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Author Topic: DC resistance and balance  (Read 7259 times)

BazC

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DC resistance and balance
« on: September 18, 2013, 03:15:52 PM »
Excuse my ignorance, I have been reading up on DC resistance and appreciate that DC resistance doesn't necessarily compare directly to output because of many other factors. I gather that all other factors being equal generally a higher DC resistance will result in a hotter and darker pickup - true?

That being the case I am a little confused about the DC resistance on certain pairs of pickups. I would assume that though some people might want a gain boost on the bridge mostly you would want the neck and bridge pickups to be roughly balanced in output. Like the '55 stagger at 6.8 and 7 KΩ however some sets have very different values for neck and bridge like Flat '50 at 10.6 and 6.8 KΩ or Piledrivers at 13.1 and 7.4 KΩ

So do the Flat '50s and Piledrivers have bridge pickups that are much hotter than their neck pickups or is that oversimplifying?

Philly Q

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Re: DC resistance and balance
« Reply #1 on: September 18, 2013, 05:50:31 PM »
Big differences in DC resistance like the ones you quoted are due to different gauges of wire being used in the pickup coils.
 
If you look at the Strat and Tele pickups you'll notice that the vintage models using 42 AWG wire have a DC resistance starting around 5.5k and going no higher than about 8k, that's as much wire as you can squeeze onto the coils!  Then the hotter models, using thinner wire, suddenly jump up to 12k+.  There's almost nothing between 8k and 12k (the only exception being the Flat 50 bridge at 10.6k).

It doesn't mean there's a big jump in output, just that thinner wire has much higher DC resistance.
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Andrew W

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Re: DC resistance and balance
« Reply #2 on: September 18, 2013, 10:21:43 PM »
I'm guessing here but it could also be that a string will be vibrating more over the neck pickup than over the bridge (as it's closer to the bridge) so you might want a higher output bridge humbucker to balance out the perceived volume out because of the difference in output from the string. Maybe?

King Zog of Albania

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Re: DC resistance and balance
« Reply #3 on: September 19, 2013, 12:34:16 AM »
Quote from: Bill Lawrence
DC resistance is NOT a power rating; it is the resistance of the wire in a pickup's coil at zero hertz, something that only occurs when the guitar isn't played. If some marketers use DC resistance as a power rating for an AC device, like a pickup, then they only show their ignorance.

http://www.billlawrence.com/Pages/Pickupology/output_sonic_evaluation.htm

Quote
DC resistance measurements are widely used as a gauge of the “output” of passive magnetic pickups. This use of DC resistance is both technically incorrect and often misleading; to find out why, read on

http://www.planetz.com/pickup-dc-resistance-and-output-levels/

Quote
... manufacturers and therefore guitarists become obsessed with the DC resistance, measured in kilo ohms ( k ), of guitar pickups. This measurement is pretty much useless when assessing a pickups power as all it does is tell you how much power drop their is over the particular length of wire used to make the pickup, it does nothing. NOTHING I TELL YOU, to give any true view of the power output of the pickup.

http://www.warmanguitars.co.uk/guitar_pickups_comparison.html

http://www.lollarguitars.com/blog/2010/04/how-important-is-guitar-pickup-dc-resistance/

BazC

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Re: DC resistance and balance
« Reply #4 on: September 19, 2013, 08:20:14 AM »
Thanks for the info guys, I think I get what you're saying but I'm still confused lol!

Like I said in my first post I realise that DCR is not an indicator of output between pickups of different designs but when all other factors are equal - bobbin size and material, base plate size and material, wire type and gauge, wind density and probably a load of other stuff - DCR will TEND to indicate output and brightness in broad terms.

What is confusing me is not the difference between different types of pickups but the difference between the neck and bridge pickups in the same set which use the same materials and wire gauge and wind density.

AndrewW - I think what you say is true that there is more energy in the string nearer the middle but that is normally compensated for by having the neck pickup lower than the bridge pickup.

In the '55 stagger the neck and bridge have nearly the same DCR as I would expect but on some other sets the neck and bridge have very different DCR despite having the same wire gauge and wind.

So does that mean that the bridge pickup of the Flat "50 is much hotter than the neck pickup?

Maybe the simplest way to put my question is-

Why make most pickup sets have approximately the same DC resistance in the neck and bridge pickups but on other sets give the bridge pickup a much higher DC resistance?

Dave Sloven

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Re: DC resistance and balance
« Reply #5 on: September 19, 2013, 10:43:22 AM »
I've noticed this mainly on the metal-oriented pickups.

I'd say that the big bridge output is to give the power for chugging palm mutes and riffing, while the neck has to be lower output to avoid overdriving the high-gain amps these guitars are often used with.  As the resistance value on the neck increases generally it becomes more difficult to get true cleans on the neck pickup.  As most metal players don't use the bridge for cleans, even if they use it sometimes for leads, they are prepared to sacrifice clean leads on the bridge in return for more power.

This would seem to be the answer from the point of view of why someone would want a lower value at the neck or not be worried by the fact that the neck was not as hot as the bridge.  Also the hotter neck compensates for the fact that the strings seem quieter at the bridge.

Anyone who has played a Fender Jazz bass with two identical pickups at neck and bridge knows that the notes get 'thinner' as your picking hand approaches the bridge and when you use the bridge pickup only. 
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BazC

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Re: DC resistance and balance
« Reply #6 on: September 19, 2013, 08:30:48 PM »
Cheers for that Agent Orange, that would certainly make sense in some pickup sets but the example of the Flat '50 pickups which I posted, the set is actually a vintage style Tele set based on Broadcaster pickups.

Maybe an email to BKP would be my best bet to sort this question out.

BazC

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Re: DC resistance and balance
« Reply #7 on: September 26, 2013, 11:23:30 AM »
Well I emailed BKP and Tim was extremely helpful. The Flat '50 neck and bridge pickups are wound with different gauge wire which explains the difference in DCR. Apparently they're nicely balanced as you'd expect vintage style pickups to be.