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DI Box And Hum?
Old 29th January 2013
  #1
Gear Head
 
🎧 10 years
DI Box And Hum?

Hi guys,

Bit confused about something and would love a bit of advice.

So with my amp I get a bit of hum when the gain is cranked which I'm alright with. In the final production of a tune you can't hear it at all and everythings cool but I always wondered about getting rid of it, just for interest's sake. I'm new to using a DI box. I've never had to get rid of it cause as I said, you can't hear it with the other instruments playing.

My housemate works at an AV company and just brought back a nice DI box so I decided to have a play with it tonight.

I whacked my guitar cable in the input and looked at the back, it's only got an XLR output?

First question - for this to work properly, do I need to get an XLR -> 1/4 jack cable to go into the amp?

There's another output for a 1/4'' jack called "Link" which I put a patch cable into and then into the amp and hey presto, it's all working nicely...the guitar is playing through the amp like normal........but still with hum.

What's up with that? I flicked the switches on the box (there's an Earth switch and Power switch) but still the amp is humming? I was under the impression that a simple flip of polarity would get rid of the hum. There's no change whatsoever when I flip the switch...nothing at all.

The box takes a 9v battery that could be the issue but when I flip the power button on, its got a nice blue light showing so I think the battery is alright..

Am I missing something fundemental here?
Old 30th January 2013
  #2
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
Quote:
Originally Posted by RileyAWA ➑️
Hi guys,

Bit confused about something and would love a bit of advice.

So with my amp I get a bit of hum when the gain is cranked which I'm alright with. In the final production of a tune you can't hear it at all and everythings cool but I always wondered about getting rid of it, just for interest's sake. I'm new to using a DI box. I've never had to get rid of it cause as I said, you can't hear it with the other instruments playing.

My housemate works at an AV company and just brought back a nice DI box so I decided to have a play with it tonight.

I whacked my guitar cable in the input and looked at the back, it's only got an XLR output?

First question - for this to work properly, do I need to get an XLR -> 1/4 jack cable to go into the amp?

There's another output for a 1/4'' jack called "Link" which I put a patch cable into and then into the amp and hey presto, it's all working nicely...the guitar is playing through the amp like normal........but still with hum.

What's up with that? I flicked the switches on the box (there's an Earth switch and Power switch) but still the amp is humming? I was under the impression that a simple flip of polarity would get rid of the hum. There's no change whatsoever when I flip the switch...nothing at all.

The box takes a 9v battery that could be the issue but when I flip the power button on, its got a nice blue light showing so I think the battery is alright..

Am I missing something fundemental here?
Yes, you're missing something fundamental.

You don't need a DI box to plug into your amp, it won't do anything for you.

A DI box is used to run the unbalanced output of an instrument (usually high impedance) into a balanced mic level input. It will generally have two 1/4 inch jacks on the front to allow daisy chaining the signal to an amp (without affecting it) and an XLR on the back to connect to the mic input. All but the very cheapest boxes will also have a ground lift switch (usually next to the XLR) to eliminate ground loops between the mic input (on the preamp or console) and the instrument amp. Better boxes may also have a pad switch to allow the box to be connected in parallel with the speaker output of an amp without overloading the box and/or mic input.

By itself a DI box won't have any effect on hum being generated between your guitar and amp although it can affect ground loop hum between the amp and mic input.
Old 30th January 2013
  #3
Here for the gear
 
808 Jake's Avatar
 
🎧 5 years
DI your guitar into your DAW of choice if you want to use amp modeling software to minimize hum--- completely cutting out your amp, and any mics you may have.

But you have those things, so you should use them!

It sounds like all you need to do is keep recording your amp the way you have been, and add a very basic gate plug in (stock in your daw) to your guitar track. Set the threshold above the natural noise level of the amp, and boom-- your noise will be gone.

Remember though that a little noise is a good thing sometimes. It's how you know it's real!!
Old 30th January 2013 | Show parent
  #4
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
Quote:
Originally Posted by 808 Jake ➑️
DI your guitar into your DAW of choice if you want to use amp modeling software to minimize hum--- completely cutting out your amp, and any mics you may have.
Why would he want to use an approximation of equipment he already has?

Quote:
It sounds like all you need to do is keep recording your amp the way you have been, and add a very basic gate plug in (stock in your daw) to your guitar track. Set the threshold above the natural noise level of the amp, and boom-- your noise will be gone.
As will the leading attack and the end of the decay of his notes. I've never encountered a gate that didn't mess with your sound. Now if you happen to want that for an effect that's fine, but it's a distinctive and somewhat limited sound.

