Overwhelming ground hum without humbusters

Whenever you have ANY rig that have effects in the front of the amp and in the fX loop of the amp or A/C powered effects into the front of the amp you are usually going to have ground loops.

Mark


I have a lexicon mpx g2 and I use it for a long time with many amp in 4cm and I never had ground loop with it! In hi gain and loud volume...
I have now an FX8 and I have hum or hiss with a cornford mk50h 2 in moderated hi gain... No problem with the lexicon in thé same configuration. The FX8 is a fantastic unit and with the humbuster cables it works perfectly for my happyness...

I'm not a technician but Fractal could take a look about the mpx g2 concerning 4cm and ground hiss and hum or explain me why it works well and not the FX8...
 
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I have a lexicon mpx g2 and I use it for a long time with many amp in 4cm and I never had ground loop with it! In hi gain and loud volume...
I have now an FX8 and I have hum or hiss with a cornford mk50h 2 in moderated hi gain... No problem with the lexicon in thé same configuration. The FX8 is a fantastic unit and with the humbuster cables it works perfectly for my happyness...

I'm not a technician but Fractal could take a look about the mpx g2 concerning 4cm and ground hiss and hum or explain me why it works well and not the FX8...
Can you post a clip of the noise you're getting? It's not clear from your description whether you have hum or hiss. (Example: there's no such thing as ground hiss.)
 
Right on!
What amp are you using? This way the next guy with that amp will know that he should order the cables at the same time.

this was with laney ironheart 120H.
tried also with peavey 6505+ in the same rehearsal room, pretty much the same amount of hum.
 
Funny thing about noise........

The first two nights that I used my FX8 with my Rivera Fandango, I did not have enough hum to bother me. It was there, slightly, but didn't change on either amp channel and it never got any louder when I turned the amp up.

Last night, I tried the FX8 with my Archon 25. I tried the Archon by itself so that I could easily identify any noise issues that I might have.
I had tons of hum. Trying to isolate it did not help much.
I ended up turning part of my cable snake into humbusters. This really helped, but there was still a little bit of hum.
I tried an Ebtech HE-2 and that took care of almost all of my hum with this amp: Ebtech HE-2 2-Channel Stereo Hum Eliminator | Sweetwater.com

When I tried to hook up both amps, I got a crazy motorboating sound from the Archon. That's another thread entirely.........

I unplugged the Archon and left the Rivera plugged in. Now I had tons of hum with the Rivera. This was a serious WTF moment!
I started troubleshooting.
Humbuster cables lowered the hum and noise a little bit, but not enough.
The HE-2 lowered the hum but not enough.
I ended up with a combination of HE-2 and Hum-X (Fandango power cord): Ebtech Hum X Ground Loop Hum Exterminator | Sweetwater.com
Now the amp is dead silent, and the noise floor is so low on the Fandango that I don't even need the Noise Gate block that I had been using.

Before using the Hum-X, I could hear my neighbor's power drill through my speaker.
I'm guessing that my hum on the Fandango was always there, but the Gate block was cutting it off before I was able to notice it.
Riveras are finicky amps, but man does it sound good!
 
I've always wanted to try the new Laneys. I'm a huge Iommi fan.

that's a sweet amp. beautiful cleans, great crunch, nice reverb. I was never able to dig out a proper hi-gain sound with the saturation I wanted, but now with FX8 I've dialed in a tubescreamer in front and boy, it's brutal.
 
Sorry for resurrecting an old post, but I've recently come across this problem with one of my amps. I have a Mesa Mark IV that the FX8 is dead quiet with. I DO use humbuster cables.
But I have a custom, hand built amp, that I really like the sound of and wanted to use. It's an extremely well built amp with good components according to 2 techs that have worked on it. It's a Titan Custom 200. Anyways, I get a 60hz hum with the FX8 plugged into it, 4CM of course....
I tried the steps to isolate the hum as outlined above and it seems that most of it comes in when I plug the send cable into the amp.
Do you guys think it's the effects loop that's the problem, namely the send jack?
But, here's what has me boggled, when not using the FX8, and just plugging a pedal into the loop, the problem doesn't exist. It almost seems as if it is triggered by the send jack, but dependent on the fact that the amps input is connected to the same device (FX8). With the pedal scanario, the input jack has nothing to do with the pedal, it's an independent cord from the guitar. DOUBLE BUT, it doesn't do this with the MESA.
The Titan has a solid state effects loop.

BTW, the hum in the link that was posted above is a 120hz hum. Mine is 60hz as measured by a tuner.
 
I have a Mesa Mark IV that the FX8 is dead quiet with. I DO use humbuster cables.
But I have a custom, hand built amp...I get a 60hz hum with the FX8 plugged into it, 4CM of course....
You get the hum when you change the amp. That suggests that the amp is the problem, not your FX8, because you've already proven that your FX8 can operate noiselessly.



