Are they Gibson Classic '57?

[LtKojak]

Hi guys,

I think I need a hand here... so's the deal:

I've bought a second hand set of Gibson Classic '57. I've took'em out myself from a Gibson guitar. They measure 8.68k and 8.99k.

Today I've got another set of Gibson Classic '57 to put in a 335 copy and, measuring'em, I've found out they measure 8.22k and 8.54k.

Do you think Gibson changed their specs overtime or one of the sets' not a Gibson?

I can't find the real specs on the net... can any of you help?

Yours very truly,

Pepe aka Lt. Kojak
Milano, Italy

[Sweetfinger]

Mine (still new in display boxes) measured 8.2 K which is surprisingly a bit higher than I would have thought. You might have the '57 Classic Plus, or Burstbuckers. They all look the same. Anybody else?

[RedHouse]

As far as Burstbuckers, I have a I, II, and III here on my bench. The I and II are out of my 04 R9, the III was not.

I= 7.9k
II= 8.38k
III= 8.95k

One of your's might be a BB-III, a classic plus can be id'd by a smooth A5 magnet IIRC, these BB's have the "sand cast" rough A2 magnets.


{EDIT}
additional info for those interested:

Slug coil is dominant on each of them

I= 7.9k........SCR = 3.92k - SLG = 3.98k
II= 8.38k.....SCR = 4.16k - SLG = 4.22k
III= 8.95k....SCR = 4.41k - SLG = 4.54k

SCR: screw coil
SLG: slug coil

[LtKojak]

As far as Burstbuckers, I have a I, II, and III here on my bench. The I and II are out of my 04 R9, the III was not.

I= 7.9k
II= 8.38k
III= 8.95k

One of your's might be a BB-III, a classic plus can be id'd by a smooth A5 magnet IIRC, these BB's have the "sand cast" rough A2 magnets.


{EDIT}
additional info for those interested:

Slug coil is dominant on each of them

I= 7.9k........SCR = 3.92k - SLG = 3.98k
II= 8.38k.....SCR = 4.16k - SLG = 4.22k
III= 8.95k....SCR = 4.41k - SLG = 4.54k

SCR: screw coil
SLG: slug coil

Thank you very much, RedHouse! Very interesting info indeed!

Yours truly,

Pepe aka Lt. Kojak
Milano, Italy

[mick]

Temperature will play a part in your readings , hotter weather = higher readings..so 2 pickups that measure the same @ 20C will measure differently if you were to measure one at 15C and one at 25C.
Not sure how consistent gibsons machine winders are and they could indeed be wound higher or lower..? but this could explain you getting different readings from your sets of pickups..

Mick

[RedHouse]

Mine were taken at 72?

[mick]

Yep , the BB's are different models..I was referring to the classics..

Mick

[RedHouse]

Mine were taken at 72?

Strange, I put in the symbol for "degree's" and it came out in the post as a question mark, hmmm.

...Temperature will play a part in your readings...

You are quite right about DCR readings on pickups, the temperature is a huge factor.

When I wind one, it reads XXX (likely the winding and tension and heat running through my fingers etc) then I set it on the bench for 20 minutes or so and it reads YYY, then I assemble the pickup and it reads ZZZ, funny how the wire is so effected by temperature, and I'm talkin 'bout 400 or 500 Ohms diference sometimes.

As for me, when I finalize a pickup (ready for sale) I wait untill the next morning, hook the DMM leads onto the completed pickup wire (without touching the pickup itself) and use that as the DCR reading.

How do you guy's do it?

{EDIT}

When I posted 72, I meant in degrees Fahrenheit, that would be 22.2 Celcius to my brethern outside the US.

[Joe Gwinn]

Temperature will play a part in your readings , hotter weather = higher readings..so 2 pickups that measure the same @ 20C will measure differently if you were to measure one at 15C and one at 25C.
Not sure how consistent gibsons machine winders are and they could indeed be wound higher or lower..? but this could explain you getting different readings from your sets of pickups.

The temperature coefficient of copper is well known, so one can correct resistances made at any reasonable temperature back to 25 C (77 F) fairly easily.

The temperature coefficient of pure copper is 0.004041 per degree centigrade. Copper wire will be close to this value.

The equation is R = Rref(1+0.004041(T-Tref)).

The temperatures 15 and 25 C are used above, so let's make an example from them:

Assume that the DC resistance of a pickup is 10,000 ohms at 25 C. What will the same pickup be at 15 C?

R15=10000(1+0.004041(15-25))= 9,596 ohms.

The coefficient 0.004041 per degree is usually called alpha, and varies with the precise composition of the metal. I've also seen a value of 0.00393 used, so a direct measurement may be helpful. One can make one's own measurements on a pickup at different temperatures and compute an alpha for the wire one actually uses.

[David Schwab]

Strange, I put in the symbol for "degree's" and it came out in the post as a question mark, hmmm.

