lowdowner Posted September 25, 2012 Share Posted September 25, 2012 It's very minor, but when I 'damp' my strings with the palm of my hand the 'hum' I can hear through the amp stops. This makes the hum when i'm *not* damping the strings seem very loud. It happens with either of my amps so it's definitely something to do with the guitar (i've tried two cables)... It happens wherever I play i.e. it's not my earthing in my home. Is this normal? Should I just ignore it and play on? Quote Link to comment Share on other sites More sharing options...
rogerstodge Posted September 25, 2012 Share Posted September 25, 2012 What bass are you using? Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 25, 2012 Author Share Posted September 25, 2012 warwick thumb 4 string bolt on (2011 model) Quote Link to comment Share on other sites More sharing options...
KingBollock Posted September 25, 2012 Share Posted September 25, 2012 This might sound strange, but I'm curious... Does this happen no matter what orientation you are in to your amp? As in, if it happens when you are facing your amp, or the amp is right behind you, does it stop, or get quieter, when you turn so you are at a right angle to your amp? Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 25, 2012 Author Share Posted September 25, 2012 [quote name='KingBollock' timestamp='1348601133' post='1815883'] This might sound strange, but I'm curious... Does this happen no matter what orientation you are in to your amp? As in, if it happens when you are facing your amp, or the amp is right behind you, does it stop, or get quieter, when you turn so you are at a right angle to your amp? [/quote] Ah, now, that's interesting. Are you thinking some kind of electro-magnetic feedback of some kind? The answer is - I don't know! I will check it out in the morning and report back... funnily enough, I didn't think to experiment with that.... Quote Link to comment Share on other sites More sharing options...
rogerstodge Posted September 25, 2012 Share Posted September 25, 2012 Does it go if you roll the tone off? I had an old aria pro II and the earth wire had broken which was the cause, but doubt its that on a 2011 warwick? Quote Link to comment Share on other sites More sharing options...
KingBollock Posted September 25, 2012 Share Posted September 25, 2012 [quote name='lowdowner' timestamp='1348601274' post='1815888'] Ah, now, that's interesting. Are you thinking some kind of electro-magnetic feedback of some kind? The answer is - I don't know! I will check it out in the morning and report back... funnily enough, I didn't think to experiment with that.... [/quote] I'll be honest, I have no idea... It happens to me but all my amps and Basses are squashed together with 2 running PCs and their monitors, and a bunch of different kinds of lighting, including strip lights. I'd be surprised if there wasn't some kind of buzz in here. Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 25, 2012 Author Share Posted September 25, 2012 [quote name='rogerstodge' timestamp='1348601488' post='1815896'] Does it go if you roll the tone off? I had an old aria pro II and the earth wire had broken which was the cause, but doubt its that on a 2011 warwick? [/quote] No - it's constant Quote Link to comment Share on other sites More sharing options...
Dr M Posted September 27, 2012 Share Posted September 27, 2012 I believe this is related to the way electric guitars and basses are earthed - essentially, you [i]are[/i] the earth. If you look at wiring diagrams, you'll see an earth wire going from p-ups to pots, usually to the bridge. This means that the earth is only actually having an effect (ie. cutting out that 50Hz hum) when you're touching the strings. Quote Link to comment Share on other sites More sharing options...
ped Posted September 27, 2012 Share Posted September 27, 2012 [quote name='Dr M' timestamp='1348757909' post='1817813'] I believe this is related to the way electric guitars and basses are earthed - essentially, you [i]are[/i] the earth. If you look at wiring diagrams, you'll see an earth wire going from p-ups to pots, usually to the bridge. This means that the earth is only actually having an effect (ie. cutting out that 50Hz hum) when you're touching the strings. [/quote] With this in mind, I have in the past taken a slice of tin foil to a pickup screw so that when I anchor my thumb I earth the bass so it doesn't buzz when I release the strings. I did this with a couple of jazz basses and it worked a treat. With the Warwick though it'll be difficult as there's no scratchplate to cover the foil... How about a cool ring with a wire attaching you to the bridge Quote Link to comment Share on other sites More sharing options...
lettsguitars Posted September 27, 2012 Share Posted September 27, 2012 It's the earth buzz. Your strings are grounded and you are indeed the earth when you play. A lot of instruments will have an audible buzz when they are not earthed. It should be hardly noticable unless you plug into any equipment, amp,mixer etc that has a bad earth somewhere. Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 27, 2012 Author Share Posted September 27, 2012 [quote name='lettsguitars' timestamp='1348759166' post='1817830'] It's the earth buzz. Your strings are grounded and you are indeed the earth when you play. A lot of instruments will have an audible buzz when they are not earthed. It should be hardly noticable unless you plug into any equipment, amp,mixer etc that has a bad earth somewhere. [/quote] You're right about it being quiet - but like a lot of these things once you hear it you begin to notice it more and more. In some of our songs there are some silent breaks and I now rest my palm on the strings to silence them completely. If I don't I immediately hear the buzz! Just wanted to check it wasn't a wiring issue which it sounds like it's not Quote Link to comment Share on other sites More sharing options...
ped Posted September 27, 2012 Share Posted September 27, 2012 An active bass will stop the problem Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 27, 2012 Author Share Posted September 27, 2012 my bass *is* active! Quote Link to comment Share on other sites More sharing options...
ped Posted September 27, 2012 Share Posted September 27, 2012 [quote name='lowdowner' timestamp='1348763422' post='1817898'] my bass *is* active! [/quote] Ah!! Well that's strange. Or I'm strange. Or I don't know what I'm talking about! Quote Link to comment Share on other sites More sharing options...
