#1931504 - 04/23/08 10:37 PM
Any guesses re: what's up w/my old, weak, dull P-90?
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Bejeeber
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So we have 2 circa mid 60's Gibson ES-125 TDCs here.
The neck position P-90 on one of them is significantly lower output and duller sounding than the other.
It's also about 1/16" further from the strings than the pickup on the other guitar is, and the pole pieces are extended as far as they can go, so I'm about to start looking around for a P-90 spacer to raise the whole pickup up closer to the strings (I figure the spacers must exist, the bridge PU has one under it!).
So the advice I'm looking for from those in the know here
is whether 1/16" or so could make that much difference in pickup output, or am I just all wishfully thinking and junk?
Do P-90's tend to lose their oomph?
Would having it rewound or whatever you do to fix a P-90 be an expensive drag of a bummer?
This guitar is in good condition, stock except for the tuners (and I do have the originals), so I hesitate to go messin with it's value.
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#1931536 - 04/24/08 02:15 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bejeeber]
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GeoffB
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1/16 wouldn't make that much of a difference. I'd check the wiring & the pots. If that doesn't fix it, get the pup rewound.
G.
_________________________
"When the power of love overcomes the love of power the World will know Peace": Jimi Hendrix
Frank M:Back in the day you could have a trio with two people.
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#1931540 - 04/24/08 02:25 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bejeeber]
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Caevan O'Shite
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I take it these are the "dog-ear" variety, with the (more or less) triangular "ears" on each side, to mount them to the top, via non-adjusting screws? (thus the need for a spacer of some kind, eh?) Otherwise, some height-adjustment would be easier, huh?
The magnets are sometimes accidentally switched around by tinkerers over the years, regarding their polarity. Although, I'd think that the output would be very little to zero if that were the case. Anyways, that's one thing to check if you remove the cover-
-CAREFULLY, if it seems sticky or stubborn, crud-o'-the-ages may have the cover and coil stuck together, and forcing them apart can cause the coil to break and spool away all over the floor and your feet as you look on in abject horror-
-the polarity of the two magnets underneath needs to be going in the same direction, otherwise cancelation and weird, decidedly UN-cool tremolo effects can result.
Raisng the neck-pickup closer to the strings, while lowering the polepieces, will almost certainly increase the aparent output from that pickup. P-90s can be very finicky about extreme low or high polepiece heights, though the problem there is usually one of having them so low that the bottom-ends of the poles are too far below their respective magnets and thus directing much less magnetic-field where you want it- around the strings. (Flush with the bottom would be best, if each polepiece were trimmed to ideal length allowing for the desired height above the cover and being flush with the bottom of the magnet.) Maybe having the poles too high in this case is having a similar effect on the magnets' affecting the strings there above the neck-pickup? I wouldn't necessarily think that would be the result, but...
The magnets do have a half-life of, IIRC, about 30 years or so, meaning their effective strength is weakened by about half every twenty-five- or thirty-years or so. And they can be artificially, if accidentally, degaussed by being too close to powerful electromagnetic fields; a famous case of this happened to the pickups in Andy Summers' battered Tele when he was riding on a train, IIRC Seymour Duncan re-gaussed 'em for him to a vintage-y slightly-weakened state...
Speaking of which, considering the instrument's doubtless high-value, if some least-invasive investigation doesn't reveal the cause of the problem, and thus its cure, I'd strongly consider investing in having no less than Seymour Duncan himself fix it; it'd probably be well worth it, and would probably lessen any decrease in its value due to being worked on...
It may be due to the volume- and tone-pots, and any other components, connected to that pickup; probably not, but I suppose it's possible...
Please, be sure to keep us posted on this, 'jeebs! Best o' luck, alright?
_________________________
~Caevan James-Michael Miller-O'Shite~
_ _ ___ _ _ Leprechaun, Esquire _ ___ _
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#1931564 - 04/24/08 05:11 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Caevan O'Shite]
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GeoffB
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I suggested looking at the wiring & pots first just to eliminate the possibility. Caevan's right - it's unlikely, but you never know, & rewinding the pups is such a big next step.....
G.
_________________________
"When the power of love overcomes the love of power the World will know Peace": Jimi Hendrix
Frank M:Back in the day you could have a trio with two people.
