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New member Username: MpjcPost Number: 1 Registered: Sep-05 | I have an old system. Kenwood KR 4070 and DUAL 1237. I noticed that I am now getting a distinct hum when playing an LP. If I touch the turntable or arm the hum gets louder. I have checked the ground and it seems to be secure. Any suggestions? Thanks. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 5698 Registered: May-04 | The contacts could be oxidized and require cleaning or there could be a cable that has developed an open circuit. |
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Gold Member Username: DmwileyPost Number: 1079 Registered: Feb-05 | Try reversing the electric cable. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 5706 Registered: May-04 | Try rubbing your tummy while patting your head. |
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Gold Member Username: DmwileyPost Number: 1084 Registered: Feb-05 | Yeah, that just might work. Jan knows everything. Sorry I didn't think of it. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 5710 Registered: May-04 | Thank you, Wiley. Here I thought you weren't paying attention. |
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New member Username: MpjcPost Number: 2 Registered: Sep-05 | I just tried the tummy and head technique but without music it's just too darn difficult. I did clean the contacts and that helped. Any tricks on what works best when doing that? |
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Silver Member Username: Frank_abelaBerkshire UK Post Number: 889 Registered: Sep-04 | As Dale suggested, if you have a figure of eight cable, or can plug the turntable into the wall in two ways, then try the other way. I have had different results with unearthed kit (unearthed electrically) that has just a 2-pin electric plug. Regards, Frank. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 5725 Registered: May-04 | http://www.dual-reference.com/index.html Dual's have lots of places where there are breaks in the connections. These all tend to oxidize over time; all of which can cause grounding problems. If cleaning the connectors helped, the table probably just needs a good thorough cleaning from the catridge connectors through to the table leads. If this is a table/receiver which has remained plugged in as is for a long time, this is most likely your problem. AC plugs do not need to be reversed if they didn't cause a ground hum in the first place. If you had no problem with hum when the table was originally plugged in, then you might as well rub your tummy. It will do as much good as reversing the AC plug. Though cleaning the AC also plug might help. If this table has been set up recently and you discovered the hum when you first turned the table on, try reversing the plug. It costs nothing and can do no harm on a synchronous motor. However, I do believe you will find a complete cleaning to be more effective than any other route. Wiley is in a disagreeable mood, so I'm sure he'll disagree; though I doubt he has ever seen a Dual table let alone seen the problems and solutions laid out in the link I provided. |
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Gold Member Username: DmwileyPost Number: 1087 Registered: Feb-05 | Frank, thank you very much. I owe you one. |
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Silver Member Username: Frank_abelaBerkshire UK Post Number: 893 Registered: Sep-04 | Dale, no you don't. I have observed that with cheaper cd players with a figure of eight plug, if I trace my finger on the chassis of the player I will get a very small electric charge with the plug in one way and no charge with it in the other way. This is almost always the case (and very surprising indeed). Michael's experience could be the same. Mike That said, it could also be one of the many contacts in the Dual. I took apart a Dual 112S (I think) from the 70s the other week and had to rewire part of it because the connections had perished. Be careful if you undertake this work since there is high voltage in the deck! Regards, Frank. |