If you really MUST get rid of the noise in the recording, edit it out by hand, don't use a robot. Or maybe try strip silence. Editing's better, though.

Quote:
Remember though that a little noise is a good thing sometimes. It's how you know it's real!!
Yes.
Old 30th January 2013
  #5
Here for the gear
 
808 Jake's Avatar
 
🎧 5 years
For a quick fix, gates will work. Play with the attack and release if you feel that you are loosing any attack or decay on your guitar until it's right, or atleast close enough. But as has been said, it probably won't be "perfect."

You've got options, it's however works and sounds best for you.
Old 30th January 2013
  #6
Gear Nut
 
kneelie's Avatar
 
🎧 5 years
You did not mention what kind of cable you are using, If you ever want to try and eliminate hum and if you are using a cheep cable, try a good shielded cable. Braided shielding is most durable. With cables higher capacitance = more high end roll off. Also, make sure the electronics cavity in the guitar is shielded preferably with copper tape.
Old 30th January 2013 | Show parent
  #7
Gear Head
 
🎧 10 years
Quote:
Originally Posted by John Eppstein
Yes, you're missing something fundamental.

You don't need a DI box to plug into your amp, it won't do anything for you.
Right, that makes sense. I think I was just a little blinded by having a DI box in my hands and just wanted to play with it!

Quote:
Originally Posted by 808 Jake
DI your guitar into your DAW of choice if you want to use amp modeling software to minimize hum--- completely cutting out your amp, and any mics you may have.
Thanks for the suggestion man but I prefer a good ole' mic'd up cab. I do use Guitar Rig though for experimentation and sometimes adding to some mic'd tracks for tone although very rarely these days. Mic placement is more fun!

Quote:
Set the threshold above the natural noise level of the amp, and boom-- your noise will be gone.
This however is something I've never played with. My DAW of choice (Ableton) has a gate so maybe I'll give that a go today - thanks for the idea.

Quote:
Originally Posted by kneelie
You did not mention what kind of cable you are using, If you ever want to try and eliminate hum and if you are using a cheep cable, try a good shielded cable. Braided shielding is most durable. With cables higher capacitance = more high end roll off. Also, make sure the electronics cavity in the guitar is shielded preferably with copper tape.
I use 'regular' unbalanced cables. I think I know what you mean though; I have a 15ft one and a 7ft one (better quality too) and when using the longer one the hum is MUCH louder. I guess that's down to the whole unbalanced thing as I read that people advise using the shortest cable possible when using unbalanced? Also, when using that cable to go from my mic pre-amp to the computer, there is no noise/yelling/hum/crying/hiss/screaming. s'good to know that I can use that cable and it's not a waste of money.

Thanks for the replies guys. The whole hum thing doesn't bother me too much; infact I like it! Just wanted to see if an idea worked and now I've learnt a bit more about how DI boxes should be used. I was starting to get a bit obsessed last night though...moving the amp head around my room, plugging the power supply into different plugs and then considered a whole re-design of the room to see if it made a difference. Glad I stopped when I did haha.

Cheers!
Old 31st January 2013 | Show parent
  #8
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
Quote:
Originally Posted by 808 Jake ➑️
For a quick fix, gates will work. Play with the attack and release if you feel that you are loosing any attack or decay on your guitar until it's right, or atleast close enough. But as has been said, it probably won't be "perfect."

You've got options, it's however works and sounds best for you.
Do you want to make recordings that are great or recordings that are "pretty good"?

If all you aspire to is mediocrity the by all means, go ahead and rely on easy shortcuts and develop bad habits.

If you aspire to some day making great recordings don't do that. It's hard enough learning to do things right once without having to unlearn bad habits and lazy attitudes.
Old 31st January 2013 | Show parent
  #9
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
Quote:
Originally Posted by RileyAWA ➑️
I use 'regular' unbalanced cables. I think I know what you mean though; I have a 15ft one and a 7ft one (better quality too) and when using the longer one the hum is MUCH louder. I guess that's down to the whole unbalanced thing as I read that people advise using the shortest cable possible when using unbalanced? Also, when using that cable to go from my mic pre-amp to the computer, there is no noise/yelling/hum/crying/hiss/screaming. s'good to know that I can use that cable and it's not a waste of money.
Always use high quality cable. Some good companies are Belden, Mogami, and Canare. Try to get the spec sheet on the raw cable stock and check the percentage of shielding coverage. Also check the type of shield - spiral wrap shields will slip and lose coverage as the cable gets older. Braid doesn't. Not all braid is created equal though - some cheap cable has a very loose braid, whereas something like Belden 8410 has a very tight braid that gives 80% coverage, which is quite good for guitar cable (some cheap cable is as low as 10%-20%). Cable with a foil shield gives 100% coverage but is unsuitable for guitar cable as it becomes noisy with wear when it gets flexed a lot. (Foil shield cable is typically used for chassis wiring and multicore snakes. Some of the newer cables (I don't know numbers offhand) combine a braid with a conductive plastic layer that can give performance similar to foil but without the drawbacks, but it's costly.

