Something New Every Day
 

I just had to rebuild my tone circuit, so I bought the parts from Elderly Instruments. While I was there, I spoke with the tech, and he pointed out to me that most of the wiring diagrams for Fender basses on the 'net are actually incorrect, specifically including all the Seymour Duncan diagrams. While these diagrams will give you a working circuit, they are not completely right, and won't allow the circuit to work as intended by Leo. These circuits will overly boost the bass when the tone is rolled off.

For a tighter, more controlled bass, use the correct diagram. The correct diagram can be found at Fender Support.

The main difference is in the wiring of the capacitor, so take note of that. Also, be sure to use the correct wires, as heavier wires will give a noticeably brighter tone. Of course, if that's what you want, then use heavier wires. This can be augmented by using 500k pots rather than 250k.

So, I guess what I learned is that the commercial isn't correct: it turns out that they can, indeed, put something on the internet that isn't true.

Can one of the techy-types can explain this to me?

Easily. Heavier gauge wires offer less resistance. It's the same as with your instrument cable or speaker cable. A longer run necessitates a heavier gauge to retain the top end. In a run the same length, heavier wire/cable equals more brightness/top end.

Could you point out the differences between the fender and Seymour Duncan wiring? I have looked at both for p and j basses and they appear identical. Maybe I'm missing the obvious?

Here's the SD diagram: http://www.seymourduncan.com/images/...501030-100.pdf

Here's the Fender diagram:
http://support.fender.com/service_di...0116C_SISD.pdf

I think this only happens if you are running over 25 ft of cable? the unbalanced signal degrades but I don't think it is significant and the tone difference would be subtle.

Ok. I see it in those two. Some of the other schematics had the same wiring.

It happens in any length of run. Whether you can hear the difference depends on other factors, but it is there.