Grounding issues?

giovanni

giovanni

Well-known member
Hey guys, here's an anecdote: I went to Guitar Center in San Francisco yesterday and tried a wonderful custom shop Tele (50-51 blackguard pickups) with a factory Deluxe Reverb. I cranked it up and played for like an hour and realized something horrible. The level of hum I experience in my house is off the chart compared to the almost non existent noise at the GC (and they have all kinds of lighting in there). So I decided to ask the folks at GC and one of them suggested that it could be that the house itself is not properly grounded. That came to me as a surprise because when I have experienced grounding issues in houses in the past, I noticed that you can get shocked here and there and it's generally unsafe/possibly not up to code (the house was renovated in 2016)? I am no expert on any of this so I was wondering if any of you guys had any experience with high levels of hum and what to do about it (I already use a power conditioner strip). The timing of this is quite perfect because we are going to start a renovation in our new place soon so if there's anything I should do to prevent hum, now's the time (I already requested a separate breaker for the music room).

Just for reference, here's a clip recorded with my Novo with Fralin P90, into the KoT (yellow side only) and into my TK Imperial MKII (forgive the sloppy playing). Audio taken with my iPhone. The hum is noticeable although it doesn't feel as loud or annoying in the recording as when I am in the room (maybe it's b/c of the iPhone compression).

https://soundcloud.com/giovanni-x-botta%2Fjulian-lage-etude-6
 
Have you tried the amp on different circuits in the house? If anything mechanical (refrigerator, hurnace, etc..) has a transformer it can cause hum on the circuit. My "music room" picks up noise like that from my furnace. Heck, I happen to have about 100 wind turbines all within a 3 square mile area around our little town. During certain times of day my humbuckers can sound like a single coil. I tried a battery powered amp in my house and outside to verify and it makes a humming noise as well. I take it to my parents house 30 miles away and no noise. So regardless of what the power company says I think those things generate some sort of frequency interference.
 
As already suggested, you could plug the amp into different outlets and see if the hum goes away. You can also check to see if the outlets you’re using are actually grounded. A quick an easy way is with a three prong tester.

Limited-time deal: Southwire 40022S GFCI Receptacle Tester https://www.amazon.com/dp/B07HB2J3ZG/ref=cm_sw_r_cp_api_i_dl_7NZHRX7AH97XKH2CHDA4

Or… you can test the outlet with a multimeter. Properly set your multimeter to read at least 120 ac volts. Red probe small slot, black probe large slot. Should give you a reading of wall voltage. Usually around 120 volts. Now, take your black probe and stick it in the u shaped ground slot and leave your red probe in the small (hot) slot. You should get relatively the same voltage reading. If not, then the outlet is not properly grounded.
 
I think I can rule out radio interference because I tried my mustang micro which is battery powered and I don’t think the hum was as much (gotta double check tho).
 
These issues are tough.

Not sure if the dedicated breaker or sub-panel will help.
You'll still be sharing the same ground, but you'll get a dedicated neutral back to the main panel which could really help. :unsure:

In this house, I can hear my washing machine run from 2 rooms away by angling the Tele towards it.
 
I have an idea. Kick your wife, kids and roomates out of the house for an afternoon and turn off every breaker except the one that services the room you plug your amp into.

You could take a sound clip of the buzz before and after using your phone.
 
Three important connections wrt ground: service drop connection (from transformer to meter), breaker box, or the wall receptacle. If the problem is house-wide it is likely the breaker box or service drop connection. The service drop connection is usually damaged when something heavy hits the service drop and is easy to see, the breaker box is usually some issue with the ground rod (corrosion, loose wire clamp, rod resistance > 25R).
 
