Jazz pickups question

[Sharkfinger]

So I've been wondering this for a while and it's about time I asked to see if anyone has an answer:

When both pickups on a jazz bass are up full, there seems to be a noticeable dip in the mids. I can only surmise that it has something to to with phase cancellation. If this is the case, what can be done about it and more importantly, why isn't it done?

I remember Fender had that S1 circuit a while back. Did that have anything to do with it?

TIA

[Geek99]

No - they all do that. Try 100% bridge 80% neck

[zero9]

Not all J pickups are the same. Fender single coil J pups certainly suffer from this, but my EMG's don't.

[DorsetBlue]

The S-1 switch/mod just wires both pickups in series, boosting their output. In normal mode, the pickups are in parallel and as you state, there is an out of phase loss when both pickups are at 100%. Personally there is something really cool about hitting a note and trimming one of the volumes down until you hear that sweet point, it is really prominent on my VMJ.

Edited July 22, 2013 by DorsetBlue

[- Matt -]

Agreed, the only way to stop the phasing would be to install a series / parallel switch. But the phasing "quirk" is part of the vibe of the J bass.

[Dingus]

The degree of phase cancellation varies from one set of pickups to the next , but you wouldn't want to eliminate it . It's a big part of what makes a Jazz Bass sound the way it does . Putting both pickups on full and then very slightly rolling off the volume of one of the pickups is a great trick to get a bit more mid - focus with plenty of bottom end support from the neck pickup . Having the two pickups adjusted to the appropriate height in relation to each other also affects the degree of perceived mid - scoop .

[iiipopes]

Impedance loading. This is common for almost all passive Jazz basses and derivatives. When both pickups are full on, the impedance drops in half and the output drops slightly. Either roll off one of the pickups to about 8, or install (like I have done) a .01 capacitor between the hot lead of the bridge pickup and its volume control. This will clear up the bass and you won't have the drop when both pickups are full on. The bridge pickup may have slightly less output as a result, but it can be adjusted closer. The EMG active pickups don't have this problem because their output is already buffered low impedance.

[Sharkfinger]

[quote name='iiipopes' timestamp='1374589405' post='2150564']
Impedance loading. This is common for almost all passive Jazz basses and derivatives. When both pickups are full on, the impedance drops in half and the output drops slightly. Either roll off one of the pickups to about 8, or install (like I have done) a .01 capacitor between the hot lead of the bridge pickup and its volume control. This will clear up the bass and you won't have the drop when both pickups are full on. The bridge pickup may have slightly less output as a result, but it can be adjusted closer. The EMG active pickups don't have this problem because their output is already buffered low impedance.
[/quote]
Interesting. I would have thought that putting that cap on the neck pickup would make more sense, as the output will be a bit higher anyway?

You haven't explicitly said so but I take it that also deals with the slight mid scoop?

[Conan]

Both pickups full-on is my favourite sound from a J bass (or equivalent). You can still make it sound good in a band context by judicious use of EQ, but, to be fair, it will never cut through as much as either pickup soloed. Such is life!

[Ghost_Bass]

I once wired a PH bass (i know it's not a jazz) with the '62 stacked pot config. I added a resistor fron the hot wire of each tone knob (in this case would be volume) so that the tone caps won't mess with each other. After doing that there was no significant loss of anything when both pickups were on full.
I allways wondered if such thing could also work in the VVT jazz setup to prevent the kind of thing you're experiencing...

Anyone offering to test it? I currently don't own any J!

[iiipopes]

[quote name='Sharkfinger' timestamp='1374604186' post='2150829']You haven't explicitly said so but I take it that also deals with the slight mid scoop?[/quote] Yes. I'm not a "scooped" kind of player. I play very little music with my bands that needs that tone, so I usually deal with it on the amp instead, or onboard my most recent 5-stringer, an inexpensive 2011 Ibanez model SRA305. In addition to being wired like a Jazz bass, V-V-T, albeit with EMG passive HZ pickups, it also has the Ibby version of the EMG EXB variable scoop control, which is a great unit. Ibby calls it a "Phat II." It raises bass and treble while simultaneously dropping mids at @ 1kHz.

Edited July 24, 2013 by iiipopes