This happened to me the other day. The text encoding on the forum software doesn't seem to understand the degree symbol.

That happens when I have my browser set to UTF-8 and get to a web page set to ISO Latin 1 or something, but changing it on my end never made the degree mark into anything other than a question mark.

[RedHouse]

Wow JG, all that math is giving me a headache.

So how does one apply that in the winding process?

Looking at my notebook here I see a coil I did recently had a reading of 3.92k when I finished the wind, after it sat for a while it read 3.89k (room temperature didn't change) but this amount of change shifted the finished pickup from 7.84k down to 7.79k (or so). I can guess why it occurs but just wonder how to apply the math you've posted to getting a adjusted reading immediately after a wind (before letting the coil sit and normalize).

Seems like I'd need one of those laser temperature reading guns to read the coil wire itself.

[Joe Gwinn]

Wow JG, all that math is giving me a headache.

So how does one apply that in the winding process?

By waiting for the temperature to stabilize.

Looking at my notebook here I see a coil I did recently had a reading of 3.92k when I finished the wind, after it sat for a while it read 3.89k (room temperature didn't change) but this amount of change shifted the finished pickup from 7.84k down to 7.79k (or so). I can guess why it occurs but just wonder how to apply the math you've posted to getting a adjusted reading immediately after a wind (before letting the coil sit and normalize).

There really isn't any better way that waiting for the winding to cool off after winding, because the temperature achieved during winding is so variable. This is another reason to wind to a turns count, not a DC resistance. That said, if your winding recipe is followed closely enough every time, it may be possible to figure out what hot resistance will yield a desired cold resistance.

Seems like I'd need one of those laser temperature reading guns to read the coil wire itself.

That would be fun.

[RedHouse]

...There really isn't any better way that waiting for the winding to cool off after winding, because the temperature achieved during winding is so variable. This is another reason to wind to a turns count, not a DC resistance....

Well that's good, it's the way I do it now, both the waiting and the winding-to-turns-count thing.

Wire is so expensive, and specially for spending on the learning process, winding, testing, cutting-off wire and rewinding again, so when a couple 9-lb rolls of 42H Solderon 155 came up on eBay a couple years ago I scored them and commenced to run an extensive bunch of winding learning/experiments/tests since I had tons of the stuff. In fact that's when I decided my original Lollar winder needed to be replaced with something a little better but that's another story.

That's when I realized the virtues of winding to turns count, oh sure I had read it here a million times and still managed to ignore the advise and wind to DCR until those experiments, now I use a turns-count approach always. I wind to a turns count, assemble the coil/coils then measure, then, it is what it is (DCR).

(on a sad note.... I had written down ALL the wind results and parameters of every coil I did over the year or two's experiments in a little notebook for review after the fact...until...my lovely 2 year old neese was over at my house for 2 week summer holiday and thought she'd really like to use my notebook for drawing pictures and tearing out pages when I was away)

...That would be fun.

They have those laser temperature gun's down at the local NAPA autoparts store, it's a little hand held gun-like thingy for like $75 bucks, might have to try it just for kicks, I know a couple guys there and maybe they'd lend me one. I saw a guy using one at a shop once, they seemed to be pretty sensitive to where it was pointed, he showed me the difference in temperature of two places on the same water hose, and several places on an exhaust manifold and pipe.

[NightWinder]

Well that's good, it's the way I do it now, both the waiting and the winding-to-turns-count thing.

Wire is so expensive, and specially for spending on the learning process, winding, testing, cutting-off wire and rewinding again, so when a couple 9-lb rolls of 42H Solderon 155 came up on eBay a couple years ago I scored them and commenced to run an extensive bunch of winding learning/experiments/tests since I had tons of the stuff. In fact that's when I decided my original Lollar winder needed to be replaced with something a little better but that's another story.

That's when I realized the virtues of winding to turns count, oh sure I had read it here a million times and still managed to ignore the advise and wind to DCR until those experiments, now I use a turns-count approach always. I wind to a turns count, assemble the coil/coils then measure, then, it is what it is (DCR).

(on a sad note.... I had written down ALL the wind results and parameters of every coil I did over the year or two's experiments in a little notebook for review after the fact...until...my lovely 2 year old neese was over at my house for 2 week summer holiday and thought she'd really like to use my notebook for drawing pictures and tearing out pages when I was away)



They have those laser temperature gun's down at the local NAPA autoparts store, it's a little hand held gun-like thingy for like $75 bucks, might have to try it just for kicks, I know a couple guys there and maybe they'd lend me one. I saw a guy using one at a shop once, they seemed to be pretty sensitive to where it was pointed, he showed me the difference in temperature of two places on the same water hose, and several places on an exhaust manifold and pipe.

You can always try the smaller keychain size one from Harbor freight? $20- Works nice

[LtKojak]

Do Gibson Burstbuckers have a maple spacer?

Pepe aka Lt. Kojak
Milano, Italy