uncle psychosis Posted September 27, 2012 Share Posted September 27, 2012 A lot of people get this the wrong way round. The noise stops when you touch the strings because the bass is grounding you, not because you are grounding the bass. The human body is like a big antenna, so by being in close proximity to the electronics of your bass you induce a lot of noise. When you touch the strings you ground yourself and the noise disappears. Humans aren't normally grounded- that's why you occasionally get static shocks and have to wear those ESD bracelets when working on delicate electronics. You can reduce the noise by shielding the pickups and control cavity. Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 27, 2012 Author Share Posted September 27, 2012 [quote name='uncle psychosis' timestamp='1348764911' post='1817922'] A lot of people get this the wrong way round. The noise stops when you touch the strings because the bass is grounding you, not because you are grounding the bass. The human body is like a big antenna, so by being in close proximity to the electronics of your bass you induce a lot of noise. When you touch the strings you ground yourself and the noise disappears. Humans aren't normally grounded- that's why you occasionally get static shocks and have to wear those ESD bracelets when working on delicate electronics. You can reduce the noise by shielding the pickups and control cavity. [/quote] Oh, so if I ground myself (maybe a cable to a copper pin sunk in the ground) the hum would stop? I'm not going to go to the faff mind, but I'm really pleased to know what's actually going on. Mind you, I *could* be tempted to experiment with a tin foil pointy hat thing - I've seen them on films so they probably work? Quote Link to comment Share on other sites More sharing options...
Fat Rich Posted September 27, 2012 Share Posted September 27, 2012 [quote name='ped' timestamp='1348759946' post='1817840'] An active bass will stop the problem [/quote] Some active pickups like the older style EMGs don't need an earth, they're not connected to the bridge by a wire. So no earthing hum, less risk of electrocution to presumably. Active preamps will sometimes make the earthing sound more noticeable if they boost the higher frequencies. Quote Link to comment Share on other sites More sharing options...
Fat Rich Posted September 27, 2012 Share Posted September 27, 2012 [quote name='lowdowner' timestamp='1348765708' post='1817951'] Oh, so if I ground myself (maybe a cable to a copper pin sunk in the ground) the hum would stop? I'm not going to go to the faff mind, but I'm really pleased to know what's actually going on. Mind you, I *could* be tempted to experiment with a tin foil pointy hat thing - I've seen them on films so they probably work? [/quote] A lot of players just keep their fingers on the strings in between songs. I wouldn't worry about tin foil underpants unless you're in a Spinal Tap tribute band. Quote Link to comment Share on other sites More sharing options...
lowdowner Posted September 27, 2012 Author Share Posted September 27, 2012 [quote name='Fat Rich' timestamp='1348765965' post='1817960'] A lot of players just keep their fingers on the strings in between songs. I wouldn't worry about tin foil underpants unless you're in a Spinal Tap tribute band. [/quote] Now you're taking all the fun out of it! Quote Link to comment Share on other sites More sharing options...
dincz Posted September 27, 2012 Share Posted September 27, 2012 The first thing I'd check is that the bridge is effectively earthed. A multimeter from the bridge to the earth on the output jack should read near enough to zero ohms. Quote Link to comment Share on other sites More sharing options...
uncle psychosis Posted September 27, 2012 Share Posted September 27, 2012 [quote name='lowdowner' timestamp='1348765708' post='1817951'] Oh, so if I ground myself (maybe a cable to a copper pin sunk in the ground) the hum would stop? I'm not going to go to the faff mind, but I'm really pleased to know what's actually going on. Mind you, I *could* be tempted to experiment with a tin foil pointy hat thing - I've seen them on films so they probably work? [/quote] As a quick test to yourself you could try waving your arms around or putting them near a CRT monitor or strip light whilst *not* touching the strings. You should hear the hum change as you do it. Quote Link to comment Share on other sites More sharing options...
Dr M Posted September 27, 2012 Share Posted September 27, 2012 [quote name='uncle psychosis' timestamp='1348764911' post='1817922'] A lot of people get this the wrong way round. The noise stops when you touch the strings because the bass is grounding you, not because you are grounding the bass. The human body is like a big antenna, so by being in close proximity to the electronics of your bass you induce a lot of noise. When you touch the strings you ground yourself and the noise disappears. Humans aren't normally grounded- that's why you occasionally get static shocks and have to wear those ESD bracelets when working on delicate electronics. [/quote] Really? I thought the majority of static shocks were due to you coming into contact with a charged surface, and that surface discharging through you to ground. I understand you can become charged (the anti-static wrist-band thing, but it's also perfectly possible for the human body to act as a very large current sink - essentially, that's all that an electrical earth is. Quote Link to comment Share on other sites More sharing options...
uncle psychosis Posted September 27, 2012 Share Posted September 27, 2012 (edited) Yes, humans can be a path to ground but as a general rule we make pretty poor earth connections. Especially when wearing shoes. Synthetic fibres in our clothes and carpets don't help much either. Edited September 27, 2012 by uncle psychosis Quote Link to comment Share on other sites More sharing options...
Beer of the Bass Posted September 27, 2012 Share Posted September 27, 2012 I've found that this sort of hum (the sort that stops when you touch the strings) diminishes greatly or disappears completely when the control and pickup cavities are shielded with copper foil. Presumably this is because the pickups and wiring are being shielded from my big antenna of a body. Quote Link to comment Share on other sites More sharing options...
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