Output 2 hum problem

TheDirtyRelics

TheDirtyRelics

New Member
I know there have been previous posts about noise/hum but wanted to share my issue just in case it's something different. When I plug Output 2 (standard 1/4 cable) into my amp (front or effects return, either one), I get awful hum. I set my phone in the middle of the room and it's about 56db. The hum happens regardless if my guitar is plugged up or not, regardless of volume. If I plug my guitar up, and crank it up, you can hear the processed signal as expected, but with a layer of hum covering it up until you get pretty loud. I tried another more expensive 1/4 cable and went down to 52db. Do I need humbuster cables? Or is this one of those issues that's probably a light bulb or something in my house causing it? My worry is that when I get to a gig, I want to run stereo to the FOH and stereo to my FRFRs. No clue if this problem would go away at a gig or be worse, or do I need 50ft humbuster cables just in case I need to run those to the board? ugh.... I wish it had 2 sets of XLR out.
 
You probably want a humbuster cable between there FM3 output and the amp input.

They are designed for that purpose.
 
Well I got the cables in. If I plug the humbuster 1/4 cable into my PA, it plays with no hum. If I plug it into the FX Return of my amp, it hums. If I plug it into the front of my amp, no hum. So I got some of the issues fixed but not the main one I needed. Not sure why it only hums on the FX return. It hums even if the FM3 is turned down to zero.
 
Just more info in case anyone needs it... I bought 2 headrush 112 FRFR speakers. Plugged the humbuster cables up (trs end into fm3), still hum. Hit the ground lift button on the back of the headrush speaker, and the noise is 99.9% gone. Works great. Still not sure why it doesn't like my FX return on my amp. Will test more with that later.
 
TheDirtyRelics said:
Well I got the cables in. If I plug the humbuster 1/4 cable into my PA, it plays with no hum. If I plug it into the FX Return of my amp, it hums. If I plug it into the front of my amp, no hum. So I got some of the issues fixed but not the main one I needed. Not sure why it only hums on the FX return. It hums even if the FM3 is turned down to zero.
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Seems to be the solution to my very same problem. Thank you for posting. Now getting some humbuster cables.
 
Maybe also try to connect to another ac circuit with headrush than fm3, i think i read that somewhere in the forum, somebody has solved the problem so.
 
I don't know how many other people have issues with this sorta stuff but you definitely have to play around and try several things. Had practice the other day and the other guitar player used a tube amp. While the tube amp was on, one of my XLR cables caused hum in 1 of my headrush speakers. Tried another XLR cable and went from 1 headrush into the other and fixed it. Also noticed when I stand directly in front of my mixer/poweramp, then I get all kinds of noise/hum. There are fixes for everything I think, but just gotta be ready to roll with it in a live setting and have 2 or 3 alternate wiring setups ready.
 
TheDirtyRelics said:
I don't know how many other people have issues with this sorta stuff but you definitely have to play around and try several things. Had practice the other day and the other guitar player used a tube amp. While the tube amp was on, one of my XLR cables caused hum in 1 of my headrush speakers. Tried another XLR cable and went from 1 headrush into the other and fixed it. Also noticed when I stand directly in front of my mixer/poweramp, then I get all kinds of noise/hum. There are fixes for everything I think, but just gotta be ready to roll with it in a live setting and have 2 or 3 alternate wiring setups ready.
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Does your mixer or Poweramp use a power "brick"? Something that converts AC to DC or steps down the voltage?

I've found some of those to emit a lot of EMI.
 
You don’t say whether the equipment is all on the same AC circuit, but that’s an important part of avoiding 60-cycle hum and ground loops. If lifting the ground helped it sounds like you need to put all items that are interconnected onto the same power strip or confirm all the outlets are on the same circuit.
 
