Why ? Telecaster Bridge, No ohm reading, sound like Buchanan

[Mustafa Umut Sarac]

How fail an telecaster bridge pickup , does not give ohm reading and sounds like buchanan ?

Umut
Istanbul

[big_teee]

Welcome!
Check to see that the winding wire didn't get snagged at the eyelets.
Also check that it doesn't have a screw driver gouge, somewhere around the coil.
If you can't find where the wire is broke?
Then it is rewind time.
T

[Mustafa Umut Sarac]

Thank you T for welcoming me,

How earth a coil makes sound when coil wire broke ? Does it have a term ?
How can I find the wire broke location ?

I think sound is not bad , I can rewind a replica for my hyundai telecaster.

Can anyone tell me how does wire broke location effect the sound or does my pickup always have buchanan sound
whereever its broken ?

Umut
Istanbul

[Leo_Gnardo]

How earth a coil makes sound when coil wire broke ? Does it have a term ?

A pickup with broken coil "works" - poorly - thru capacitance. Typical for sound to be thin, and tone control seems to work backwards.

[Mustafa Umut Sarac]

do nancy have a broken wire in the bridge pickup , it works amazing ?

[rjb]

How earth a coil makes sound when coil wire broke ? Does it have a term ?

The term is "capacitive coupling".

Hopefully, a resident expert will chime in with a clearer explanation. But in the meantime:
In a coil, you've got a bunch of parallel wires separated by very thin insulation.
Two pieces of conductive metal (usually plates or foil sheets, but in this case wire), separated by a dielectric (air or insulation) equals a capacitor. The thinner the insulation, the higher the capacitance.
You'll have to ask someone else (or do a web search) to explain the physics....

So, effectively, each turn of wire is connected to nearby turns by tiny capacitors.
If you have a break within the coil, the wire on either side of the break "thinks" it is still connected by a small capacitor.
A capacitor in series with a pickup will pass highs and block lows.
Reportedly, that is why the Buchanan "Nancy" pickup was so thin and trebly.

More discussion here:
http://music-electronics-forum.com/t37918/
http://music-electronics-forum.com/t32819/

How can I find the wire broke location ?

As big_teee said, by visual inspection.
You can try unwinding the coil until you get down to the break, but you'd probably save time by cutting off all the wire with a sharp blade and rewinding with new wire.

But if you LIKE the way it sounds, just leave it alone.

-rb

EDIT:
I knew the cavalry would show up.
Leo posted while I was typing this.

[big_teee]

Keeping it simple, for it to work with the cap coupling, one end of the coil has to be connected.
If both ends of the coil are broke you should get no sound.
With one end connected the signal goes through the coil, then capacitance couples to ground, or vice versa.
T

[rjb]

I think it's a given that the "signal" end of the coil has to be connected.
Maybe the part of the coil "above" the break couples to the part of the coil "below" the break. Maybe it couples directly to ground (possibly via the poles). Maybe both. I dunno. (If anyone knows for sure, please chime in.)
In either case, I think the point is moot. Whether the break is at the coil start or deep within the coil, you still have to rewind the pickup.
Right?

-rb

PS: But if you LIKE the way it sounds, just leave it alone.

[rjb]

Oops.

Re-reading this thread, I just realized that I misread Umut's posts.

He's not wondering how his pickup can read "open" and still produce a sound; he's wondering how Roy Buchanan's pickup could read "open" and still produce a sound.

He doesn't want to fix his own pickup; he wants to wind a replica of Roy B's "Nancy" pickup, and would like to know where to put the break in the coil. I think.

Before investing the time and money to build an intentionally broken pickup, I would take a hint from the post below, and try this:
Solder a 3300 pF ceramic capacitor in line with one of the leads from the bridge pickup in your hyundai telecaster.
http://music-electronics-forum.com/t32819/#post299818

If that doesn't sound like "Nancy", I bet it'll be pretty close.
Then take two aspirin (for the "icepick in the ear" headache) and call in the morning.

-rb (Definitely not Roy Buchanan)


PS:
FYI, Ceramic caps cost a penny a piece at Tayda (based in Thailand & USA, worldwide shipping).
Save time Easy Ordering Page for Ceramic Disc Capacitors - Ceramic Disc Capacitors - Capacitors

[big_teee]

Beats my two Pair!
I try not to make broke pickups!
To sound like him, you probably need to be Roy Buchanan!
T

[rjb]

To sound like him, you probably need to be Roy Buchanan!

Yes, there is that.

---

And now for a musical interlude. (Sorry, I just can't help myself.)

[Mick Bailey]

Without taking the original pickup apart there's no way to determine how it it 'broken'. Neither do we know what spec of meter was used to take the resistance reading. Is it open, or has it been measured with a meter that (say) reads open at 10M Ohm? It could have a high resistance, but not be truly open-circuit. This sometimes occurs with a corrosion spot that's eaten through the wire but left a resistive metallic compound. The capacitive coupling is limited by winding layer proximity and could only be in the order of low pf, in my opinion.

So, maybe a better way to emulate the pickup would be to have a high value resistor in parallel with a small value capacitor.

Edit; I see a difference between the distributed capacitance in the pickup and the effective capacitance that could couple a signal. I think of the capacitive coupling being more like a 'gimmick' cap that would be something like 1pf per inch, though that would be for a twisted wire. Maybe there's some inductive coupling in the pickup, too

[rjb]

So, maybe a better way to emulate the pickup would be to have a high value resistor in parallel with a small value capacitor.

...Maybe there's some inductive coupling in the pickup, too

Maybe a resistor/capacitor network would more closely model a corroded spot.
Maybe a more complex model would be even closer.
Maybe we're over-thinking this.
With all the other factors involved, I can't see how one could know he had "nailed" the "Nancy" tone.
Or why he would want to.*

FWIW, madzub sez he got Nancy tone from a 7K coil tapped at 5K...
http://music-electronics-forum.com/t32819/#post299810

This was kinda fun, but I'm done now.

-rb


* I'm not the only person who feels that while Roy's playing was phenomenal, his tone was not.

[Justin Thomas]

Maybe if we keep adding resistors, caps, and inductors in random combinations and then wind the whole mess on a bobbin instead, we'll clone the sounds of ALL our favorite pickups, and won't have to fool with all that skinny-ass bitch wire that breaks all the time in impossible to find places...

(Ducks behind couch)

Justin

[big_teee]

An experiment we could try?
Take a regular Tele bridge pickup with a metal bass plate.
Take the black lead & strap to baseplate, off of the start lead eyelet.
Re-terminate the black lead directly to the baseplate.
Then test the pickup.
Not sure what it will sound like.
That allows the output to flow through the coil without a ground termination.
If I get time I will try it tomorrow.
T