Something weird

[Bogusrap]

I just finished a strat style with active pick ups. When the switch is in 2 position (bridge and middle pick up) and the 4 position ( middle and neck pick up) the d string and d string only is about 25% of the volume of the rest of the strings. In position 1,3 and 5 everything is normal. Has anyone heard of this and suggest how to fix it? :dontknow:

 

[Cagey]

It's likely the middle pickup is out of phase with the neck and bridge. Swapping the hot/ground leads on that one will probably fix it.

 

[Bogusrap]

Thanks. I will give it a try

 

[kgk9000]

Why is it just one string, the D string?

I'd call the technical support line of your pickup company and see what they think, this is odd.  It doesn't sound like you've flipped the phase, because the other five strings are fine.

What kind of pickups are these, in passing?

 

[Cagey]

Somehow I missed that it was only one string. I wouldn't think it's a phasing problem if that's the case. Or, if it is, the symptoms should invert.

 

[drewfx]

If they are active PU's you can't just swap the leads.

What exactly are the PU's?

 

[Bogusrap]

Why is it just one string, the D string?

I'd call the technical support line of your pickup company and see what they think, this is odd.  It doesn't sound like you've flipped the phase, because the other five strings are fine.

What kind of pickups are these, in passing?

They are Seymour Duncan Live Wire II Classic Strat. I contacted them and am waiting for a solution

 

[Bogusrap]

Just an update. Seymore Duncan was no help. They tried to tell me it was a dead string.
Decided to try some trial and error. Turned the middle pick up 180 degrees. Now the dead string us the G string and the d string is fine. So I have isolated that it is that particular pole on that pick up. I am going to put a new pick up in and see what happens. If it works, it was definitely a faulty seymore Duncan pick up.

 

[mayfly]

wow - that's interesting.  That means that that particular pole piece was installed upside down.  That's a warranty claim IMHO (if you can get them to believe you...)

 

[Verne Bunsen]

That could well be the case if they're using pre-charged magnets. For it to be missed in QC would be quite an oversight!

You might be able to use a magnetic compass to identify if one pole piece is polarized opposite from the rest, although a compass might not see a narrow enough area to reveal it. I use a "Spin Doctor", which is actually a gizmo developed by a slot car guy for their needs, to evaluate the polarity and strength of individual pickup polepieces:

As I was typing this, I recalled that I also have one of the Stew-Mac polarity testers laying around:

Something like that may be more precise than a compass? I don't have any use for it any more since getting the fancy gizmo, so if you don't have a compass or if it doesn't work then PM me your address if you'd like and I'll be happy to send it to you. If it were in fact to verify a defect then it would be difficult for SD to not suck it up and replace it for you. If not, at least you could rule it out... Not to apply pressure but I head out of town for a spell on Tuesday, so if you're interested then the sooner you can let me know the better!

 

[Bogusrap]

Tested the magnetic pole and it was indeed put in upside down at the Seymour Duncan Factory. I Purchased a replacement pick up, switched them out it works fine. Now trying to get a credit for the bad pick up. We will see how that goes.

Thanks everyone for your help.

 

[Cagey]

You would think they'd have some sort of visual indicator dingus on the assembly line to check that sort of thing, since it's not something you can see visually.

 

[AirCap]

Pretty sure most assembly line techniques and practices will apply here. They would only inspect a certain number from every hundred pieces. I can think of no companies who inspect 100% of their products.

 

[Cagey]

Depends what you're making. I've had to design zero-tolerance systems for automotive and military parts suppliers. You don't often get a second chance with things like air bags and missiles, and sometimes there's not a good way to test such things as they destroy themselves if they work  :laughing7:

 

[Bogusrap]

Depends what you're making. I've had to design zero-tolerance systems for automotive and military parts suppliers. You don't often get a second chance with things like air bags and missiles, and sometimes there's not a good way to test such things as they destroy themselves if they work  :laughing7:

I agree. They must have some type of automated testing that checks each pick up, at least for the correct polarity on each magnet.