# Help me lose a hum in my Bodhran



## Guest (Jan 1, 2007)

Not sure if this is in the right place, but it can't hurt right.....

O.k.... here's the pic.... 









A is the Mic
B is the battery pack to power the mic
C is the MONO 1/8th plug
D&E.... A 1/4-1/8 endpin 'jack' from Shadow
F.... a 1/4 guitar chord.... 

I plug it all in and it BUZZES like mad.... BUT if I touch (ground) D, E & F it works jim-jam-dandy.... any suggestions how to ditch the humming in a more perminent way?

Thanks!


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## PaulS (Feb 27, 2006)

There is nothing to ground to it is all wood. That is why when you touch it you become the ground path and it quiets down. I seen this item someplace, it was like a ring with a small cable that attached to the grounding point. You wear the ring on the hand that holds it and you have your ground. Not sure but it could work...


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## Guest (Jan 1, 2007)

Then how come when the endpin jack is in a guitar, hooked up to a Shadow soundhole pickup, it doesn't hum? My guitar is all wood too.... 

??? 

:confused-smiley-010


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## Wild Bill (May 3, 2006)

*"Make with the sireen, Blab!"*

Assuming that there's no broken cord/connection stuff going on my first test would be to try another amp!

Essentially there's no difference in having a pickup inside your bodhran than in one being in your guitar, or holding a microphone.

It sounds like the amp doesn't have a true ground or a poor or non-existing ground in the house wiring.

Does a guitar or microphone plugged in to the same input hum the same?

Have you tried a different amp?

Hum that disappears when you touch the strings of your guitar or in your case the outer shell of a plug in your bodhran means that your body is acting like a big sink to ground because there isn't a good path through the amp.

Give us more info!

Or, as Johnny Five said in the movie "Short Circuit", "MORE INPUT!"


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## washburned (Oct 13, 2006)

Wild Bill said:


> Essentially there's no difference in having a pickup inside your bodhran than in one being in your guitar, or holding a microphone.
> 
> 
> So is the mic acting like a single coil pickup, i.e when you grab the strings the hum is reduced, but when you let go the hum comes back?


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## Ripper (Jul 1, 2006)

I seen this used before too for similar circustances with amplified acoustic guitars. Take your cable that goes from the Bodhran to the amp. Pick one end and make sure you mark it somehow. This is the end that goes to your Bodhran. Cut the ground wire connection at this end. The ground wire on the amp cable then becomes ground-relative to the amp. I'll bet it's the battery pack that is causing the issue. Doesn't take long to try it and you can always put it back to normal quickly. It may not work, but it might just be the ticket too.


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## Wild Bill (May 3, 2006)

*"I dunno...*



Ripper said:


> I seen this used before too for similar circustances with amplified acoustic guitars. Take your cable that goes from the Bodhran to the amp. Pick one end and make sure you mark it somehow. This is the end that goes to your Bodhran. Cut the ground wire connection at this end. The ground wire on the amp cable then becomes ground-relative to the amp. I'll bet it's the battery pack that is causing the issue. Doesn't take long to try it and you can always put it back to normal quickly. It may not work, but it might just be the ticket too.


If you do this, where is the signal return path for the pickup? It sounds to me like you're describing having only one wire as a connection to the pickup, unless I misunderstood. You can do this with shielded wires inside an amp or with connections to a reverb tank but that's because the ground signal return is through the power supply. With the Bodhran it sounds like hanging a light bulb up by only one wire and trying to light it is the equivalent of your model. Then again, I just got up and my brain may be too fuzzy to understand what you said.

The previous post asked "So is the mic acting like a single coil pickup, i.e when you grab the strings the hum is reduced, but when you let go the hum comes back?"

The short answer is YES! Of course, there's an extra kicker. Any metal surface like a chassis, the shield on the outside of a connecting cable or the strings on a guitar (which are normally grounded through the output jack and cable back to the amp) acts like an antenna to pick up the AC hum in the air which comes from all the AC wiring in our world.

Making sure the unit has a good low-impedance ("resistance") path to ground through the power cord and house wiring dramatically reduces the hum. If the home wiring has a ground problem then the induced hum currents are not drained on the outside by an easy path and instead find other paths more to their liking, like through a gain stage inside the amp!

http://www.guitarnuts.com has some good FAQs about this. Think of the bodhran as like a guitar and the info applies in the same fashion.

http://www.aikenamps.com has some great FAQs to do with grounding methods inside amplifiers, if you want to dig a little deeper. More than you need for this problem but invaluable if you sniff the solder inside amps.


