DIY Pick up testing

[Antigua]

You might want to read all 600 pages of volume 1 of PotEG before final evaluation.

Your condescending tone is getting to be too much. First, I know that there are not 600 pages of 1200 total pages devoted to this subject. There are not even that many pages dedicated to the guitar pickups. Second, PotEG is in German, with small parts translated, and I have even worked on making translations myself which you can see here http://www.echoesofmars.com/zollner/idr/?page=1 . I have been in contact with Gitec about translating more of the book by capable translators. I do put real effort into this.

[Helmholtz]

Your condescending tone is getting to be too much. First, I know that there are not 600 pages of 1200 total pages devoted to this subject. There are not even that many pages dedicated to the guitar pickups. Second, PotEG is in German, with small parts translated, and I have even worked on making translations myself which you can see here http://www.echoesofmars.com/zollner/idr/?page=1 . I have been in contact with Gitec about translating more of the book by capable translators. I do put real effort into this.

I said don't judge before you have read all.

I am respectful to people who treat me respectfully.

[rjb]

...my goal is to make a noisless PU, which has the size and character of the original P Bass single c. PU. If it has a bit thicker sound thats ok.

Although I once met someone who owned an original Telecaster Precision bass, I never met the bass itself.
Can you define the character you seek?

Have you tried the unmodified pickup before swapping magnets and installing asymmetric rails?
Speculating, calculating, and tinkering can be good clean fun- but it appears you may be seeking a solution to a problem you don't have.

...I have to match better the polepiece heights

If the tone with the original rails happens to be OK, but the string-to-string output is unbalanced, you could simply notch the rails under the louder strings- in the manner of certain "Charlie Christian" style pickups. (Of course, you would then apply some kind of rust protection to the filed sections.)

-rb

PS- OOPS. I wrote this offline while #15 was posted. Congratulations!

[Antigua]

I said don't judge before you have read all.

I am respectful to people who treat me respectfully.

Well it is German, and I don't speak German, so cut me some slack.

[J M Fahey]

I am respectful to people who treat me respectfully.

Said the man with the short fuse .

[Helmholtz]

Said the man with the short fuse .

Meaning what? In plain simple english, please.

[rjb]

Say, did you guys hear?
Okabass made a nice-sounding pickup.

-rb

[okabass]

Although I once met someone who owned an original Telecaster Precision bass, I never met the bass itself.
Can you define the character you seek?

Have you tried the unmodified pickup before swapping magnets and installing asymmetric rails?
Speculating, calculating, and tinkering can be good clean fun- but it appears you may be seeking a solution to a problem you don't have.


If the tone with the original rails happens to be OK, but the string-to-string output is unbalanced, you could simply notch the rails under the louder strings- in the manner of certain "Charlie Christian" style pickups. (Of course, you would then apply some kind of rust protection to the filed sections.)

-rb

PS- OOPS. I wrote this offline while #15 was posted. Congratulations!

I naturally tried original type PU. (My friend has all original '56 P Bass) Several PUs as a matter of fact. At least a dozen single coils, wound from 5,7 kΩ to 9 kΩ, different magnets, different strength. Stack- and spit coil- types.

The character is not easy to tell, cause the bass is surprisingly versatile. I like certain rawnes, originality compared to split coil P Bass. Keith Ferguson with Fabulous TB, Dusty Hill with ZZ Top, Stings P bass sound...
As I said my goal: single coil sound, humbuckers "noise".
I tried stack, split coil type Humbuckers. They sound kind of lame to me.
I tried Dimarzio's Fast Track 1. That China rail PU. Then I found Seymour D. Vintage rails patent which has partly cut rails. I cut China PU's rails, but I feel it still has some "mud" . Then I found that Yamaha patent, with comb-type rails. I feel it is the best of the rail types I tried. But lets see...or listen.
I potted the PU and put a vintage correct cotton string. Must clean it a bit some day.
https://www.dropbox.com/s/axzj5bhonb....50-1.jpg?dl=0

[Helmholtz]

Said the man with the short fuse .

