PRS SE NF3 Issues ???, Grounding, Microphonic Pickups…

[Nathan Shane]

Greetings fellow PRSers. I have some questions and observations regarding my PRS SE NF3:

1. There are 3 individual resistors (one for each pickup) soldered to the 5-way toggle and then to ground. What is their exact purpose? Are they for taming highs, or for each pickup to see the correct resistance? Remember, the Volume Pot is A1M (see wiring diagram).

2. Each pickup seems microphonic, in this respect: I use the 5-way toggle to select a pickup(s), then with the side of my hand (like a karate chop, but NEVER TOUCHING the strings), I can move my hand closer to the selected pickup(s) and grounding noise increases. Pull my hand away, noise decreases? I’ve never experienced this issue with any guitar I’ve ever owned. Ideas? Thoughts anyone?

3. Follow up for question 2. I’m just guessing here, but since those 3 resistors are actually connecting the HOT wire from each pickup to ground, wouldn’t that cause weird grounding issues?

4. When dialing down the Volume Pot:
Full on 10, no issues.
9-grounding noise occurs.
8-Zero, no issues.
I thought I had a bad Volume Pot and replaced it with a new one, exact same issue occurred. Replaced the Volume Pot again with new pot, exact same issue occurs. What is going on? Here’s another wild guess, is it possible for those 3 resistors to be interacting with the resistance of the Volume Pot when the knob is in a specific location (in this case, 9 on the Volume knob). Like the sum total of a specific resistance creates grounding noise?

I’d love to solve this issue…

https://imgur.com/a/NsItawp

https://imgur.com/a/ixMwE6E

 

[shinksma]

I'm no wiring expert, but I'm trying to match all of the wires in your photo (the second one is best) with the schematic provided by PRS, and there appears to be 2 black wires soldered to the Vol Pot casing that are not on their schematic - at the solder point at 3 o'clock on the vol pot in your photo. All of the other connections are accounted for - the three resistors at 6 o'clock, the three pickup ground wires at 12:30 o'clock.

There should be just two, from the schematic: the bridge ground wire and the wire from the tone pot middle lug (also wired through to that third lug on the Vol Pot) at three o'clock. What are the those two wires? Where do they come from/go? Maybe one of them is the other jack plug wire? Does the other go to the pickguard shielding?

If so, then the wiring looks "to spec".

You'll need someone else to open up their NF3 to find out.

It's possible you just have a cold solder somewhere in there too.

 

[Nathan Shane]

Here are two more photos which provide a much wider view of the wiring. After your comments, I rechecked the wiring and it was all good. All the solder joints are nice and shiny and I used a continuity tester to check connections.

The grounding wires soldered to the back of the Volume Pot are:

Three ground wires, one for each pickup.
Ground wire w/ eyelet and screw connected to inside cavity.
Ground wire connected to bridge tremolo spring claw.
Ground wire connected to 1/4” output jack.

https://imgur.com/yyD8ZNv

https://imgur.com/PMD94je

 

[shinksma]

OK, so that answers where the other two ground wires go.

You might just have a bad pickup. Have you measured the resistance or impedance of the pups to see if they are at least in normal range?

Oh, and one more question, which might seem weird: are you using wireless bugs, or direct cable to amp? I discovered that one of my PRS electric guitars (no piezo involved) does not like a certain brand of wireless bugs, and behaves very strangely when moving the volume knob from 10 to 9, like the knob had failed.

 

[Broseph]

Fast way to tell if the resistors are causing an issue is to unsolder them from the switch. See if the issue continues.
They are needed to bring down the total the pickups see. They are above the typical 500k pots associated with humbuckers. But not seeing full 1 meg.

I can’t say I have the issue. I need to de-oxit my switch. It crackles when I change pickups. The volume knob has a fast taper. But I assume that’s typical of Meg pots. I did add a treble bleed to mine

 

[Bobd]

The way I see this, that the things you noted could be the negative side effects of a highly efficient pick up design...

If I interpret the schematic correctly, the resistors connected to the 5 way switch are to lower the output of each pickup.

