Hi,
the transformer or the cable is the problem because they both generate a magnetic field. (the cable is probably the big problem) The frequency of the railroad is 16.5Hz in Germany. What we hear here as a disturbance are the overtones and their distortions (approx 600hz-5000khz … it is a whir). These disturbances are omnidirectional and no material can stop them, at most bend a little. (except µ-Metal in many thick layers … very expensive) The only solution is distance (approx. 80-100meters) or a magnetic field canceling system. Your cable is basically like our railway line. You can check this with a guitaramp with battery … and then walk away from the generator/cable and hear what happens.
Good luck
Greetings Michael
ffg David let me guess before you post:
The Furman did not fix the problem.
Yep, you’re right on.
Drat.
Getting the distinct feeling there isn’t a solution to this one.
It’s noticeable that the buzz is worse when I hold the guitar, like my body is picking up the interference and passing it on to the guitar. When I touch any of the guitar metalwork, the buzz almost disappears. Not noticeably worse with single coils vs humbuckers.
I am not an electronics/ impedance/ shielding/ balanced vs HiZ expert, and can’t analyze the technical reasons this is happening to you (it’s been explained to me and my eyes are still glazed over–and I’m sure there are people trained in old-school engineering here who could clarify), but I can tell you it happens to lots of people, myself included, from time to time. The guitar plays a large part in it. My Danelectro bari (great sound, except for that hellacious hum when you’re not facing in exactly the right direction) is one of the worst; Teles can be nasty, Strats as well, though you can use the “out of phase” position, if aesthetically compatible with your musical objective, to really cut the buzz. My Kent electric mandola, which is one of the coolest pieces of crap ever made, with its extraordinarily tone-full single coil, also can create a buzz that could saw through an oak log.
But what I’ve had good luck with, when all else fails, is to fix a wire to the, as you say, “metalwork” on the guitar, an alligator clip (or band aid) to the other end and put it in contact with skin… hip, arm, wherever. As you noted, body/ground can really zap the buzz. Give it a try!
Chewy
Thanks Chewy, I agree and I think all of us struggle with some variation of this issue.
The reason for this thread from my point of view is that I seem to have a low level buzz which isn’t entirely typical of the sort of interference we all get from pickups.
It IS quite low level, for clean guitar sounds I can easily gate it out. It becomes a problem with very overdriven and compressed tones.
It affects ALL guitars more or less equally
It can’t be tuned out by moving around the room or rotating the player.
It’s not a ground/earth loop issue, it affects guitar amps which aren’t even connected to the studio mains
It’s definitely related to grounding the player to the guitar, like you I’ve had some success grounding the guitar to the player with a wrist band.
I guess I was just hoping there might be an actual fix for the problem…
Yes I was right on.
Again, you touch the strings and it gets quieter, it is ground related.
Are you on a clean guitar patch, or heavy distortion when you hear the hum?
If it is distortion, a certain amount will be normal, and you can use a gate to reduce it.
However if the hum occurs in a clean patch, there are several steps you can take to minimize the hum.
Also, from my last post, did you try the 360° rotation I mentioned?
It should get quieter at one point, and quieter again at 180° from that point. This has to do with magnetic induction.
I also asked if you could measure between 2 grounds if you are using more than one AC plug, and do you get 0.000 volts?
If your answer is yes, I can give you a few steps to minimize the hum.
Thanks for this. Please see my reply above yesterday to Chewy.
No, rotating the player doesn’t help. Yes, grounding the player to guitar helps. Yes, the buzz is always there (same for any guitar) but obviously worse for overdriven/compressed tones. It’s easily gated out for clean tones, more troublesome for the heavier tones.
It’s not a ground loop as such, the buzz is there with a simple setup of guitar and amp.
Electrical resistance to true ground potential - I guess I could test this by driving a copper stake in the ground and checking resistance to mains ground? As I understand it, in the UK the mains ground originates at the supply pole which is close to the studio building, there is certainly a thick cable running down the pole (apart from the supply cable to the building).
Academically, it might be interesting to see what you’d get with a laptop running off of its battery, and recording through a bus-powered interface such as the UR-22, thereby removing it from house AC completely. I’d lend you one of my URs, but the commute’s impractical! 
You COULD , crummy quality aside, and just for the purposes of knocking down troubleshooting variables, try going direct into your MacBook. For what it’s worth…
Chewy
Hmmm good call Chewy, I have an Audient ID4 which will run on USB power (without phantom powering enabled), I’ll try it
Well, that was worthwhile, in fact I’d say it’s nailed where the noise is coming from.
The culprit is the mains supply step-down transformer, located on a pole about 8m from one end of the studio building.
I devised a portable test rig consisting of my MacBook Pro running off battery, Audient ID14 powered by USB and a Strat, monitoring on headphones.
The noise got worse the nearer I got to the pole. Standing underneath it was strongest. Going to the farthest boundary away from the pole, the noise had almost gone.
Contrary to what I said earlier, it IS possible to reduce the interference by rotating the player, but it’s a very narrow node.
I’m going to get onto the power distribution company and pester them for a fix - I’m hoping they are bound by regulations about radiated EM interference.
Thanks to all who weighed in on this one.
I don’t know exactly how, but now you know the direction some Faraday cage like scheiding might be possible. You could try a small Alu foil or chicken mesh shield between the guitar and the pole to see if it has any effect. The shield might need grounding but I am far from an expert. More a marvel comic book reader in my younger days.
If a small scream works a large one is easy to make for between the pole and the guitar player.
Cheers and good luck!
Thanks vinark it may come to that if the power co can’t/won’t do anything.
I like the idea of a small scream, in fact I tried that already but it only helped me feel a bit better, didn’t fix the problem…
A super-stong G5 antenna which transmits Covid-19 in your area?
(Sorry, couldn’t resist)
Sorry 'bout your troubles.
Fredo
I blame Brexit
No, David, no. It’s the bats. BATS!
Chewy