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## Ripper (Jul 1, 2006)

Duh...Wild Bill is correct on what he said, I shouldn't post after having a few wobbley pops at practice. What I wrote down is great if you have a shielded cable and are having problems, won't work with a straight guitar cable.


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## Ripper (Jul 1, 2006)

Is that a Sony ECM-T115 lapel mic you're using? If it is, this isn't quite the same thing as an acoustic guitar pickup. Those Sony mics are designed for use with a digital recording device for use with meetings etc. We have them at work. They can be powered either by your battery pack, or through their cable with certain Sony recorders and then from there into a broadcast system.


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## Guest (Jan 2, 2007)

"Is that a Sony ECM-T115 lapel mic you're using?"
There... a question I CAN answer... actually it's a Sony ECM-C115... is that a problem?

Is there a solution??


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## Wild Bill (May 3, 2006)

*"Input! More input!"*



ClintonHammond said:


> "Is that a Sony ECM-T115 lapel mic you're using?"
> There... a question I CAN answer... actually it's a Sony ECM-C115... is that a problem?
> 
> Is there a solution??


CH, it shouldn't make any difference. There are red mikes and blue mikes but they all send volts over wires just the same.

Have you tried a different amp? Have you plugged it in to another outlet in a different room or better yet a different house?

We have to nail a few things down or we'll just keep shooting in the dark...


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## Ripper (Jul 1, 2006)

ClintonHammond said:


> "Is that a Sony ECM-T115 lapel mic you're using?"
> There... a question I CAN answer... actually it's a Sony ECM-C115... is that a problem?
> QUOTE]
> 
> ...


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## Guest (Jan 3, 2007)

" Have you tried a different amp?"
Yes... same thing.... 


"Have you plugged it in to another outlet in a different room"
Yes... same thing... 


" or better yet a different house?"
Yes... same thing... 

does that help??


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## Wild Bill (May 3, 2006)

*"circling in on it..."*



ClintonHammond said:


> " Have you tried a different amp?"
> Yes... same thing....
> 
> 
> ...


A bunch!

Now let me think about it for a while...


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## Guest (Jan 4, 2007)

Bartender... get WB here a pint while he's thinking

;-)


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## Wild Bill (May 3, 2006)

*"Un autre Molson, s'il te plais..."*



ClintonHammond said:


> Bartender... get WB here a pint while he's thinking
> 
> ;-)


Well, I was hoping you wouldn't give us those answers! We now moved out of "easy to fix" territory and more into the PITA badlands...

I see only 2 possibilities. First, try another mike. It may be that the wiring of this one has a problem. Oftentimes the small cords on these mikes break their shields at the connector ends. Mikes with metal cases are supposed to have the case grounded to the shield on the cord. Sometimes this is either broken or even forgotten when assembled at the factory. If you have a meter you can check if the metal case is grounded to the shell of the connector plug.

Second, unbunch the cords! You've got the excess cordage bunched up and taped to the cross struts of the drum. Those cross struts also look like metal, which would make what I'm thinking even worse.

You see, a coil of wire makes a much better antenna than a straight length. And longer lengths pick up more stuff than short lengths. The outside shield of a mike cable can act like an antenna wire by itself. Bunching makes it into a GREAT hum pickup coil! 

Untape the bunched up wires and just let them hang. Listen to hear if the hum gets better or worse. If it gets significantly better then the solution is to hack the mike wiring to have the shortest possible non-bunched cord.

Try it and let us know...


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## Guest (Jan 4, 2007)

"more into the PITA badlands..."
Tell me about it... I've been chasing after a decent solution to Mic this drum for almost a year....


When plugged into the MD recorder, the Mic hums not in the least.... So it's no the wiring in either of the Mic units.... 

The cross pieces on the drum are wood.... 

Undoing the "coils" affects the hum not at all, for tge good or worse....

"taped to the cross struts"
Velcro chord-wraps as a matter of fact.... 

And for the record, I "coil" all my excess guitar cabling and velcro tie-wrap it... have done for years and years and have never had a problem.... 

I HATE having a mess of chords on the floor where I'm trying to work....