(Google knew the phrase)

Thanks, will (re)consider.

[Joe Gwinn]

How do think it works, if I cut for example a 1-2 mm slot to the poles?

Probably no effect. What works is to laminate the pole blades: Instead of one mild steel sheet of say 2mm thickness, use two identical sheets of 1mm thickness, insulated from one another, and so on. Tune by ear.

[okabass]

Probably no effect. What works is to laminate the pole blades: Instead of one mild steel sheet of say 2mm thickness, use two identical sheets of 1mm thickness, insulated from one another, and so on. Tune by ear.

Now I 've been listening more, the high end could be more warm (add a little cap?). It has kind of sizzle. In what direction laminated blades will go? Part of the '51 PU's sound I like is kind of brutal attack because of single ca. 5mm magnet pole per string. I may try little screwheads as poles.

Ps. Got a idea to use screws as pole pieces, to make it less sizzly. I tried with a 7ender bass PU screw and magnet bar only. I got ca. 300 Gs at the screw head. What do you think: is that too little.
I checked some Gauss values, it is not very far from P-90 (Alnico II). Or PAF (Alnico II or V).

[Helmholtz]

What kind of control circuit do you use? Lower pot resistance values will reduce excessive highs.

[okabass]

What kind of control circuit do you use? Lower pot resistance values will reduce excessive highs.

Normal P Bass: 250 kΩ vol pot and tone. Very clever simple idea. Must try.

[Antigua]

Normal P Bass: 250 kΩ vol pot and tone. Very clever simple idea. Must try.

250k is about as low as you can reasonably go with off the shelf parts, so an alternative to forcing a lower Q would be a 500k trim pot, so that you can dial in some ideal amount of additional parallel resistance. Turning down the tone pot also lowers the Q, so this mod is roughly the same as forcing "8" or "9" to be the maximum tone setting, depeding on the value of resistance.

If you wanted to see what was happening for certain, it's possible to see the resonant Q with a bode plotting oscilloscope, such as the Velleman PCSU200, or you can even create a model with LTSpice, which is free, plug in the values of the pickup and simulate different loads. That latter wouldn't model the eddy currents of different screws, but it would reveal the change you get with, say 250k versus 500k pots. If you've never done either of these things, there a learning curve involved, but it's worth knowing that trial and error isn't the only option available.

[bbsailor]

250k is about as low as you can reasonably go with off the shelf parts, so an alternative to forcing a lower Q would be a 500k trim pot, so that you can dial in some ideal amount of additional parallel resistance. Turning down the tone pot also lowers the Q, so this mod is roughly the same as forcing "8" or "9" to be the maximum tone setting, depeding on the value of resistance.

If you wanted to see what was happening for certain, it's possible to see the resonant Q with a bode plotting oscilloscope, such as the Velleman PCSU200, or you can even create a model with LTSpice, which is free, plug in the values of the pickup and simulate different loads. That latter wouldn't model the eddy currents of different screws, but it would reveal the change you get with, say 250k versus 500k pots. If you've never done either of these things, there a learning curve involved, but it's worth knowing that trial and error isn't the only option available.

Agree!!!

But, make sure you use a capacitor equal to the capacitance of your coax cable feeding your amp. Also, add a 1M ohm resistor in parallel with the pot to represent the amp input loading. This will get what you see on the Bode Plot closer to what you actually hear when plugged in to your amplifier.

One interesting experiment is to build the Tillman active FET buffer located in the instrument end of the coax cable plug. This device puts from a 5M to 10M ohm input load on the pickup thus eliminating the effect of cable capacitance and reduces amp loading and requires no instrument mods as it is all external to the instrument. What you will hear is a brighter sound with a higher resonance and higher Q at the resonant frequency. Part of the experiment is to listen to what effect varying the volume pot has on the tone.

Enjoy.

Joseph J. Rogowski