One thing I forgot to add: the hum doesn’t diminish if I touch the guitar strings. I have definitely experienced the opposite in other places (in Italy for example at my parents house). Could this be a sign of a grounding problem with the entire house?
Also I get no hum with humbuckers or in positions 2/4 on a strat. But I assume that just means the noise comes from EM fields.
 
giovanni said:
Hey guys, here's an anecdote: I went to Guitar Center in San Francisco yesterday and tried a wonderful custom shop Tele (50-51 blackguard pickups) with a factory Deluxe Reverb. I cranked it up and played for like an hour and realized something horrible. The level of hum I experience in my house is off the chart compared to the almost non existent noise at the GC (and they have all kinds of lighting in there). So I decided to ask the folks at GC and one of them suggested that it could be that the house itself is not properly grounded. That came to me as a surprise because when I have experienced grounding issues in houses in the past, I noticed that you can get shocked here and there and it's generally unsafe/possibly not up to code (the house was renovated in 2016)? I am no expert on any of this so I was wondering if any of you guys had any experience with high levels of hum and what to do about it (I already use a power conditioner strip). The timing of this is quite perfect because we are going to start a renovation in our new place soon so if there's anything I should do to prevent hum, now's the time (I already requested a separate breaker for the music room).

Just for reference, here's a clip recorded with my Novo with Fralin P90, into the KoT (yellow side only) and into my TK Imperial MKII (forgive the sloppy playing). Audio taken with my iPhone. The hum is noticeable although it doesn't feel as loud or annoying in the recording as when I am in the room (maybe it's b/c of the iPhone compression).

https://soundcloud.com/giovanni-x-botta%2Fjulian-lage-etude-6
Click to expand...
I have zero input on your grounding issue but am beyond impressed that anyone would attempt anything by Julian Lage, kudos and great playing!
 
MichaelW said:
I have zero input on your grounding issue but am beyond impressed that anyone would attempt anything by Julian Lage, kudos and great playing!
Click to expand...
Thank you! I really appreciate the comment! I’ve been studying that etude for months. It’s a beast!
 
I've been watching a few Psionic Audio clips on Youtube lately - he's an amp repair guy. I build amps so I find his stuff interesting. One thing he often mentions is that so many amps have loose jack sockets, speaker sockets, transformer bolts, pot nuts - basically every bolt or screw might be loose. Thing is most amps ground the circuit through these connections. By making sure every connection is nice and tight you can reduce the hum in your amp significantly.

It's something I notice when trying other amps. All of my amps are built by me, and I am fastidious about grounding, making sure everything is tight, etc. My amps are generally extremely quiet because I avoid ground loops and now I guess because everything is tight. I don't star ground, but use one ground for the preamp and one for the power amp and bias. The AC cable always gets its own ground because that is the code. It's not that difficult and if you pay attention to grounding, lead dress and separation of AC and DC you can get a very quiet amp. Until you plug in a guitar with P90s. :)
 
I feel your pain. When I play my Strat I have to sit facing one specific spot in my room otherwise the buzzing can get out of control. Might not be a grounding issue necessarily but it's still a pain in the ass, and when my washing machine/dryer kicks on I can actually hear it in my signal for a little bit.
I did buy a power conditioner for my amp and pedalboard and I found that to actually be pretty helpful. It doesn't eliminate the noise entirely, but it seems to help mitigate a lot of the extra stuff that I was getting prior to that.
 
jwyles90 said:
I feel your pain. When I play my Strat I have to sit facing one specific spot in my room otherwise the buzzing can get out of control. Might not be a grounding issue necessarily but it's still a pain in the ass, and when my washing machine/dryer kicks on I can actually hear it in my signal for a little bit.
I did buy a power conditioner for my amp and pedalboard and I found that to actually be pretty helpful. It doesn't eliminate the noise entirely, but it seems to help mitigate a lot of the extra stuff that I was getting prior to that.
Click to expand...
Which power conditioner are you using?
 
I have a Furman power strip that’s supposed to do the same thing (?). Honestly I haven’t really noticed a massive difference but I also haven’t tried recording and A/B testing.
 
giovanni said:
I have a Furman power strip that’s supposed to do the same thing (?). Honestly I haven’t really noticed a massive difference but I also haven’t tried recording and A/B testing.
Click to expand...
Apparently, there's a difference between a power strip and a power conditioner? But yea, I will agree that it doesn't make a massive difference but it does seem to mitigate some noise that I was dealing with prior to getting one.
 
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