Pickup resistance

[neepheid]

16 minutes ago, Doctor J said:

Nope, the L1000 is fully passive. The L2000 has a preamp but I run my one passively. It's definitely not needed to give you more than you need. Those pickups are beastly without any help and cut-only controls are just as useful in passive mode.

 

Furthermore, the preamp in the L-2000/2500 is simply a signal booster and the only tone shaping it provides is a non-adjustable treble boost. The 2 band EQ is passive, cut only regardless of whether or not the preamp is engaged (in either mode)

[Boodang]

On 15/01/2023 at 17:03, TheGreek said:

Do I want pickups with high or low resistance?

I would probably say this is the wrong question when it comes to choosing a pickup. 1st up, do you want active or passive pickups, generally speaking active pickups have a greater bandwidth and are brighter. 2nd, single coil vs split coil vs humbucker vs P. 3rd, magnet type, ceramic vs alnico2, 3, 4 or 5. 4th, magnet shape, blade vs pole vs double pole (typically jazz), vs offset pole vs large diameter pole.

After all that if you're going to look at resistance, as in how many windings it has and how 'hot' it is, don't forget to take into account the gauge of the wire.

And that's all you need to consider when choosing a pickup... well almost!

[pfretrock]

2 hours ago, Boodang said:

EMG active pickups have so few windings their output needs boosting with a built in preamp (hence the active part and the need to power them). They do this because the fewer the windings (and thus less resistance) the greater the bandwidth. 

An active EMG pickup will have much stronger content above 3 to 4K than a passive pickup with enough windings to have a strong enough output to not need a preamp boost. 

This of course is a bit of a simplification, as mentioned before, there are many other factors involved not just the amount of windings.

Of course, having tons of bandwidth is not necessary a good thing, as it depends on the tone you want. I used to use EMG pickups and then use a lot of eq to get the tone I wanted... cut the treble, boost some high mids etc. Now I try to get the tone as close as I can at source, ie the pickup. Hence for my Jazz i got some custom single coil pickups made with alnico5 magnets for the neck (for more lows) and alnico2 for the bridge for more mids. For my Sei I got a Bartolini MM made. As a humbucker it has less highs but it's punchier in the lows. 

When I look for a pickup I'm less interested in the resistance than I am the magnet type, single coil vs humbucker, and series/parallel options.

This makes a lot of sense. I was geeky enough to measure the inductance of a Seymore Duncan SPB-3. It was 7 Henries which is typical for a bass pickup with a lot of wire (more turns  = more inductance, and more resistance). This forms a low pass (treble cut) filter in conjunction with the resistance value  (12.5k). I'm not sure why SD quote resonance (10.2kHz) as it is far out of range of a bass , so any peak would be lost due to the low pass effect. There is some data on inductance somewhere for some PUs but adding more wire (more resistance and therefore "hotter output ?" also increases inductance.) There must be a trade off on adding wire to get more output and loss of treble due to added inductance.

 

If you have ever re-wired a series neck humbucker (I had one on a cheap SG copy) because it was too muddy and then wired it in parallel, the inductance drops by a factor of four, you only get an output drop of half (2 coils now in parallel) at the low pass end, and the treble range increases significantly. (by treble range I mean the point at which treble starts to drop off due to the low pass effect of the resistance/inductance). This is the easiest explanation of the effect of inductance I can think of without getting too complicated and geeky. In this case the pickup response rolled off at around 280Hz rather than 140 Hz before re-wiring.

 

If anyone wants to measure inductance (don't all rush!) there is a way of doing it with 2 bits of free software (a signal generator and an oscilloscope) a known capacitor (around 2nF) and a DAW interface. A Focusrite works fine. Not all oscilloscope software works as there needs to be no phase shift between the 2 channels. You have to disconnect the PU also!