Bass pickups

[Andy Scott]

On a PJ bass both pickups on full. why do they cancel each other?

[dmccombe7]

What do you mean cancel each other ? 

Do they shut off completely or just the tone changes ?

Active or passive ?

Some more info would help identify what the issue might be.

Dave

Edited April 5, 2021 by dmccombe7

[fretmeister]

Insertion Loss?

[MrDaveTheBass]

Could be out of phase?

[Reggaebass]

Welcome Andy 👍, what bass is it 

[Crawford13]

When you say cancel each other out, do you mean tonally? 

I have a couple of PJ basses (it's my favourite set up), however in truth I don't believe you can really get a P bass sound, or a J bass sound out of them. 

I tend to look at the tone on offer as the warmth of the P bass with a little added clarity for the J Pickup.

[ubit]

Are you sure it's not just the bass pick up that  is overwhelming the neck pick up?

[Jus Lukin]

-

Edited March 14, 2022 by Jus Lukin

[Phil Starr]

11 hours ago, Andy Scott said:

On a PJ bass both pickups on full. why do they cancel each other?

Are you just talking about the change in tone?

If so it's fairly simple. The strings don't just vibrate like a skipping rope. There are loads of harmonics so at any one point in time the string can be moving forwards at one point and backwards a little further up the string.

The pickups sample only the movement above them. If the movement is opposite the voltages will cancel and the combined output will be reduced. A millisecond later the movement and output will be back in phase. This is dependant upon frequency and how far apart the pups are but we normally hear this as a midrange suck out.

I am

 such a nerd

[Reggaebass]

When I first got my 1998 P bass special, which I bought because I couldn’t resist the candy apple red finish, I didn’t actually like the tone, I’d been playing precisions and jazzes before and this didn’t sound like either with the pickups solo at firs t, but after a fair bit of tweaking you can get very close to a P or a Jazz sound if you want it, I think they just take a bit of time to get used to,  it’s by far one of my favourite basses, lots have come and gone but this is going nowhere 🙂

[yorks5stringer]

I had this on a PJ Bass, the trick is just to take a touch off either pickup with the tone control leaving the other one on full.

[Reggaebass]

38 minutes ago, yorks5stringer said:

I had this on a PJ Bass, the trick is just to take a touch off either pickup with the tone control leaving the other one on full.

Yeah I found that, backing either pickups off just a touch alters the sound  considerably , then I use the tone knob to dial in what I want further 

[Crawford13]

25 minutes ago, Reggaebass said:

Yeah I found that, backing either pickups off just a touch alters the sound  considerably , then I use the tone knob to dial in what I want further 

The other route you could go down if you like everything else about the bass is install a blend pot and have volume, blend, tone, as your controls instead of volume, volume, tone.  

I find that this configuration makes it easier and quicker to find a usable tone, and not have jumps in volume if you are making changes on the fly. 

[dmccombe7]

2 minutes ago, Crawford13 said:

The other route you could go down if you like everything else about the bass is install a blend pot and have volume, blend, tone, as your controls instead of volume, volume, tone.  

I find that this configuration makes it easier and quicker to find a usable tone, and not have jumps in volume if you are making changes on the fly. 

Pan control is definitely an improvement but i find with active basses the minute you move from dead centre it has quite a dramatic tone change probably the reverse of what the OP has mentioned. 

I tend to keep my basses on equal settings. My Jazz i usually have both volumes full on. With my Thumb, Fender PJ and Sandberg  VM4 i tend to keep pan in centre position.  If i move the Fender or Sandberg just slightly towards the rear pickups it does give a very "jazz focused" tone. (good for jazz type songs) and going the other way the bass becomes very much more P sounding. I dont find that much change between just off centre and full on P position to be honest. 

With my Warwick i think i need to check that out as the bridge pick up is a lot more quiet than the neck pick up since fitting the MEC pre-amp from warwick few yrs back. It didn't sound that way with the original EMG preamp that failed. The MEC was the only option i had at the time if i wanted to keep standard Warwick.

Think there's a Gain adj on each pick up or maybe its just pick up height. If not it will be taken to an expert.

Dave

 

[Crawford13]

5 minutes ago, dmccombe7 said:

Pan control is definitely an improvement but i find with active basses the minute you move from dead centre it has quite a dramatic tone change probably the reverse of what the OP has mentioned. 

Yes you are quite right, I was guessing that the OP had a passive bass as it sounds like he has VVT, but if active preamps minor tweaks can make massive differences. 

I shouldnt assume 😂

[Reggaebass]

31 minutes ago, Crawford13 said:

The other route you could go down if you like everything else about the bass is install a blend pot and have volume, blend, tone, as your controls instead of volume, volume, tone.  

I find that this configuration makes it easier and quicker to find a usable tone, and not have jumps in volume if you are making changes on the fly. 

