Miguello Posted September 3, 2016 Share Posted September 3, 2016 I was trying to narrow down where a nasty humming noise was coming from while my Epi SG was hooked up and playable. I noticed this humming was worse when the volume was all the way up OR down, and would cut off by at least half when I would touch the metal edge of my desk. It's a silver metal frame with a frosted glass top, and I have a light hooked up along the back edge, that makes the top glow, and lights up underneath for indirect lighting. I reached under the desk and clicked off the light. The noise completely disappeared. Do fluorescent light ballasts put out a magnetic field of some sort? I have never noticed this with any other guitars? The amp is a Pignose G-40V tube amp with a single ten inch speaker. When the volume all the way down on the guitar, I am picking up a local radio station. I only noticed this when I was living in high rise buildings for a while. As soon as the volume hits one, it's gone, and a nasty interference pops up if I touch the strings and the edge of the desk at the same time. The light is still off. Hopefully I can lose all of this electronic weirdness. Link to comment Share on other sites More sharing options...
capmaster Posted September 3, 2016 Share Posted September 3, 2016 ... Do fluorescent light ballasts put out a magnetic field of some sort? I have never noticed this with any other guitars? ... When the volume all the way down on the guitar, I am picking up a local radio station. I only noticed this when I was living in high rise buildings for a while. As soon as the volume hits one, it's gone, and a nasty interference pops up if I touch the strings and the edge of the desk at the same time. The light is still off. ... Fluorescent light ballasts are infamous for electromagnetic interference, same as phase controlled modulators used for dimmers and primary switch-mode power supplies replacing those built around common mains transformers. The radio demodulation issue has also occurred since guitar amplification started. This is due to rectifier effects of amp input stages in conjunction with signal sources acting as antennas. Unbalanced signal paths are prone to pick up those interferences, and as far as susceptible lines are considered, humbucking pickups are of no help. High rise buildings may contain lots of steel, and RF levels increasing due to height above the ground may aggravate the problem. Then there likely are lots of other sources of electromagnetic interference in close vicinity. Furthermore the electrical ground level within large buildings becomes more or less floating with height. I once experienced a bad buzz intermittently appearing in a village in the street I lived. It was there 24/7 and even interfering with the phone line. A six-hour evaluation by the telephone company lead to the result that the suppressor capacitor of a neighbour's chest freezer had gone bad. Some of these components are even infamous for exploding, partly happening in HiFi and studio gear: From a Revox amplifier: From a Tandberg tape recorder: Link to comment Share on other sites More sharing options...
Johnny 6 String Posted September 3, 2016 Share Posted September 3, 2016 I was trying to narrow down where a nasty humming noise was coming from while my Epi SG was hooked up and playable. I noticed this humming was worse when the volume was all the way up OR down, and would cut off by at least half when I would touch the metal edge of my desk. It's a silver metal frame with a frosted glass top, and I have a light hooked up along the back edge, that makes the top glow, and lights up underneath for indirect lighting. I reached under the desk and clicked off the light. The noise completely disappeared. Do fluorescent light ballasts put out a magnetic field of some sort? I have never noticed this with any other guitars? The amp is a Pignose G-40V tube amp with a single ten inch speaker. When the volume all the way down on the guitar, I am picking up a local radio station. I only noticed this when I was living in high rise buildings for a while. As soon as the volume hits one, it's gone, and a nasty interference pops up if I touch the strings and the edge of the desk at the same time. The light is still off. Hopefully I can lose all of this electronic weirdness. As Cap said all sorts of electric/electronic things can contribute to buzz and interference, I've also found that cheaper cords/cables can increase the antennae like experience with amps and radio stations. Link to comment Share on other sites More sharing options...
Miguello Posted September 3, 2016 Author Share Posted September 3, 2016 As Cap said all sorts of electric/electronic things can contribute to buzz and interference, I've also found that cheaper cords/cables can increase the antennae like experience with amps and radio stations. I've got those cables you custom make to length, and supposedly back when I bought them they were the hottest thing going. Thin hard coax, with screw together ends. They have have proved way more durable than pre made cable with traditional fat insulation. They have been put through the ringer, and still hold up. I don't have any of the old fat cables save for a few short between pedal lengths. At the time I remember them putting out better sound, and I guess they still do? The name was two capital letters with a & between them. G&L? D&L? I don't know if they're even still made. Link to comment Share on other sites More sharing options...
Eddie K Posted September 10, 2016 Share Posted September 10, 2016 All my cables are George L's except for one application. If I use one, with my LR Baggs RT equipped Martin HD28, between the pickup/guitar and the external Para DI all I get is radio interference. In all other applications they are great. Link to comment Share on other sites More sharing options...
Miguello Posted September 10, 2016 Author Share Posted September 10, 2016 A George L is my main guitar to effects or guitar to amp cable. It's outlasted every cable I've ever bought. Mine is the old chrome ends and black hard small diameter stiff cable. Awesome sound difference that I really noticed back then, and it's about 15 years old now. I've had other cables go bad so often that I just throw them out rather than mess with repairing them. some of them only lasted a month or two, and I don't play gigs. All home use.This cable, perfect and bombproof. "Somewhere" I have all my patch cables, that are also George L. They're probably in the same box as my Strat pickguard, old Strat pickups, spare bridges, etc etc etc. I wish I could find them, but I have a LOT of stuff here. They could be anywhere, sigh. Link to comment Share on other sites More sharing options...
Little Jerry Posted September 12, 2016 Share Posted September 12, 2016 I have a similar problem in my home using my Epiphone Riviera Custom P93. I initially replaced all of my cables with premium store bought cables, but that didn't help much. The luthier I use told me that electromagnetic interference is normal and varies with the severity of conditions that cause the interference. He also told me that the P90 pickups on my guitar are sensitive to electromagnetic interference. I tried my son's Strat that has noiseless pickups through my amp, which reduced, but did not eliminate the hum. Link to comment Share on other sites More sharing options...
Miguello Posted September 13, 2016 Author Share Posted September 13, 2016 I've noticed it's not a problem really, unless I am touching any metal on the guitar, and reach for the computer mouse, which causes me to touch the edge of the desk. Single coils hum almost always, and it tends to go away or gets hidden once you start playing. I just live with it on my Strat. It's worth it for the sound. Link to comment Share on other sites More sharing options...
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