Passive Pickup Hum

Joined: 09 Nov 2005 Posts: 818 Location: Canada

Hey, first off I'm pretty sure I know the answer to this. I just thought I would post to give you guys a good laugh.

I got my first passive pickup in the mail today. A Seymour Duncan Distortion to go into my Edwards Alexi guitar. So I am VERY new to passives and how they work. I have installed many EMGs and Blackouts.

So I had everything on the guitar apart for basic cleaning and what not. I had the bridge removed and left it off while installing the pickup.

After wiring everything I thought I would plug it in and test it out by giving the pickup a tap to make sure it was picking up sound. Right away I noticed mad humming. I started freaking out and trying to figure out what I wired wrong.

Well like I said, I am new to Passives and totally didn't think about the grounding. Without the bridge on and the strings going across the neck my hands were not in contact with the ground loop at all causing mad buzz. I have never had this issue before because active pickups don't require the same kind of grounding that passives do. This is how I have tested all my active pickups, before throwing the strings back on. It was just very funny how I never thought about it and started panicking.

Well, thats my boring story. I hope you didn't waste your time reading this far Razz

I assume this passive is going to buzz and hum a bit more than my active EMGs do, right? Or maybe there is a problem with my install job?

Now, I am being all paranoid about my "not so professional" soldering job affecting the sound. How likely is it that a poor solder job will affect the sound? There are no cold joints or anything. I practically picked the guitar up by each wire I soldered to test the strength. Just new to passives and am overly worried.

What about shielding? Should I add some extra shielding in the cavity? There only seems to be shielding on the plastic cover.

Joined: 28 Sep 2012 Posts: 379 Location: Kent, UK

Sounds to me like a grounding issue.

I'd shield all of the cavities with copper anyway as well.

Joined: 23 Nov 2005 Posts: 8257 Location: Ontario, Canada

You don't really need shielding in a cavity if your wires are shielded. My TCML had no shielding in the cavity and the wire. Uncles had no shielding either. It buzzed bad. I changed out the tiny wire bundles for vintage braided wire and it's ninja quie now. Can you post pics of the cavities?

Joined: 27 Feb 2006 Posts: 13396 Location: Earth

If it's properly installed there should be no humming or buzzing. Passive humbuckers are very quiet. They "buck" the hum Laughing

Most guitars I have had with actives have always been noisier than passives.

Joined: 23 Nov 2005 Posts: 8257 Location: Ontario, Canada

Lanning is Killdozer wrote:

If it's properly installed there should be no humming or buzzing. Passive humbuckers are very quiet. They "buck" the hum Laughing

Most guitars I have had with actives have always been noisier than passives.

That's true but if you have unsheilded wire like my TCML and USA DFH had than you have humbuckers that buck the hum but wire that acts as an antanna to attract the hum and pass it through to the amp.

Joined: 09 Nov 2005 Posts: 818 Location: Canada

Hey guys here are the pics

I am definitely not the happiest with the top ground solders. I find it a little harder to solder to a flat surface and had troubles getting the solder to stay in one spot and not spread out so much.

The install was following this diagram and everything was checked over with a multimeter for continuity: http://cdn.seymourduncan.com/pdfs/support/schematics/1hum_1vol.pdf

If I was to resolder it, I think I would get a new pot and soldering iron (or maybe just a new tip).

Joined: 07 Aug 2007 Posts: 2740 Location: Southeast MI

Probably a ground loop in there. We'd have to see a schematic or details of what's going where for the whole guitar. That's my guess anyways.

Posted: Tue Nov 27, 2012 9:03 pm

Lanning is Killdozer wrote:

If it's properly installed there should be no humming or buzzing. Passive humbuckers are very quiet. They "buck" the hum Laughing

Most guitars I have had with actives have always been noisier than passives.

I agree, my old Razorback V had EMGs, and they were noisy as hell. Im probably gonna stay passive from now on. Cool

Joined: 09 Nov 2005 Posts: 818 Location: Canada

GuitarGoat wrote:

Probably a ground loop in there. We'd have to see a schematic or details of what's going where for the whole guitar. That's my guess anyways.

I'm not sure what you mean. That is the schematics for the whole guitar. The only thing missing is where the ground wire is going to. It is soldered to the back of the tremolo claw (factory solder). This guitar only has one pickup and one volume knob.

I also replaced the B500K pot with a brand new one I had. The original pot was scratchy and not smooth to turn. So everything was replaced but the output jack, output jack wire, and original ground wire.

By the way,
I am getting some work done on the guitar regarding the frets. Since I have it at a tech, I will also get hgim to check out the wiring job I did.

Joined: 07 Aug 2007 Posts: 2740 Location: Southeast MI

What's the second black wire coming in with the pickup wiring?

Joined: 19 Jan 2007 Posts: 3201 Location: UK

If you re solder that get some stuff called solder wick (desolder braid) it's like the woven wire that covers some cable and what it does is mops up all the old solder and you can make a pot look brand new again.

Also check what wattage your solder iron is, i think the reason why it spreads out like that is mainly because the solder itself is pretty weak at heating area fast enough so the heat spreads out over time and when it gets up to temperature to stick the whole back plate is hot.

hope that helps you a bit

Joined: 09 Nov 2005 Posts: 818 Location: Canada

kingoflight wrote:

If you re solder that get some stuff called solder wick (desolder braid) it's like the woven wire that covers some cable and what it does is mops up all the old solder and you can make a pot look brand new again.

