Why SD and home-made are different?

[salvarsan]

The SyscompDesign doc uses a low inductance air-core coil for driving the pickup so that it's self-resonance is far above the pickup's. That way, the resonances won't interfere with each other.

You might do an impedance plot of the driver coil to see if this is a problem.

Syscomp Design's document is:

Measuring Frequency Response and Impedance of Guitar Pickups

[David Schwab]

Get an SD 'bucker and listen to it and measure it; then take off all the wire, rewind it your way, and see how it sounds and measures. Then you'll know if it's in the materials or in your wind technique and wire.

Eliminate variables to learn what's going on. That and learning to diagnose problems are the two hardest things for electric luthiers to do.

Just for the experience, I decided to replicate a Duncan JB. I used commercially available bobbins and parts, I measured magnets to get a close match, etc.

My version was much darker sounding, and that's already a fairly dark pickup. I didn't use the exact parts from the JB, since I didn't own the pickup, but the parts were consistent with what's common on pickups, and I had used these parts in the past, so I was familiar with them, and made a number of nice sounding PAF style pickups.

So I have to assume it was my winding pattern/technique and not the parts.

[csjang]

Thanks for the tip, Salvarsan!

Finally, I found it is a COUPLING ISSUE as Mike mentioned. I tried the same measurement without slugs in the driver coil and it produced the second peak with home made ones, while SD showed the scoop beyond 10kHz!! I am so relieved, because I have been thinking I had messed up with my winding or wiring...

Thanks all for the comments and advice!

[Rick Turner]

The industry standard is to use a relatively low impedance air core driver coil.

[Jim Darr]

Finally, I found it is a COUPLING ISSUE as Mike mentioned. I tried the same measurement without slugs in the driver coil and it produced the second peak with home made ones, while SD showed the scoop beyond 10kHz!!

If both original tests were done exactly the same on both the hand wound pickups and the SD factory pickups, shouldn't the original results be valid (only as a comparison between the two) assuming there was no other variables between the two original tests?

When you changed the driver coil to the correct air coil, did you also retest the SDs? If so, how did it compare to your original results and then to each other?

Can you post before and after plots for hand wound and factory?

Most importantly, how does your pickup sound compared to the SD?