ground lifting

[perelectric]

Hi,

Does anyone out there know if it's at all possible to lift the ground in Fender's noiseless strat pickups? I'm thinking of making it possible to connect them out'ofäphase and in series, and noticed that in these setups, sometimes the groudning of the poles etc would be connected to the hot side. I'm thinking the only possible solution to avoid getting all kinds of hum is to lift the ground and ground it with a separate wire. Trouble is, I don't know if it's possible. Is it, and how do one go about it?

Thanks,
Per

[sumgai]

Per,

I take it that you're speaking of Fender's SCN pickups, right? In that case, you must leave the green wires connected to ground - they are the internal shields of the pickups. You can safely play with the black wires as you wish in order to make series or OoP connections with other pickups.

If your pickups have only two wires to begin with, then you aren't looking at true Fender noisless pickups. In such cases, you can play with the circuitry, but you might end up with some noisy combinations. Shielding will help, if you haven't already done so.

In my experience, Fender has never physically connected a wire to a magnet pole in a single coil pickup, so don't worry about that aspect of things. (Note: This may not be true for any humbuckers used by Fender, I've never had reason to check 'em.)


sumgai

[perelectric]

Hi sumgai,

Thank you for your reply.

Actually, no, I'm not speaking of the SCN pickups, I'm talking about the older version of Fender's noiseless with just two wires. I haven't bought the pickups yet, so I can still change my mind. Would I be better off with a pair of SCNs?

Hmm, I've always thought that the magnet poles were grounded... My mistake. How about the attachment screws?

I haven't shielded it yet, but it will be the first thing I do.

Thanks,
Per

[sumgai]

Per,

I was unaware that anybody, let alone Fender, had made any pickups with only two wires that they could call truly noisless - that would be the Holy Grail! Even Kinman needs three wires, and he's about the most advanced pickup winder in the biz.

That said, you're certainly welcome to try using the two-wire pickups, and placing what would be the ground in other wiring modes, but I don't hold out a lot of hope that the pickups will be somewhat noise free. It's just the nature of the beast, that's all.

While a young sprite, I did this exact thing to many, many guitars, both for myself and for others, over a period of maybe 4 decades. In every case I can recall, if the ax wasn't already shielded, then installing a full shield system cut the noise by better than 90%, which in most cases is quite tolerable. Still, the new three-wire pickups with shielding are a lot better than that, so if yoiu're heading for a studio anytime soon, I would advise you to carefully consider your choices. ;D

I was intending to drop you line again anyway, about another topic in your original message. Here goes....

I did some more thinking about what you said about the magnets. I couldn't remember what the effect was, so I opened up one of my own axes last night, and did a bit of experimenting. If you have a pickup that is "hanging" on the hot side (not connected to ground), they it is possible that the magets of that pickup will emphasize the hum as your fingers come near them. The solution is obvious - don't leave any coils dangling out in the wind. Sometimes that's just not possible in order to get the wiring you want, but so long as you're aware of possible consequences, that's OK.

And to top it all off.... A pickup's attachment screws are going through plastic. If there is a shield on the underside of that pickguard, then the threads of the screw might make contact, and be grounded - but they could just as easily not be touching, too. The threads in the pickup itself (or its cover) are usually not grounded, but I suppose it could be done. Seems like overkill to me, but hey, what do I know?

HTH!

The longwinded one,


sumgai

[perelectric]

Hmm, so a pickup has to have three leads to be truely noiseless. Thanks!

I modded my tele (MIM) a few years ago. Shielded it with conductive paint (very handy), changed the pickup switch to Fender's four-way and the pickups to Fender vintage noiseless tele pickups. They sound really, really good compared to the stock pickups. These only have two leads, one hot and one ground.
However, when you mentioned that a truely noiseless pickup would have to have three wires I realized that my pickups actually are stacked humbuckers. Do you know if the SCN's only have one coil?

So the screws won't be a problem then, thanks for letting me know. I haven't done so many mods, so I don't really know what matters and what doesn't. All I know is that it took me two weeks of head scratching before I got my tele noiseless.

Thanks for your help, it's really appreciated!!
Per

[ChrisK]

Fender Strat SCN's have two coils (which makes them humbucking) and those PU's in my Fender Am Dlx S-1 SSS Strat only have two wires. The coils are in series out of phase, but the poles are North all of the way through (top and bottom). The actual magnets are between the coils a la' a stacked P-90. Look in the Fender catalog or on their web site to see the construction.

My Fender Tele Vintage Noiseless bridge PU only had two wires (it now has four since I converted it to four wire). The pole pieces (magnets) are one polarity on the top and the other on the bottom. The coils are out of phase to each other (humbucking). The differential mode signal from the coils ?subtracts in this design.

There are green wires in Lace PU's. Lace PU's have been sold in Fender guitars.

A perfectly wound humbucker only needs two wires. Most are imperfectly wound (dual resonance) to effect "tuning" and can make use of a shield.

A PU does not have to have a shield to be humbucking, but even a shield won't make any physical device perfectly "noiseless" (as in NO common mode noise).

Many side by side coil humbuckers have their frame connected to the shield wire and are thus as "grounded" as the shield is.

Many humbuckers have shield wires, some do not. Some single coil PU's have shield wires, many other's do not. Some PU's have their case connected to one of the wires (Tele covered neck).

There are no real constants in this area.

[sumgai]

Per,

Thanks for your help, it's really appreciated!!

You're most welcome. And don't worry about how long a project takes. No one said that this stuff is easy the first time around. None of us were born knowing all there is to know about electronics, modding, tone, etc. Stick around, listen, ask questions, work on junkers (or your friend's guitars :, and pretty soon, you'll be making your own contributions here! ;D

Chris said that "There are no real constants in this area." I pretty much agree with him on that. I have more to say on this topic, but I should speak directly with Chris, just to be courteous.

Stay tuned!


sumgai

[sumgai]

Chris,

I, too, have a 2005 AmDlxSSS w/S1, but my pickups came with three wires each, not just two. That is, unless you're referring to 'two signal wires, plus one ground'.

I think you'll agree that guitar makers vary their products from year to year, sometimes almost violently. It's a wonder we can keep even partial track, ain't it?

There are green wires in Lace PU's. Lace PU's have been sold in Fender guitars.

Yes, that's true. But my particular pickups aren't Lace - they'd be labeled so, if they were. From that, I deduce that either Fender has sub-contracted from another supplier, with the proviso that they be branded as Fender, or else they are making these pickups themselves. And with a green third wire.

A perfectly wound humbucker only needs two wires. Most are imperfectly wound (dual resonance) to effect "tuning" and can make use of a shield.

Define perfect. Do you mean in terms of the physical properties of the windings, their electrical characteristics, their tone, what? Even then, the two wires would still only represent only one possible combination of connecting the two coils. I contend that no matter how 'perfect' any two coils are, there are going to be tonal differences in the various methods of connecting them together, which in turn may be attractive to a player/modder.

Everything else you said I fully agree with. But you said it shorter and sweeter. Sigh. Some day I'll learn to be terse instead of verbose, I swear I will!


sumgai