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#1931743 - 04/24/08 10:27 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: GeoffB]
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fantasticsound
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Let's not forget that up until 1961 or so Gibson used various alnico magnets in their p'ups. The Alnico 5 alloy is the most powerful of the Alnico magnet alloys. When they decided on Alnico 5 they turned their magnet pole pieces into a consistent length. Prior to that the alloy used determined the length of the poles in order to even out the consistency from p'up to p'up. I wouldn't be surprised if some of the Alnico 2, 3, etc. p'ups were weaker despite the attempt to homogenize them by pole piece length. I also wonder how each alloy might retain its magnetism over time.
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#1931757 - 04/24/08 10:43 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bejeeber]
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Bill@Welcome Home Studios
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My guess would be that it is the distance.
I also want to mention that my luthier often sets my pickups further fromt he strings than I would if I was ajusting them myself, just by looking at them. I've never asked him why, I trust that he knows what he is doing, and I'm usually thinking about other things when I see him, so I forget to ask. But I'm wondering if he uses a meter or something to get an average output level, using that to dtermine the distance in order to provide the most even tone across all of the strings, rather than the loudest sound possible. Just a thought... no science behind it or anything. he definitely balances the levels between the two, and they always sound nice when he is done, so long as I don't get the urge to 'fix' anything.
Bill
_________________________
"...it's easier than hitting the kids, and almost as much fun..."
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#1931785 - 04/24/08 11:22 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bill@Welcome Home Studios]
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Bejeeber
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THANKS fer the insight guys, this sort of thing is why this forum is the internet's best kept "secret". 
Cavean, Geoff, Neil, Bill, whatta tag team of guitar/Gibson expertise! 
And yes Cavean, these are indeed the dog ear/triangular non adjustable pickup height type P-90s.
I guess I'm looking at taking this guitar to a professional then, seeing as how I'm a clutz and doofus about tech stuff, and don't wish to experience any abject horror as Cavean describes! 
It would have been more accurate BTW for me to say the guitar is in excellent, not just good, condition.
Despite being a vintage Gibson though, last time I checked, these ES-125s certainly aren't commanding the big'ol bux that Les Paul Juniors etc. from the same era are, so I don't know that pulling in Seymour Duncan himself would be financially justified, although that's a heckuva idea!! 
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#1932474 - 04/25/08 02:55 PM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bill@Welcome Home Studios]
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fantasticsound
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My guess would be that it is the distance.
I also want to mention that my luthier often sets my pickups further fromt he strings than I would if I was ajusting them myself, just by looking at them. I've never asked him why, I trust that he knows what he is doing, and I'm usually thinking about other things when I see him, so I forget to ask. But I'm wondering if he uses a meter or something to get an average output level, using that to dtermine the distance in order to provide the most even tone across all of the strings, rather than the loudest sound possible. Just a thought... no science behind it or anything. he definitely balances the levels between the two, and they always sound nice when he is done, so long as I don't get the urge to 'fix' anything.
Bill
There is science behind it, though. 
Putting your p'ups too close to the strings actually allows those powerful magentic fields to dampen the ability of the strings to vibrate, reducing sustain! Putting powerful p'ups up close to your strings actually defeats half the purpose of having strong p'ups at all.
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#1932493 - 04/25/08 03:30 PM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bejeeber]
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mdrs
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BeJeeb...
How long have you had these guitars? Was this one pu always farther away from the strings? Was it always duller sounding? Or, is this a change in the way it sounds??
First thing I'd do is find a luthier/guitar tech who has experience with vintage guitars. Those are lovely old guitars, and I'd take care to be certain that anyone that touched it treated it properly. They are worth a lot of money, and likely will increase in value over time, being quality vintage Gibsons.
I have some '50's and early '60's Gibsons with P-90's. I've not had any problem with the volume of any of those. So, I don't think it's a case of the pu "wearing out", or losing it's "magnetism". While I am NOT a P-90 expert, I have heard that the height of the pole pieces were adjusted to balance the volume of each string, and the relative volume of each pu in guitars with two P-90's. So, it is possible that this pu was set up farther away from the strings to give a duller tone purposefully.
As I said, I'm sure not a P-90 expert, and have never experienced what is going on with your guitar. Find the right luthier, and he'll diagnosis it for you.
