David.M Posted June 8, 2014 Posted June 8, 2014 (edited) Wondering if anyone can advise if/how I might be able to shield the power cord coming out of my LED turntable lamp so it doesn't affect my phono ICs. The lamp cord is round rubber sheathed about 3-4mm in diameter. Problem I'm having is if it gets within 6-8inches of my phono ICs I get a slight hum which gets louder the closer they get. Having just re-organised all my gear in new racks I would ideally like to run the lamp cord across the back of the gear to it's power point, it doesn't have any affect on any of my power leads or other ICs. Edited June 8, 2014 by David.M
andyr Posted June 8, 2014 Posted June 8, 2014 Wondering if anyone can advise if/how I might be able to shield the power cord coming out of my LED turntable lamp so it doesn't affect my phono ICs. The lamp cord is round rubber sheathed about 3-4mm in diameter. Problem I'm having is if it gets within 6-8inches of my phono ICs I get a slight hum which gets louder the closer they get. Having just re-organised all my gear in new racks I would ideally like to run the lamp cord across the back of the gear to it's power point, it doesn't have any affect on any of my power leads or other ICs. Are your phono ICs unshielded, David? And do you get the hum from the LED lamp when its round rubber cord cross the ICs ... or when it runs parallel to them? Regards, Andy
David.M Posted June 8, 2014 Author Posted June 8, 2014 Andy, I'm guessing my phono ICs are unshielded though they are very close/cross other ICs & the ASR battery supply power cables which don't cause any noise problems, it is only the LED lamp cord giving me grief.
little blue penguin Posted June 8, 2014 Posted June 8, 2014 Is the lamp running from 230VAC directly, or is there a plug in transformer involved?
LogicprObe Posted June 8, 2014 Posted June 8, 2014 Andy, I'm guessing my phono ICs are unshielded though they are very close/cross other ICs & the ASR battery supply power cables which don't cause any noise problems, it is only the LED lamp cord giving me grief. I'm guessing it's the switchmode supply in the lamp sending garbage down the cable. Can't you just get rid of the lamp and get an incandescent one?
andyr Posted June 8, 2014 Posted June 8, 2014 Andy, I'm guessing my phono ICs are unshielded though they are very close/cross other ICs & the ASR battery supply power cables which don't cause any noise problems, it is only the LED lamp cord giving me grief. As LP said, your problem is probably having a LED light there, to start with. But you're asking for it IMO, using unshielded phono cables. The signal voltage from a cartridge is so tiny - even from a MM - that the slightest amount of RFI around (like from your wireless router) will degrade the signal going into the phono stage. Andy
David.M Posted June 8, 2014 Author Posted June 8, 2014 I have it connected at present without a problem, just from a power point which means the cord is on view. If I have to live with that so be it, I just thought someone might have some knowledge as to whether I can wrap the cord with something that will insulate & minimise escaping RFI & thus allow me to route the cord to another power point (which is on a different circuit to my hifi gear).
little blue penguin Posted June 8, 2014 Posted June 8, 2014 Wrap the cord in aluminium tape (or even tin foil) overlapping to achieve total coverage. Wrap a bare copper wire (preferably solid core) around the above for about 200mm or more near the plug end. Connect this copper wire to an earth point. Wrap the sorry looking mess in insulation tape. It won't look pretty, but if it solves the problem you could then look for ways to dress it up. Alternatively shorten the LED power cable and get a shielded extension cord. 1
Sparkle Posted June 8, 2014 Posted June 8, 2014 The Alum foil road worked for me and is CHEAP! Suggestions i have heard but not tried are, wrap in lead instead of alum, as its a better shield and wrapping the alum foil with rubber to "thicken the sound". 1
Krispy Audio Posted June 8, 2014 Posted June 8, 2014 There's a product called Techflex Conductive. It's not cheap, but might be what you're after, is easy to install, and looks professional. 1
David.M Posted June 9, 2014 Author Posted June 9, 2014 Thanks guys, will try the foil/copper wire finished off with Techflex.
David.M Posted June 9, 2014 Author Posted June 9, 2014 Didn't require that much work Logic Problem solved, a visit to Jaycar to get some aluminium tape, a bit of wire to earth the shielding, alligator clip and some black expandable sheathing, all up around $20. With the earthed aluminium shield in place there is now zero interference & the sheathing completely conceals the foil tape. Perfect outcome, thanks for the tips 1
LogicprObe Posted June 9, 2014 Posted June 9, 2014 Good result. (yes.........you don't want people to see your aluminium foil)
Addicted to music Posted June 9, 2014 Posted June 9, 2014 A cheapskate like me would have just turned the lamp off or positioned the wire away from the effected area...
David.M Posted June 9, 2014 Author Posted June 9, 2014 So does the lamp sound better now? when I have time I'll do a DBT & let you know, wouldn't want to mislead
David.M Posted June 10, 2014 Author Posted June 10, 2014 A cheapskate like me would have just turned the lamp off or positioned the wire away from the effected area... The cheapskate in me wouldn't allow me to get rid of it (plus aesthetically & ease of use it is perfect) and the OCD part of me didn't want the cord out in view, so I had no other options 1
Guest Posted July 11, 2014 Posted July 11, 2014 when I have time I'll do a DBT & let you know, wouldn't want to mislead Still waiting patiently here to find out if the lamp sounds better..... Did you do the DBT yet? I probably wouldn't pass an RBT at the moment :lol: Back to the shed.....
David.M Posted July 11, 2014 Author Posted July 11, 2014 Still waiting patiently here to find out if the lamp sounds better..... Did you do the DBT yet? I probably wouldn't pass an RBT at the moment :lol: Back to the shed..... Sounds like your engaged in your own private double BLIND testing right now (or at least laying the ground work!!)
Guest Posted July 11, 2014 Posted July 11, 2014 It's Friday. Couple of* beers in the shed.... You know how it goes..... * the term "couple of" used very loosely..... ^_^
Sub Sonic Posted July 11, 2014 Posted July 11, 2014 when I have time I'll do a DBT & let you know, wouldn't want to mislead At least it'll be an easy blind test, just do it at night and turn the lamp off. :-) SS
Sub Sonic Posted July 11, 2014 Posted July 11, 2014 Hmm, why do all the batten fittings screwed to the foil worry me? :-)
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