I tend to breakdown noise issues into 3 areas. 1. EMI/RFI 2. Ground loops or bad ground reference 3. Poor or damaged transmission line. If as you move around and the noise increases or decreases then very likely it’s proximity EMI/RFI and then it’s good to figure out whether it’s just your pickups, etc. (especially singlecoils) being especially sensitive. if you can find a quiet spot, that’s your spot. Grounding issues are a whole bag of worms. Mainly I try to keep as much as possible connected to one ground source. Sometimes keeping large transformer driven amps separate can be smart. If there is motorized or heavy duty EMI and lighting on a line then keeping digital gear and even poorly shielded analog gear separate is smart. I usually had better luck with rack gear keeping the housings isolated from each other and let the cabling create the audio ground. There‘s more with grounding and reading electrical engineering literature on grounding and ground referencing is helpful even it some of it scrambles your brains. Finally, making sure all your cabling is in top notch shape is a good thing and can save a bunch of headaches.

There‘s always the “ghost in the machine”. Like there’s a spot (corner) in my house that is close to the houses mains and also where all the cable TV/internet junction that just has much more noise. Also, mixing computer monitors and computers themselves is a modern necessity, but huge issue. Especially in a small room. Poorly shielded switching power supplies are a problem. in a dual or stereo setups sometime lifting an audio ground can work. it’s important to never ever lift a power ground unless you’re a licensed electrician and know what you’re doing. Meaning there’s still a ground just not at the point that was separated.
 
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GitGuy513 said:
I tend to breakdown noise issues into 3 areas. 1. EMI/RFI 2. Ground loops or bad ground reference 3. Poor or damaged transmission line. If as you move around and the noise increases or decreases then very likely it’s proximity EMI/RFI and then it’s good to figure out whether it’s just your pickups, etc. (especially singlecoils) being especially sensitive. if you can find a quiet spot, that’s your spot. Grounding issues are a whole bag of worms. Mainly I try to keep as much as possible connected to one ground source. Sometimes keeping large transformer driven amps separate can be smart. If there is motorized or heavy duty EMI and lighting on a line then keeping digital gear and even poorly shielded analog gear separate is smart. I usually had better luck with rack gear keeping the housings isolated from each other and let the cabling create the audio ground. There‘s more with grounding and reading electrical engineering literature on grounding and ground referencing is helpful even it some of it scrambles your brains. Finally, making sure all your cabling is in top notch shape is a good thing and can save a bunch of headaches.

There‘s always the “ghost in the machine”. Like there’s a spot (corner) in my house that is close to the houses mains and also where all the cable TV/internet junction that just has much more noise. Also, mixing computer monitors and computers themselves is a modern necessity, but huge issue. Especially in a small room. Poorly shielded switching power supplies are a problem. in a dual or stereo setups sometime lifting an audio ground can work. it’s important to never ever lift a power ground unless you’re a licensed electrician and know what you’re doing. Meaning there’s still a ground just not at the point that was separated.
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Good summary.

+1 for keeping chassis isolated from each other in the rack. If all the gear were correctly designed, it wouldn't matter. But they're often not. I use Humfrees on my racks out of habit.

And a big +1 for not lifting power grounds. That's just courting tragedy.
 
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Rex said:
Good summary.

+1 for keeping chassis isolated from each other in the rack. Of all the gear or correctly designed, it won't matter. But they're often not. I use Humfrees on my racks out of habit.

And a big +1 for not lifting power grounds. That's just courting tragedy.
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Thanks! Yeah the HumFrees are good. You’re right if everything was properly engineered it would go a long way to making things less hassle. I neglected to add using a good filtered power junction can be a big help. Even if money is tight the Furman SS-6 (?) can be helpful.

To add to Unix Guy’s comment. Cheap AC to DC power supplies are a problem. Especially the multi outlet or daisy chain deals. If anything with more than 4 outlets was less than $100 US it’s probably not very good. I don’t have experience with some of the pricey (hopefully properly made) power bricks. I made my own 12 outlet with 18volt sources a good many years ago where the AC mains is rectified using high end components and properly filtered and then every DC outlet is transformer isolated, filtered, high quality regulated and housing is shielded properly. That solved just about all my problems especially when I was using a bunch of pedals. I imagine the multiple 100 dollar units that are out there are properly built the same. I actually thought about building them and selling them, but by the time I got to figuring out what would be needed to make it certified other companies were beating me to the market and I dropped it. At the time I didn’t think anyone would spend close to $500 or more for a multi AC to DC supply (which is what I would have probably needed to charge to make any money) but it appears I was wrong.
 
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