Rusco Posted October 21, 2019 Share Posted October 21, 2019 (edited) Hey, hoping someone can help or give me some pointers. My amp has a nasty mains ring / earth type hum when we play at our local pub. It only happens in this one pub and we all suffer with it.. leading me to assume it’s perhaps an earth issue with their sockets. This happens no matter what bass I use but does seem more pronounced with my Flea Jazz. I can reduce it a bit by eq’ing the high frequencies down but it never goes. It does significantly reduce when I touch the strings. The amp is plugged directly into the socket and bass directly into amp so nothing else in the paths. Amp: Markbass CMD121P + NY121 Basses: Sringray, US P, Flea Jazz, BB424, Tanglewater Contemporary J I use either a cable or Boss wireless but makes no difference which. The pub socket is the only variable so I’m reasonably sure it’s this however getting them to look at their electrics is unrealistic, so wondered if anyone has any suggestions how I can overcome or at least minimise this through setup or a clever bit kit ?. Thanks in advance! Edited October 21, 2019 by Rusco Quote Link to comment Share on other sites More sharing options...
Deedee Posted October 21, 2019 Share Posted October 21, 2019 I bought one of these to overcome power noise and power line interference at home and found an immediate improvement. May be worth having in your gig bag for those venues with such problems. https://www.amazon.co.uk/Tacima-6-Way-Mains-Conditioner-black/dp/B00UB0G4DQ/ref=cm_cr_arp_d_product_top?ie=UTF8 Quote Link to comment Share on other sites More sharing options...
NancyJohnson Posted October 21, 2019 Share Posted October 21, 2019 Recommended (or otherwise), while it's feasible there's an issue with the wiring at the pub itself, this can be compounded (if my terminology is correct) by having multiple earths on the same loop or even running effects. Quick question. If you're playing with a guitarist or keyboardist, do their amps suffer the same fate or just yours? Insofar as a solution goes, a quick look online shows that your Markbass head has ground loop switch. Try it. It will simply take the earth out of your power lineage and correct things. Also, rightly or wrongly, you could just carry a spare kettle lead with just the live and neutral connected (just snip off the earth and put some heat-shrink over the end. Quote Link to comment Share on other sites More sharing options...
goingdownslow Posted October 21, 2019 Share Posted October 21, 2019 9 minutes ago, NancyJohnson said: Also, rightly or wrongly, you could just carry a spare kettle lead with just the live and neutral connected (just snip off the earth and put some heat-shrink over the end. Wrongly. Never remove the protective earth connection, the chances are it could end up being used on some faulty equipment. 1 Quote Link to comment Share on other sites More sharing options...
John Cribbin Posted October 21, 2019 Share Posted October 21, 2019 At the very least I'd fork out £8 for one of these at Screwfix. I'd want to know the power supply is safe before anything else .... 1 1 Quote Link to comment Share on other sites More sharing options...
jrixn1 Posted October 21, 2019 Share Posted October 21, 2019 9 hours ago, Rusco said: The amp is plugged directly into the socket and bass directly into amp so nothing else in the paths. 34 minutes ago, NancyJohnson said: your Markbass head has ground loop switch. Try it. It will simply take the earth out of your power lineage and correct things. The ground lift switch is for the DI output, not the power. You use it if there is hum caused by a ground loop, which is when two pieces of equipment (a bass amp and a mixing desk) are connected together (with an XLR cable) but each is connected to different grounds. The ground lift will disconnect one of the pins in the XLR, breaking the loop. However, I don't think this is what this post is describing. Quote Link to comment Share on other sites More sharing options...
KiOgon Posted October 21, 2019 Share Posted October 21, 2019 As suggested above - a few quid spent on a simple plug in mains tester could save lives. If any pub or other venue has dodgy mains wiring they shouldn't be in business! Needs sorting urgently. 1 Quote Link to comment Share on other sites More sharing options...
Mottlefeeder Posted October 21, 2019 Share Posted October 21, 2019 There may be other possible causes that could be investigated, for example, interference from fluorescent lights close to where you play, or gaming machines on the same circuit etc. Try plugging in elsewhere in the pub and see if you have the same problem. David Quote Link to comment Share on other sites More sharing options...
