp the speakers pop and hum even if the other end of the lead is not connected.I'm slightly confused as to what you mean here - does the hum start when just the cables are connected to the amp (i.e. the mixer isn't plugged in at all) or only when the mixer's connected to the other end? And is it the same input plug that, when removed, causes the hum to stop or is it either one? If you wiggle the cable around after it's been plugged in, do you get more pop / crackle than when you just leave it alone? If so, then I would've thought the cable's definitely at fault. Link to comment Share on other sites More sharing options...
Rob_Beech Posted December 11, 2008 Share Posted December 11, 2008 Morning. If the problem occurs when the desk is plugged in to the other side of the cables, unplug the leads at the desk end. If the hum goes away the issue is with the desk, or something plugged into it (though u said it occurs with no sources plugged in). If the hum remains the issue is with the cables. Check the wiring is correct. The tip of the phono should go to pin 2 of the XLR and the screen to pin 1. Pin 1 and 3 should be joined. This is of course unless the amp is pin 3 hot of course, in which case the role of 2 nd 3 should be reversed. DO you get an audio signal aswell when you plug something in and play music? Link to comment Share on other sites More sharing options...
cider Posted December 11, 2008 Author Share Posted December 11, 2008 yes I can hear music fine but constant hum.gonna get some jack to jack leads are these better then XLR to phono ? Link to comment Share on other sites More sharing options...
fogg Posted December 12, 2008 Share Posted December 12, 2008 Does your mixer also have jack outs? If so something like this CLICKY which is a ballanced jack - XLR cable would do the job. But this does depend on if the jack outs on your mixer are ballanced. Link to comment Share on other sites More sharing options...
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