I’m quite happy with mine , but I totally get what you’re saying about changing it on the quick if you’re playing live , unless you know exactly where the setting is that you need, the VBT would be quicker 

[dmccombe7]

34 minutes ago, Crawford13 said:

Yes you are quite right, I was guessing that the OP had a passive bass as it sounds like he has VVT, but if active preamps minor tweaks can make massive differences. 

I shouldnt assume 😂

Absolutely no apology necessary. I think you are right that it is a VVT by the way he has described it. I've no experience of a passive PJ.

Dave

[dmccombe7]

I was opening the OP might have come back with some more info on bass and what exactly is happening.

Appreciate he/she is a newbie.

Dave

[JeezyMcNuggles]

On 05/04/2021 at 14:00, Andy Scott said:

On a PJ bass both pickups on full. why do they cancel each other?

They don't cancel eachother, there's a "phasing phenomenon" that occurs in all instruments with two pickups. In most cases, the hotter one wins (whichever reads less ohm) and you retain more of that one's character. But, the end result is ultimately determined by how those particular pickups work together. A PJ set (from one manufacturer, sold as a set) will work the best together. In all cases. Mixing and matching (either entirely different makes all together, or even purchasing a set as individual pickups) is always a crap shoot. Sometimes, you get straight garbage. Sometimes, you can't hear any difference when adding the bridge. Sometimes, it works out great. Phasing is a funny thing. When a set works together well, you'll retain the majority of the split mid range, and just add the treble and definition of the single. Or, manufacturers will make them scoop more mids out to simulate a jazz bass set up. It all depends on the pickups.

 

But, to answer your question simply,

         Phasing

 

JN

[EMG456]

They could just be wired wrongly.

I rescued an old Aria Jazz Bass a few years back and when I put it all back together again the pickups were wired out of phase. The wiring was correct according to the colours of the pickup wires but the end result was definitely out of phase. Reversed the phase of one of the pickups and that sorted things out. As far as I know, the pickups were original to the bass so must have been manufactured and installed like that.

[StickyDBRmf]

I had PJs on my Pedulla and I changed over to blend knob. I still hated the sound of those two together. And I had P and J basses.

[NancyJohnson]

In phase/out of phase/whatever.

With a passive dual pickup system, there's always an inevitable roll off when both the pickups are open (I'm sure someone here will be able to back this up with an equation to support the reasoning)...also worth remembering that despite the allusion the pickups are in isolation, everything is still linked together in the loom, so you're reliant on the pots working 100% with zero bleed (unlikely).  The only way to isolate would be a manual pickup switch (like a Les Paul), where you're physically removing the pickup from the circuit.

I installed a Geezer Butler PJ set into a bass recently (these are solderless/plug and play); following installation, either of the pickups was louder in isolation than the other, but played together the output dropped.  Nothing wrong/incorrect with the wiring, it just happens.

It's then simply a case of reverting to pickup height to balance things out to your own preferences should you wish to play with everything open.

Mine's all sorted...100% happy.

[neepheid]

I can't say I've ever liked how two pickups together sound on a 2 pickup bass.  Neck on its own - great.  Bridge on its own - I don't like it much but I appreciate the honky, nasal thing it's going for and it does have character.  Both together has always sounded "meh" to me, a bit gutless, subtracting rather than adding even when in phase.  A less good neck pickup, basically.  Not a fan.

There are exceptions to every rule, but they are technicalities.  Like the two inner coils of both pickups together on a G&L L-2000 - that's a sweet sound but they're close enough together that they might as well be a third, central pickup when you're using it that way.  Or the Gibson G-3, which gives you no option without rewiring to use the pickups individually, either 1+2, 2+3 or 1+2+3.  Even with that one, I favoured 1+2 over 1+2+3 so I think it fits the theory in its own way.

It's why I love my Jack Casady (which has three, progressively more aggressive versions of the same core sound), why the volume on the bridge pickup on my Les Paul is always off so the selector switch ends up as a kill switch and why if I ever want to get a really special bass in the future (i.e. spending more than a grand), it'll likely be a G&L L-1000.

[How1]

I know this is an old thread, but I think I know what the OP means.
 

I’ve just removed the preamp from my Charvel PJ and installed the DiMarzio pickups passively with VVT setup. With both pickups on full it completely cuts out the p/neck pickup out and alters the sound of the bridge pickup (makes it more trebly). If I roll the P pickup back a tad it actually gives the bridge pickup a bit more bass! If I start with the bridge pickup full, and then slowly increase the P pickup, it does absolutely nothing until it’s on full and has the above effect off cutting bass from the J pickup.

 

I’ve checked the wiring again and again against the DiMarzio diagram and it’s all wired correctly and both pickups work as they should when used one at a time. It makes no sense.

[Hellzero]

Your pickups are out of phase, it can happen even with the best makers.

 

Simply reverse the phase of one pickup by inverting the hot (+) and cold (earth or -) wires and it should work normally.