BTW....Seymour Duncan probably is not exorbitantly high priced for fixing an old pu, assuming that that will be something you need to look into. Lindy Fralin is also a know expert at repairing old pu's. As I recall Bribaby had an old Tele pu repaired by Lindy. Perhaps he'll see this and chime in.
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#1932542 - 04/25/08 05:54 PM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: fantasticsound]
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Caevan O'Shite
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Putting your p'ups too close to the strings actually allows those powerful magentic fields to dampen the ability of the strings to vibrate, reducing sustain! Putting powerful p'ups up close to your strings actually defeats half the purpose of having strong p'ups at all.
One thing about P-90s, though, as opposed to Fender-style single-coil pickups: their magnets- bar magnets- are underneath the bottom of the pickup, with their polarity running 'sideways', quite removed from the strings, in comparison with Fender-style single-coils, which point a slug-magnet's polarity right at each string, and quite close and directly beneath them! P-90 stylees are much less likely to cause that sort of trouble.
_________________________
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_ _ ___ _ _ Leprechaun, Esquire _ ___ _
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#1932603 - 04/25/08 10:42 PM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Caevan O'Shite]
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Bejeeber
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Sheesh Cavean you are a freekin fountain of info about this stuff. That sideways polarity is something I definitely hadn't heard about before. 
Another tidbit of info about the guitar: according to my research, it's a '67.
Mdrs, we've had the stronger pickup guitar for a bout a dozen years, the weaker one for a few years. I actually don't know if the pickup output has changed while I've owned it, because I've just gotten to seriously plugging 'er in and doing comparisons, before that it was mostly some occasional unplugged twanging.
Agreed that an expert oughta give it a hands on assessment, and even if distance from strings doesn't entirely account for the low output, it just seems like it'd be better to have that spacer under the pickup so those polepieces don't have to be all craning their necks trying to get close enough to the strings???
Ya think a spacer under the pickup like that could affect resale value, and that if I ever had to sell it I'd be better off removing it? I'd hope that a non-invasive, easily reversed mod like that wouldn't be an issue for any reasonable buyer....
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#1933011 - 04/27/08 05:25 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bejeeber]
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Bill@Welcome Home Studios
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and could it be an electronics issue? Pot values vary, caps go bad, resistors change over time.... I am just saying that, withput removing the pickup from the circuit and testing it, you've no way of knowing what is really at issue here.
When I see old pickups sold, the sellers are usually giving ohmage readings. I don't know how, or what that tells one, but it does remind us that pickups were often wound with different materials and gauges of wire, sometimes in different ways, and varying numbers of turns of wire, as manufacturers were experimenting with designs and with expense issues. It is not unusual to find Les Pauls from the same year sounding far different from each other, so why would we expect all the pickups to sound the same?
As I said before, I'm thinking that the major issue is the distance. But there could be other factors.
Bill
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#1936146 - 05/02/08 05:35 PM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bill@Welcome Home Studios]
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Caevan O'Shite
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Heeby-Jeeby, what's it beeby?
What's the bird's-eye low-down on this caper so far?
_________________________
~Caevan James-Michael Miller-O'Shite~
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#1942488 - 05/15/08 08:40 AM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Bejeeber]
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Caevan O'Shite
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Soooo... What's the latest, Bejeeberer? What's the bird's-eye low-down on this caper? "Pee-Ninety"? "Soapbars"? Izzatt what the kids are caling it these days!?
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#1942673 - 05/15/08 03:18 PM
Re: Any guesses re: what's up w/my old, weak, dull P-90?
[Re: Caevan O'Shite]
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Bejeeber
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What's the bird's-eye low-down on this caper?
Well after puttin y'all thru the ringer over this one, yesterday I started leaning towards just favoring the other ES-125 in our 2 guitar Gibson collection  , and letting this baby back burner a while longer.
This is after another acoustic comparison test between the 2. They respond differently alright. Different trapeze tailpiece "blocks" and other little things like that I figure are accounting for some of it, though for all I know set up may be more responsible.
The '65 sings so sweetly with bends on the B string, not as much on the G. Opposite is true for the '67. The '67 is louder, more resonant, acoustically. If anything I may find the '65 a little more responsive for range of bendy expressiveness.
If we didn't have that '65 sittin here I probably woulda got on the case with the '67 weeks ago. Yep, excuses, excuses.
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