In pre-made cables more expensive is not always better. Some expensive cables look heavy duty but inside are crap.

Oh, and stay away from Monster. Their guitar cables are junk.
Old 6th February 2013
  #10
Lives for gear
 
🎧 10 years
I agree with John, Gates just hide the noise until the music starts... the music will then somewhat mask the noise but still be there... I hate it when that happens...

Move the guitar around, move the mic preamp if possible... use a different guitar but don't think a noise gate is the answer....

I use alot of vintage amps, stomp boxes and guitars and I have all kind of noise... the only remedy I have really found is what I suggested above... it does work.

One of my amps is an old H&H IC100 tranny amp that sometimes plays radio stations all on its own (quietly but it is there)...

Also, to reiterate what John suggested, short cables between effects pedals should be of high quality to minimize noise. Cables that are too long I find also seem to add to the noise...

I hate noise and sometimes you just need to reduce it to a bearable level (including volume) and live with it.

Good luck,
Jim
Old 6th February 2013
  #11
Lives for gear
 
🎧 10 years
To the original poster - as always, more information helps to get better answers.

What kind of guitar - single coil, P90s, humbuckers?
Pedals?
Amp? (if it's an older amp, include the approx year and last time you had it serviced)

Is everything (amp, pedals, etc.) plugged into the same outlet in the room, or different outlets in the room?

If nothing's plugged into the amp, does it still hum?

Otherwise, it's a lot of guessing on what it could be. Thx.
Old 8th February 2013
  #12
Lives for gear
 
Blast9's Avatar
 
🎧 15 years
OP - it sees your amp is humming even with no guitar plugged in?

Is this correct?
Old 8th February 2013
  #13
Gear Head
 
🎧 10 years
Hey dudes, here's some more info

Rocking 2 Ibanez at the mo, a Jem and an RG series. The RG chucks out more hum (MUCH more) which was interesting..haven't played it for a while and didn't actually know this. I just thought I'd try it since you asked...yeah, much more hum with this.

Amp is a Behringer V-Tone Analog Modelling thing which I don't think you can buy any more! Don't judge me on the Behringer, I love it's tone!! haha. That's a head going into some random speakers I got for Xmas when I was a kid, they're super old looking and just say "Intermusic" on the front. That's *all* I know about em..had em for years. Always handled what I threw at it. Two big ole' 15 inchers.

Nothing plugged in - No noise apart from a hiss if I turn it up quite loud..seems to be alright without anything plugged in.

Regarding electronics...it's quite a small room and there's a LOT of stuff plugged in. I have tried unplugging most of my computer/tv/rack and everything but still get the same issue whatevers turned on or off.

If I turn around and move about with the guitar I can make the hum go away but it's always in the most uncomfortable position - typical that!!

I was just messing around earlier and if I move the guitar cable that usually goes into the guitar around my room, the hum gets louder or quieter. For instance, if I put it RIGHT on top of another power supply the hum is huge as you'd imagine. If I put the end right next to where the other side goes into the amp head, the hum goes away.

Need any more info or can you give suggestions based off of that?

Really shocked at how much hum the RG gives out though...I haven't even played it since moving into this new house...
Old 8th February 2013
  #14
Lives for gear
 
Blast9's Avatar
 
🎧 15 years
Quote:
If I turn around and move about with the guitar I can make the hum go away but it's always in the most uncomfortable position - typical that!!
Ah ok - sounds like good old mains hum - you can get that even with humbuckers, especialy if the coils are mis-matched. The only way you can improve it is shielding your pickup cavities, but you're likely to still get some hum.

You might want to check with a different cable - perhaps the screening has broken on your current cable - mind you I'd expect more of a high-pitched noise if that's the case.