NancyJohnson Posted October 21, 2019 Share Posted October 21, 2019 8 hours ago, goingdownslow said: Wrongly. Never remove the protective earth connection, the chances are it could end up being used on some faulty equipment. Or just mark it up 'pub check'. Really no harm in trying. 1 Quote Link to comment Share on other sites More sharing options...
mcnach Posted October 22, 2019 Share Posted October 22, 2019 On 21/10/2019 at 04:00, Rusco said: Hey, hoping someone can help or give me some pointers. My amp has a nasty mains ring / earth type hum when we play at our local pub. It only happens in this one pub and we all suffer with it.. leading me to assume it’s perhaps an earth issue with their sockets. This happens no matter what bass I use but does seem more pronounced with my Flea Jazz. I can reduce it a bit by eq’ing the high frequencies down but it never goes. It does significantly reduce when I touch the strings. The amp is plugged directly into the socket and bass directly into amp so nothing else in the paths. Amp: Markbass CMD121P + NY121 Basses: Sringray, US P, Flea Jazz, BB424, Tanglewater Contemporary J I use either a cable or Boss wireless but makes no difference which. The pub socket is the only variable so I’m reasonably sure it’s this however getting them to look at their electrics is unrealistic, so wondered if anyone has any suggestions how I can overcome or at least minimise this through setup or a clever bit kit ?. Thanks in advance! I know you described it as mains hum but seeing that your single coil pickup bass is the worst there... are you sure it's not interference of some sort? In pubs you may get all kinds of weird and wonderful lighting equipment that can be quite noisy. Hard to check without going around turning things on and off, which I doubt they'll let you... but you can have a look around for fluorescent strips and dimmers which are some of the worst culprits. If that's the issue, there's little you can do except shield your instruments the best you can and accept there will be some noise especially with single coil pickups. The mains tester suggested is always a good idea regardless. Quote Link to comment Share on other sites More sharing options...
Stub Mandrel Posted October 22, 2019 Share Posted October 22, 2019 21 hours ago, NancyJohnson said: On 21/10/2019 at 13:01, goingdownslow said: Wrongly. Never remove the protective earth connection, the chances are it could end up being used on some faulty equipment. Or just mark it up 'pub check'. Really no harm in trying. As someone, somewhere else pointed out during a similar discussion: "At some point you will loan or sell your stuff - or die; will the next user know what 'custom' modifications you have made that affect safety?" Quote Link to comment Share on other sites More sharing options...
NancyJohnson Posted October 22, 2019 Share Posted October 22, 2019 2 hours ago, Stub Mandrel said: As someone, somewhere else pointed out during a similar discussion: "At some point you will loan or sell your stuff - or die; will the next user know what 'custom' modifications you have made that affect safety?" Good grief, have some perspective. It's a kettle lead; try it once, if it doesn't work, or solve the issue, throw it away. I'm not advocating openibg the amp and rewiring it. Lest we forget, most of Europe operate electrical systems on a non-earth, two core cable systems. Quote Link to comment Share on other sites More sharing options...
Stub Mandrel Posted October 22, 2019 Share Posted October 22, 2019 2 minutes ago, NancyJohnson said: Lest we forget, most of Europe operate electrical systems on a non-earth, two core cable systems. Red herring. Europlugs can only be fitted to class II (double insulated) products. Amps with an earthed metal chassis are unlikely to be class II. 1 Quote Link to comment Share on other sites More sharing options...
afterimage Posted October 22, 2019 Share Posted October 22, 2019 Hi the Tacmina is a good mains conditioner Or hum elimator is useful Quote Link to comment Share on other sites More sharing options...
Rusco Posted October 26, 2019 Author Share Posted October 26, 2019 Many thanks for all of the replies and suggestions!!. A few answers to some of the questions.. Yep the guitar players have the same issue. Earth-less kettle lead is an idea just as a way of proving or ruling our mains. I wouldn’t run with it but as a diagnostic idea it’s ok.. if I can find an old spare one without a moulded plug 🤔 I did consider interference as the issue improves when touching the strings. Also when using the Boss wireless the bass is obviously completely isolated from the amp. That said.. I tried wirelessly wondering around the whole, quite large, pub and it made no noticeable difference. We are back there this Wednesday so I’ll try some other sockets and look for anything obvious that may cause interference. Cheers Quote Link to comment Share on other sites More sharing options...
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