Effect of coiling power cords?

For convenience much of my gear is plugged into power strips that are, in turn, plugged into a power conditioner or wall socket.  In many cases the power cords are substantially longer than need be, so I've coiled them up into small spools, say 4-5" diameter, and fixed them with zip ties.  I'm doing this in 3 systms - one simple and small, another complex and extremely resolving and an A/V setup.  I'm not a big believer in fancy power cords, but it occurred to me that this is creating several inductors that could conceivably interact with each other, introducing noise, crosstalk, hum, or whatever.  What I'm doing doesn't sound very exotic, yet I can never remember hearing anything about about such effects.  Maybe I haven't been paying close enough attention.  FWIW, I don't have any hum or noise anyplace unless I turn the volume to max on phono inputs.  And even that is teeny.

Anyway, does anybody know anything about what impact coiling the power cords might have?  Whatever the case, it seems like the best practice would be the shortest, straightest run from plug to equipment.  But again, I've never heard anything about real world impact on SQ. Cheers,

Showing 1 response by kijanki

When you wind power cable on toroidal ferrite you create common mode choke, that exhibits inductance for common mode signals (electrical noise current induced in both wires) and no inductance for normal mode signals (currents in opposite directions produce opposing magnetic fields, that cancel).  It is often used to filter out common mode noise without affecting normal signal.  I would think that coiling power cable creates common mode air choke - less efficient (lower inductance) than toroidal core choke, but still effective against electrical noise.  Winding single wire adds inductance, but winding pair of wires (hot and return) doesn't.  This principle is used to create non-inductive wire-wound (bifilar) resistors, where wire is wounded after folding in two (doubled back).  Non-ideal winding might produce some inductance, but I'm not even sure it will be harmful.  If you don't hear any difference then don't worry about it.