FYI there may be something in the next room or upstairs/downstairs that is causing the hum.
Old 8th February 2013
  #15
Gear Head
 
🎧 10 years
I've never considered it coming from another room in the house - thanks for the idea there!

But yeah, as said in older posts, I'm totally cool with the hum even when recording..just an interesting topic y'know?


Thanks again all for your input.
Old 9th February 2013
  #16
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
The source of hum might not even be in the same building. I used to work at a club that had problems with a cyclical, periodic hum coming up in the PA system. We couldn't do a damn thing about it because it was coming from outside the building, which was in a semi-industrial neighborhood with a police station fairly close by. I've always suspected it was some kind of scanning thing, maybe radar, from the police station.
Old 9th February 2013
  #17
Gear Head
 
🎧 10 years
Damn...that sucks, sorry to hear.

You would've thought with today's technology and stuff we'd have conquered something as trivial as hum. It probably goes way deeper than I think though..

When I mentioned I move my guitar around the room and get rid of it, do you think when people (if they *really* don't want the hum at all) move into a room - they set just the amp up first in this empty room and then move around with a guitar, checking for hum? Then once they've found the optimum spot where it's low they move the rest of their stuff around that area? Or if that's a bit too fanatical, do people do something similar? I suppose it's just easier to buy high quality cables and shield your pickups!

There's all sorts of logistical problems that can arise out of that too, just wondered if anyone had heard of someone doing that; the idea came to me this morning. I call it 'hum calibration'
Old 11th February 2013 | Show parent
  #18
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
Quote:
Originally Posted by RileyAWA ➑️
Damn...that sucks, sorry to hear.

You would've thought with today's technology and stuff we'd have conquered something as trivial as hum. It probably goes way deeper than I think though..

When I mentioned I move my guitar around the room and get rid of it, do you think when people (if they *really* don't want the hum at all) move into a room - they set just the amp up first in this empty room and then move around with a guitar, checking for hum? Then once they've found the optimum spot where it's low they move the rest of their stuff around that area? Or if that's a bit too fanatical, do people do something similar? I suppose it's just easier to buy high quality cables and shield your pickups!

There's all sorts of logistical problems that can arise out of that too, just wondered if anyone had heard of someone doing that; the idea came to me this morning. I call it 'hum calibration'
Part of the recording process in real studios is figuring out the optimum place to set up each instrument.

Of course, real studios also are generally designed to minimize sources of electrical noise.

Just out of curiosity, are there any lighting dimmers anywhere in your vicinity?

Shielding pickups is only partially effective. They are, after all, designed to pick up electromagnetic signals.
Old 11th February 2013 | Show parent
  #19
Gear Head
 
🎧 10 years
Quote:
Originally Posted by John Eppstein ➑️
Just out of curiosity, are there any lighting dimmers anywhere in your vicinity?

Nah, no lighting like that anywhere in the house or next door. I only have one house next to me and that's empty at the moment. It's up for sale. Handy when doing late night mastering sessions!

Since learning that the noise could be coming from another room in the house, I noticed the fridge downstairs (about..30..40 feet away?) makes pretty much the EXACT same noise as the hum I get on the amp. I'll try turning the fridge off tomorrow briefly to see if it has any effect. Be good to find out what it is.

Back to you man, do you have any hum problems at your place? Or did you use to? If so, what was doing it and how did you fix it?
Old 11th February 2013 | Show parent
  #20
Gear Guru
 
John Eppstein's Avatar
 
58 Reviews written
🎧 10 years
Quote:
Originally Posted by RileyAWA ➑️
Nah, no lighting like that anywhere in the house or next door. I only have one house next to me and that's empty at the moment. It's up for sale. Handy when doing late night mastering sessions!

Since learning that the noise could be coming from another room in the house, I noticed the fridge downstairs (about..30..40 feet away?) makes pretty much the EXACT same noise as the hum I get on the amp. I'll try turning the fridge off tomorrow briefly to see if it has any effect. Be good to find out what it is.

Back to you man, do you have any hum problems at your place? Or did you use to? If so, what was doing it and how did you fix it?
No worse than normal most of the time. Which is to say that when recording with some of the noisier guitars we have to be careful to stand facing the right direction.
Old 11th November 2019
  #21
Here for the gear
Hi everybody, using the c411 on a small harp that I play, I get a low hum when im plugged into my interface. c411 needs phantom. as some people have mentioned, the hum goes away when I'm holding my instrument and then touching either the metal of computer or the interface. What's the solution to make a ground to get rid of hum? Also, would a DI box solve this issue live and at home? Thanks
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