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## jimmy peters (Nov 29, 2006)

*grounding issues*

have you tried grounding the pups to the strings ?
very elementry , but?
good luck
jimmy peters


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## Ripper (Jul 1, 2006)

OKay, I brought one of those little babies home from work. Clint, I get the same problem you have not matter what amp I plug into etc. I tried it by itself, on my Bodhran, still hums. I plugged into my Mackie mixer and the hum goes away. Interestingly though, when I plug into a cheap behringer acoustic pedal that I have here, the hum disappears and the mic works flawlessly with any of the amps. Have you thought about going into a pedal like this then into the amp? I was goofing around with it and my Bodhran and you can really sweeten the sound with it. My luthier buddy said he has come across the same thing with some of the single mic systems he has used.

These mics are intended for use into digital recording equipment and then into a amp system of some type. I would bet it has something to do with the power system for the mic causing a ground issue when straight into the guitar amp.


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## Guest (Jan 5, 2007)

"Have you thought about going into a pedal like this then into the amp?"

I'd run it into an A/B switch in a perfect world, so that both my guitars (Identical A Series Seagulls) and my bodhran only need one channel.... (I can only play one at a time anyway)

Tell me more about this peddle that you have...

"have you tried grounding the pups to the strings ?"
I have no idea what yer even asking me....


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## Ripper (Jul 1, 2006)

It's a Behringer ADI21 V-tone acoustic pedal. It belongs to a friend of mine. He plugs his violin, mando etc into it when he comes over to jam from time to time. They aren't a very expensive pedal, here's the info from the Behringer site http://www.behringer.com/ADI21/index.cfm?lang=ENG
I don't do alot of amplified acoustic stuff myself, but I sure like the sound you can get out of this little pedal.


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## Wild Bill (May 3, 2006)

*Aha! Ahahaha!*



Ripper said:


> OKay, I brought one of those little babies home from work. Clint, I get the same problem you have not matter what amp I plug into etc. I tried it by itself, on my Bodhran, still hums. I plugged into my Mackie mixer and the hum goes away. Interestingly though, when I plug into a cheap behringer acoustic pedal that I have here, the hum disappears and the mic works flawlessly with any of the amps. Have you thought about going into a pedal like this then into the amp? I was goofing around with it and my Bodhran and you can really sweeten the sound with it. My luthier buddy said he has come across the same thing with some of the single mic systems he has used.
> 
> These mics are intended for use into digital recording equipment and then into a amp system of some type. I would bet it has something to do with the power system for the mic causing a ground issue when straight into the guitar amp.


I'll bet 3 beer you're absolutely right! Odds are an ordinary mike that needs no power supply would work fine, if its either high impedance or has a matching transformer to kick it up to match a high impedance guitar amp input.

Anyhow, keep track of the beer! Who knows when we'll have a chance to square up? It's a small world!


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## Wild Bill (May 3, 2006)

*"The same, only different!"*



ClintonHammond said:


> "more into the PITA badlands..."
> Tell me about it... I've been chasing after a decent solution to Mic this drum for almost a year....
> 
> 
> When plugged into the MD recorder, the Mic hums not in the least.... So it's no the wiring in either of the Mic units....


See Ripper's post!



ClintonHammond said:


> And for the record, I "coil" all my excess guitar cabling and velcro tie-wrap it... have done for years and years and have never had a problem....
> 
> I HATE having a mess of chords on the floor where I'm trying to work....


You're right! You never should have a problem!

If the ground's ok, of course.  If uncoiling the wire had changed the hum we would have instantly confirmed there was something fishy with the ground wiring of the mike.

If you know a good tech locally he might be able to open up the internal wiring of the mike and re-arrange the grounding scheme to eliminate the hum. Never having worked with your model of mike and not being able to see inside the unit means I'd have to be psychic to come up with the specific solution.

Now, if you could coax Ripper with some beer to open up the unit he has... :banana:


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## Guest (Jan 5, 2007)

"I'd have to be psychic"
You mean you're not?!?! Well fat lotta good THAT does me!!

LOL

thanks for the attempts guys... I'll yack around with some tech-guys locally and see if one of them can help with more hands on... 

Be well


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## Ripper (Jul 1, 2006)

Okay I disassembled this little fellar I have here (I can't stop myself from taking things apart). These definitely weren't designed for a performance type of useage. Coupled with the way they have it set up to take power from the input cable (most powered mics use a balanced connection), I'm really not sure there is a whole lot you can do to fix the situation short of using a pedal of some type.


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