Also check what wattage your solder iron is, i think the reason why it spreads out like that is mainly because the solder itself is pretty weak at heating area fast enough so the heat spreads out over time and when it gets up to temperature to stick the whole back plate is hot.

hope that helps you a bit

Yeah I have used solder wick before. I also have a desolder pump which also works pretty good. The wick is definitely nicer but the pump does a pretty decent job as well. That pot had close to zero solder on it when I started the install.

I think you are right about the iron. I was feeling the same way during the install. I had to hold it for a fair bit of time before the solder would even start to flow. I think its a 30W iron. It's a pretty small tip and I mainly use it for circuit board work and very small solder points.

GuitarGoat wrote:

What's the second black wire coming in with the pickup wiring?

The second black wire is the output jack wire.

Joined: 07 Aug 2007 Posts: 2740 Location: Southeast MI

Is the wire labelled "output jack" shielded and if yes is the shield attached to both the back of the pot and the jack?

Joined: 09 Nov 2005 Posts: 818 Location: Canada

Hey, I don't recall seeing any shielding on the output jack wire.

Joined: 25 Dec 2004 Posts: 1949 Location: NY

From looking at that; I'd say there's a good chance you melted that pot and that is where your noise is coming from.

A sure way to find out would be to wire the pickup right to the output jack. If there's no more buzz, then it's the pot.

Joined: 07 Aug 2007 Posts: 2740 Location: Southeast MI

dan_plus_o wrote:

Hey, I don't recall seeing any shielding on the output jack wire.

I misunderstood I think where these wires are going...so you have three connections on the back of the pot, one for the ground for the pickup, one ground to the bridge, and the "output jack" wire uses the shield to the sleeve of the output jack...am I correct?

Joined: 09 Nov 2005 Posts: 818 Location: Canada

Powerglide350 wrote:

From looking at that; I'd say there's a good chance you melted that pot and that is where your noise is coming from.

Yeah I think your probably right. As I was saying above, my iron didn't seem to heat up the pot right away. I had to hold it there for a bit before the solder would even start to flow and by then it was flowing everywhere. This is a cheap $20 iron I have used for over 5 years. I think I should invest in a new quality one.

GuitarGoat wrote:

dan_plus_o wrote:

Hey, I don't recall seeing any shielding on the output jack wire.

I misunderstood I think where these wires are going...so you have three connections on the back of the pot, one for the ground for the pickup, one ground to the bridge, and the "output jack" wire uses the shield to the sleeve of the output jack...am I correct?

Yeah that's correct. I couldn't remember if there were two wires for the output or one wire with shielding. Now that I think of it, I think it was just one wire with shielding. There are three ground connections going to the back of the pot. Bridge, Pickup, and Output. Shielding that is soldered to the sleeve ring of the output jack is soldered to the top of the pot.

I have a local technician doing some fret work on the guitar right now. I asked him to check out the wiring and he said the output was very low. He said replacing the volume pot solved the issue. So I must of heated that pot up a bit too much.

Joined: 07 Aug 2007 Posts: 2740 Location: Southeast MI

dan_plus_o wrote:

Powerglide350 wrote:

From looking at that; I'd say there's a good chance you melted that pot and that is where your noise is coming from.

Yeah I think your probably right. As I was saying above, my iron didn't seem to heat up the pot right away. I had to hold it there for a bit before the solder would even start to flow and by then it was flowing everywhere. This is a cheap $20 iron I have used for over 5 years. I think I should invest in a new quality one.

GuitarGoat wrote:

dan_plus_o wrote:

Hey, I don't recall seeing any shielding on the output jack wire.

I misunderstood I think where these wires are going...so you have three connections on the back of the pot, one for the ground for the pickup, one ground to the bridge, and the "output jack" wire uses the shield to the sleeve of the output jack...am I correct?

Yeah that's correct. I couldn't remember if there were two wires for the output or one wire with shielding. Now that I think of it, I think it was just one wire with shielding. There are three ground connections going to the back of the pot. Bridge, Pickup, and Output. Shielding that is soldered to the sleeve ring of the output jack is soldered to the top of the pot.

I have a local technician doing some fret work on the guitar right now. I asked him to check out the wiring and he said the output was very low. He said replacing the volume pot solved the issue. So I must of heated that pot up a bit too much.

There you go! You're back in business. I was going to say...the wiring looks correct. Good luck.

Joined: 09 Nov 2005 Posts: 818 Location: Canada

Thanks for the help guys.

Now I am just waiting for my tech to order the correct size of fret wire. Soon I will be shredding on the Edwards Very Happy

Posted: Fri Nov 30, 2012 12:52 am

If you ever have a Guitar that is not quiet unless you are touching the strings..........you have a grounding problem. I usually shield
my Guitars. It is crazy but the Import Denas typically have shielding
paint in the cavities.................the USA's don't and every USA I have
had......hums in my music room. I have flood lights in there, not Flourecents. A good Shielding job and making sure everything is properly grounded, usually makes them silent. I have had a couple
of pups that just hum'd no matter what, those usually get pulled.