I tried the steps to isolate the hum as outlined above and it seems that most of it comes in when I plug the send cable into the amp.
Sounds like a ground loop.


But, here's what has me boggled, when not using the FX8, and just plugging a pedal into the loop, the problem doesn't exist.
The pedal doesn't get power from a wall outlet, therefore it can't create a ground loop.
 
You get the hum when you change the amp. That suggests that the amp is the problem, not your FX8, because you've already proven that your FX8 can operate noiselessly.

I figured that out already, there's something going on with this effects loop in the amp. The hum isn't loud, it would be unnoticed in a live setting.


Sounds like a ground loop.

agreed- would an Ebtech hum eliminator work on this. Not the HumX, but the Hum Eliminator. My concern is wether or not it will work with humbuster cables....

The pedal doesn't get power from a wall outlet, therefore it can't create a ground loop.

Come to think of it, you are correct, I didn't mention it in my original post, but the pedal I used was being powered by a battery. I did not think to plug it into the wall. I'll try that soon....
 
I use Ebtech Hum X Isolation transformers for these types of problems.

Ebtech isolation transformers are great for issues like this with gear that does not draw high amperage.

Ebtech - Audio Solutions
As mentioned, the 4cm is notorious for creating a ground loop that Humbuster cables will not remove. It only happened on one of my 3-amp heads and set-ups, but it did happen & had me very convmfused at 1st.

I thought “Hey, it’s not happening on my Friedman Runt or Mesa Tc-50” so why is it happening to my Carvin Legacy-3.

Who knows & maybe the all metal chassis of the Legacy was the issue? It was completely fixed by buying & putting an Ebtech Hum-X on the power cord of the Amp to break the (Hum) & ground loop.

Don’t try to mask this issue w/ a noise gate or cables, fix it at the source.

Good luck & I’m sure you’ll fix it fast too....

Peace! X
 
Isolation Transformers work good for this to, it separates the ground Loops between different units amps, fx ,processors. once you add a second unit from then on you can get a ground Loops . This happened a lot in the rack units from the 80s
 
As mentioned, the 4cm is notorious for creating a ground loop that Humbuster cables will not remove. It only happened on one of my 3-amp heads and set-ups, but it did happen & had me very convmfused at 1st.

I thought “Hey, it’s not happening on my Friedman Runt or Mesa Tc-50” so why is it happening to my Carvin Legacy-3.

Who knows & maybe the all metal chassis of the Legacy was the issue? It was completely fixed by buying & putting an Ebtech Hum-X on the power cord of the Amp to break the (Hum) & ground loop.

Don’t try to mask this issue w/ a noise gate or cables, fix it at the source.

Good luck & I’m sure you’ll fix it fast too....

Peace! X

I use a bigger Furman ground isolating power conditioner for amps. I'm not comfortable using the Ebtech for high current devices like amplifiers.
 
I have a little noise when I put the Axe-Fx II in front of my Mark V 25 or in 4CM. What is it exactly? Interference?

 
I have a little noise when I put the Axe-Fx II in front of my Mark V 25 or in 4CM. What is it exactly? Interference?


What happens to the noise when you unplug your guitar cable from the Axe? If it goes away, it's electromagnetic interference being picked up by your guitar or guitar cord.
 
Humbusters are essentially what recording studios do: terminate shields at the generator end and float the shield at the patch panel/mixer input. You want to prevent current from flowing through your signal ground. Humbusters work. I don’t understand the reluctance to use them.
 
Humbusters are essentially what recording studios do: terminate shields at the generator end and float the shield at the patch panel/mixer input. You want to prevent current from flowing through your signal ground. Humbusters work. I don’t understand the reluctance to use them.

FYI - The shield is connected on both ends in the humbuster cable. There is more to it than just floating one of the shield connections.
 
Humbusters are essentially what recording studios do: terminate shields at the generator end and float the shield at the patch panel/mixer input. You want to prevent current from flowing through your signal ground. Humbusters work. I don’t understand the reluctance to use them.
Humbuster technology goes beyond just lifting the ground. It uses specialized hardware in the Axe-Fx outputs to analyze the induced noise and supply a signal to buck that noise.
 
Humbuster technology goes beyond just lifting the ground. It uses specialized hardware in the Axe-Fx outputs to analyze the induced noise and supply a signal to buck that noise.
Sorry, I'm not feeling well. I mistakenly used the term "shield" when I should have used "signal ground."

Since humbusters only work connecting the output of the FX8 to the input of the amp (they only work one direction), there's no noise being "induced" at the FX8 output. I think the likelier explanation is that the FX8 separates signal and power grounds (not shields as I previously said) and likely leaves the signal ground floating at the amp input. There may be something more magical going on, but just doing this would dramatically kill hum as no current could flow through the signal ground.

But I suppose I could be entirely wrong. I wonder if someone from Fractal might weigh in and explain things.
 
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