Slipperydick Posted August 4, 2015 Share Posted August 4, 2015 [quote name='TimR' timestamp='1438646910' post='2836140'] That is a seriously dangerous suggestion. Do not do that! [/quote][quote name='Norris' timestamp='1438670137' post='2836185'] Oh my goodness. That photo made me cringe. Please stop fannying about and get back in touch with your sparky [/quote] Why ? Cos it isnt earthed or because the polarity is temporarily reversed ? OK, lift the earth wire out of a wired plug as has been suggested/tried. Equally dangerous by your reckoning. Sparky obviously hasnt got a clue, he's only trained in providing a safe earth. Quote Link to comment Share on other sites More sharing options...
cheddatom Posted August 4, 2015 Share Posted August 4, 2015 He already tried disconnecting the earth on the amp plug and it worked?! I have had similar problems in the past. I managed to solve it with an old UPS I had knocking around. They're basically big batteries to keep servers running if you have a power cut, but I use one in between the mains and my amp and the hum is gone! Quote Link to comment Share on other sites More sharing options...
icastle Posted August 4, 2015 Share Posted August 4, 2015 [quote name='Slipperydick' timestamp='1438645578' post='2836135'] If you lightly stroke a metal part of the amp, or your Bass with it powered up do you feel any tingling ? Could you temporarily connect it to the mains using a four way lead, but with the plug upside down, as in the photo, and let us know if it makes any difference ? You will be removing the earth and also reversing the polarity. [attachment=197812:20150803_235517.jpg] [/quote] No no no. Seriously bad thing to do. Not only are you removing the earth but you're ending up with the fuse on the Neutral side where it has no effect whatsoever. The way to approach this is: 1) Take the amp to a mates house and try it there. If it still buzzes then the amp or cabling is faulty - get it repaired. 2) Unplug the fridge and make sure any lights using dimmer switches, fluorescent tubes or transformers are switched off. If the buzz goes then turn the items back on one at a time until you find the culprit. 3) Run an extension lead from upstairs and try that supply instead (or vice versa if you're already upstairs). 4) Get yourself a plug in mains tester - essential bit of kit if you're gigging anyway. 5) If all that fails then get an electrician in, preferably not the one who did the work in the first place. A fresh pair of eyes can often see things clearer. Snipping earth cables, plugging things in back to front and general piddling about with your electric supply is just asking for trouble. Quote Link to comment Share on other sites More sharing options...
Slipperydick Posted August 4, 2015 Share Posted August 4, 2015 (edited) [quote name='icastle' timestamp='1438689531' post='2836376'] No no no. Seriously bad thing to do. Not only are you removing the earth but you're ending up with the fuse on the Neutral side where it has no effect whatsoever. The way to approach this is: 1) Take the amp to a mates house and try it there. If it still buzzes then the amp or cabling is faulty - get it repaired. 2) Unplug the fridge and make sure any lights using dimmer switches, fluorescent tubes or transformers are switched off. If the buzz goes then turn the items back on one at a time until you find the culprit. 3) Run an extension lead from upstairs and try that supply instead (or vice versa if you're already upstairs). 4) Get yourself a plug in mains tester - essential bit of kit if you're gigging anyway. 5) If all that fails then get an electrician in, preferably not the one who did the work in the first place. A fresh pair of eyes can often see things clearer. Snipping earth cables, plugging things in back to front and general piddling about with your electric supply is just asking for trouble. [/quote] As theres no earth to short to, the fuse would have the same effect as in the live side, ie. blow if theres a short. The words to note in my post were Temporary, and 4 way. The 4 way will be fused in the live side anyway. The mains TX in the amp, is effectively the only thing connected to the mains, and although its best practice to connect the inner end of the winding to the neutral, you will find that mains transformers these days have two identical wires for the primary winding, and so it really wont make a difference. I see no one has described exactly how its dangerous, the only danger is that if theres a short to earth, you might get a pisser by touching the earth pin on the plug, but if there was a short to earth, the fuse would have blown whit it plugged in the correct way. Taking it to an amp tech is pointless if it doesnt hum in his place. If disconnecting the earth temporarily stops the hum, it proves where its coming from, if it makes no difference, no harm done... Sometimes reversing the primary winding of the Mains TX makes a difference. Its not general piddling about, its a legitimate test based on my 45 years experience of servicing electronic equipment for a living, just that reversing the plug is easier than the generally accepted method of disconnecting the earth temporarily with moulded plugs, and unlike many on here, I wouldnt recommend that the OP opens the amp to do it. Edited August 4, 2015 by Slipperydick Quote Link to comment Share on other sites More sharing options...
cheddatom Posted August 4, 2015 Share Posted August 4, 2015 [quote name='Slipperydick' timestamp='1438691098' post='2836397'] ...If disconnecting the earth temporarily stops the hum, it proves where its coming from... [/quote] He's already done this! Quote Link to comment Share on other sites More sharing options...
Slipperydick Posted August 4, 2015 Share Posted August 4, 2015 [quote name='cheddatom' timestamp='1438691287' post='2836402'] He's already done this! [/quote] I know, [i][color=#282828][font=helvetica, arial, sans-serif]"We temporally removed the earth from the main fuse, and it stopped"[/font][/color][/i] [color=#282828][font=helvetica, arial, sans-serif]Does that mean at the amp or the consumer unit or what ? It makes a difference.[/font][/color] [color=#282828][font=helvetica, arial, sans-serif]The OP is ignoring any direct questions from myself and from others, which might help with finding an answer to HIS problem. So to be honest. I've kinda lost interest now.[/font][/color] Quote Link to comment Share on other sites More sharing options...
spongebob Posted August 4, 2015 Author Share Posted August 4, 2015 [quote name='Slipperydick' timestamp='1438698843' post='2836489'] [color=#282828][font=helvetica, arial, sans-serif]The OP is ignoring any direct questions from myself and from others, which might help with finding an answer to HIS problem. So to be honest. I've kinda lost interest now.[/font][/color] [/quote] I am not ignoring anything. I have been reading and posting back where I can. I have also thanked posters on the thread for their help and advice. However, I am not an electrician. I took some basic advice when posing the original question, to hopefully gain some insight on here from those with far greater knowledge on the subject than I. That has been achieved. I also found it interesting to allow the thread to run - allow those with said knowledge to discuss it amongst themselves - to see what conclusion could be gained. Quote Link to comment Share on other sites More sharing options...
the boy Posted August 4, 2015 Share Posted August 4, 2015 [quote name='Slipperydick' timestamp='1438474494' post='2834823'] in various envoronments [/quote] You were doing so well...... #1 rule of Internet BIG-I-AM-ING is get your spelling right. Quote Link to comment Share on other sites More sharing options...
Slipperydick Posted August 9, 2015 Share Posted August 9, 2015 [quote name='the boy' timestamp='1438726058' post='2836799'] You were doing so well...... #1 rule of Internet BIG-I-AM-ING is get your spelling right. [/quote] Up yours fellah. Quote Link to comment Share on other sites More sharing options...
the boy Posted August 9, 2015 Share Posted August 9, 2015 [quote name='Slipperydick' timestamp='1439114119' post='2840020'] Up yours fellah. [/quote] lol lol lol, good man. Quote Link to comment Share on other sites More sharing options...
.thumb.jpeg.795def0f48febb3d6ebc9016d16df248.jpeg)
.gif.9ad672bb8b84505709f76b39c8c256ec.gif)
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.