 

[Nathan Shane]

All right then, it’s Saturday and I found the time to measure the resistance of the PRS SE NF3 Narrow-Field pickups:

NECK: 8.35k
N+M: 4.18k
MIDDLE: 8.29k
M+B: 4.35k
BRIDGE: 9.08k

 

[intothevoid]

Greetings fellow PRSers. I have some questions and observations regarding my PRS SE NF3:

1. There are 3 individual resistors (one for each pickup) soldered to the 5-way toggle and then to ground. What is their exact purpose? Are they for taming highs, or for each pickup to see the correct resistance? Remember, the Volume Pot is A1M (see wiring diagram).

2. Each pickup seems microphonic, in this respect: I use the 5-way toggle to select a pickup(s), then with the side of my hand (like a karate chop, but NEVER TOUCHING the strings), I can move my hand closer to the selected pickup(s) and grounding noise increases. Pull my hand away, noise decreases? I’ve never experienced this issue with any guitar I’ve ever owned. Ideas? Thoughts anyone?

3. Follow up for question 2. I’m just guessing here, but since those 3 resistors are actually connecting the HOT wire from each pickup to ground, wouldn’t that cause weird grounding issues?

4. When dialing down the Volume Pot:
Full on 10, no issues.
9-grounding noise occurs.
8-Zero, no issues.
I thought I had a bad Volume Pot and replaced it with a new one, exact same issue occurred. Replaced the Volume Pot again with new pot, exact same issue occurs. What is going on? Here’s another wild guess, is it possible for those 3 resistors to be interacting with the resistance of the Volume Pot when the knob is in a specific location (in this case, 9 on the Volume knob). Like the sum total of a specific resistance creates grounding noise?

I’d love to solve this issue…

https://imgur.com/a/NsItawp

https://imgur.com/a/ixMwE6E

Did you find a solution? I just picked up a brand new SE NF3 and can report the exact same issue - no noise at 10, but go to 8/9 and noise comes in

It cleans up again below 5 or so. Very annoying issue on an otherwise perfect guitar - also I checked other specimens at the store and they all shared this issue. So it’s not a one off bad pickup or wiring issue. It’s common to them all. There has to be a solution

 

[Nathan Shane]

I never found a solution. I replaced the volume pot hoping that would help, but it didn’t. I’ve seen similar use of resistors (470k/500k) in guitars with an HSS pickup configuration but I don’t own a guitar like that to test with. I can read a wiring diagram without any issues, but I’m no expert when it comes to understanding the technical details of what exactly is occurring electronically. But the fact that the hot signals from each of the SE NF3’s pickups are connected to ground through the use of those resistors just seems technically odd to me. I’m also thinking that when turning the Vol. knob down, we know its resistance is being changed. So perhaps there’s is a sum total of resistance (inline resistors+vol.pot resistance when set around 8/9, that equals noise.

I really like the sound of the SE NF3 pickups but not being able to use the 8/9 position on the Vol. pot is problematic for me, since I often turn down in that area when playing any of my guitars. With the SE NF3, the Vol. remains on 10 at all times.

 

[intothevoid]

That’s really worrying to me

Did you try to contact PRS about it?

 

[Nathan Shane]

No, I didn’t contact PRS. After changing the Vol. pot and with the issue still occurring, I thought why bother. And now that you’ve tried out other specimens with the same exact issue, I’m not sure if it’s a legitimate issue. Kinda like complaining that single-coil pickups produce hum and noise, but that’s just the way it is. Someone else suggested unsoldering the resistors from the backside of the volume pot, I may just do that, I’ll keep ya posted.

 

[intothevoid]

No, I didn’t contact PRS. After changing the Vol. pot and with the issue still occurring, I thought why bother. And now that you’ve tried out other specimens with the same exact issue, I’m not sure if it’s a legitimate issue. Kinda like complaining that single-coil pickups produce hum and noise, but that’s just the way it is. Someone else suggested unsoldering the resistors from the backside of the volume pot, I may just do that, I’ll keep ya posted.

Yes please do keep us posted! Much appreciated