Old P90's

[popsaka]

Hi kids... so does anyone know what the impedance should be on a genuine old (or oldish) Gibson square cover -no triangles- black plastic with steel bottom (base) P90?? The unit in question meters a hair over 8k. ...and the PU is slated to go into the treble/bridge position on my very old Japanese copy of a LesPaul special made from a single giant slab of some dark mahogany colored hardwood*. Thanx in advance

*stranger things have been known to happen!

[popsaka]

...I guess nobody knows.......(?)

[newey]

Sorry, popsaka, I missed the post first time around. 8KΩ sounds about right.

BTW, the "triangles" are called "dogears" . . .

[1150lefty]

This is an old post, I know. Just had to bump it to add knowledge. Some "old" Gibson P-90's can be in the high 4 Henries (wow) for a neck, and I haven't comfirmed the bridge partner isn't close. Mostly, you'll find the neck in 6-7, and bridge is somewhere around 8. This is based on my own research. They should all be the same pickups used on all class models for the year, i.e. Standard, Custom, etc. The models may be different, so you might get a pickup installed that didn't go on that model that someone had laying around at the time. The original P-90's had Alnico magnets.

My clone measures 7.6 neck, and 8.4 bridge. They will soon be replaced by Wilkinsons 8.5 and 9.2(?), just because I got a killer deal on them. We'll see if I don't put the neck pickup back - it has a sweet tone, while the bridge needs a little kick in the pants.

[yakkmeister]

Apr 16, 2012 9:50:25 GMT -5 1150lefty said:

This is an old post, I know. Just had to bump it to add knowledge. Some "old" Gibson P-90's can be in the high 4 Henries (wow) for a neck, and I haven't comfirmed the bridge partner isn't close. Mostly, you'll find the neck in 6-7, and bridge is somewhere around 8. This is based on my own research. They should all be the same pickups used on all class models for the year, i.e. Standard, Custom, etc. The models may be different, so you might get a pickup installed that didn't go on that model that someone had laying around at the time. The original P-90's had Alnico magnets.

You're either saying that though 'old' P-90's are 4 Henries, the newer ones read upwards of 6 to around 8 Henries or you're mixing units... or perhaps you got Ohms and Henries mixed up? I assume it's mixed units?

Most of the reason for the variance in early production pickups is due to production methods. The very early winders didn't have turn counters on them and, subsequently, pickups tended to be wound until they were 'full.' Being hand-guided, there were also numerous gaps and other inconsistencies. Differences in guage and laquer, time and quality of potting (if any) were other variables. It's just as easy to find a 50's era pickup that sounds like rubbish as one that sounds great.

Paraphrased from The Guitar Pickup Handbook by Dave Hunter.

[1150lefty]

Thank you Yakk! Maybe I should have thought of checking the info from BOOKS instead of aimlessly searching people's misinformation on the innerweb. It was also my understanding that Henries was Ohm x 1000. Or something like that? (My memory is gone and I'm trying to rebuild it along with leaning to play again.)

[newey]

It was also my understanding that Henries was Ohm x 1000. Or something like that?

Nope, Henries and Ohms are two different units of measurement for two different properties -inductance and resistance, respectively.

Pickups are, in fact, inductors, and therefore have an inductance ("L", symbolically speaking). However, a regular multimeter doesn't measure inductance, so usually a resistance measurement is what one sees quoted for pickups.