Unbalanced output across strings - '79 PBass

[bassmanbiff]

This is moved from a previous post in the Basses forum ...

Have a '79 Pbass borrowed from a friend and have mostly worked it over ... adjusted the neck relief, set the action where I like it. This thing is like it's just alive and really speaks with authority...

But the odd thing is that it's tremendously heavy on the bass side. The E string just booms out and it seems to get less intense as one moves across the fretboard. This bass is the only one where I've ever rolled off the bass control on the amp (in this case a MarkBass LMII driving a 15 and a 2x10).

I've tried adjusting the pickup tilt to even out the strings, but it's only helped somewhat and I wonder if it's just a case of mechanical resonance in it.

Any ideas what might be up?

[JTE]

Originally Posted by bassmanbiff

...I wonder if it's just a case of mechanical resonance in it.

Well, that's easy- play it unamplified to see how the INSTRUMENT sounds.

John

[bassmanbiff]

You make it sound so easy

Good suggestion though.

[JHorstmann]

My '62 is just like that. Adjust the pickup height (which you already did) and roll of the bass is pretty much all you can do unless you want to start getting into pickup exchanging. Otherwise getting a simple EQ pedal or something would probably fix it to. I like my P's bassy and I can roll up the bass on my MusicMan HH Stringray so it hasn't posed a huge problem for me. Best of luck!

[walterw]

maybe you haven't adjusted the pickup heights enough?

you would drop the E-A coil a bit, and raise up the D-G coil, even pulling it out and adding a bit of foam rubber underneath if necessary.

both coils should be a little higher as they go in towards the middle two strings, to follow the curve of the fretboard.

the whole idea is to get all 4 strings to have the same volume, so if they don't, you're not done yet.

[bassmanbiff]

That's what I tried to do, but usually fine tune the height based on how the strings actually respond.

As you say, it may be necessary to go a little more severe on the tilt. A spring was put under the pickup ears so they'd rise when the screws are backed off.

[202dy]

Pickup height: 1/8" and 3/32" bass and treble sides respectively. This is a good starting point. It can be fine tuned from there.

If the foam or springs under the pickups are original equipment it is likely that they could stand to be replaced. Label and save the old (existing) hardware in a safe place. Someone in the future will want them.

[Slowgypsy]

Have you considered the strings? What's currently on there now and how old are they? Just a thought... but strings can make a difference.

[bassmanbiff]

Thanks for the suggestions about pickup height .. will check that. Didn't really have an idea what might be typical for a Pbass of this age.

Made a point of putting new strings on it, before working on this issue.

I've been kind of wondering if it might be related to the magnets losing their strength over time ...

The acoustic behaviour suggests it's pretty resonant when the open E is plucked.

Regarding the foam/springs under the pickups. It has the original foam, which now does not uncompress and I didn't really want to remove it since it's not my bass. That's why I added springs under the pickup ears around the mounting screws.

The owner of the bass doesn't seem to mind whatever I do to it (he's a guitar player) and is just glad someone that has an idea how to do anything with it has taken an interest.

[bassmanbiff]

In reviewing the message about the pickup height .. if that's the measurement from string to pickup it strikes me as a little close.

If it's the exposure above the pickguard, then I'm about 3/32 on the E string and 8/32nd at the A string.

If from the string to the top of the pickup, E is 7/32 and A is 5/32.

[202dy]

Originally Posted by bassmanbiff

In reviewing the message about the pickup height .. if that's the measurement from string to pickup it strikes me as a little close.

If it's the exposure above the pickguard, then I'm about 3/32 on the E string and 8/32nd at the A string.

If from the string to the top of the pickup, E is 7/32 and A is 5/32.

The measurement is from the top of the pole piece to the bottom of the string. Sorry for the omission.

[walterw]

Originally Posted by bassmanbiff

Regarding the foam/springs under the pickups. It has the original foam, which now does not uncompress and I didn't really want to remove it since it's not my bass. That's why I added springs under the pickup ears around the mounting screws.

the only problem with that is the pickups are now hanging unsupported off the insides of the covers.

i would just add a layer of foam over the old stuff, so the pickups were pushed up against the insides of the covers and could be adjusted without getting loose.

[bassmanbiff]

Actually this particular one has the pickups mounted to the body with long screws, so they're not suspended from the pickguard.

It looks like getting radical with the pickup tilt has done the job. I appreciate all the suggestions.

[walterw]

Originally Posted by walterw

the only problem with that is the pickups are now hanging unsupported off the insides of the covers.

Originally Posted by bassmanbiff

Actually this particular one has the pickups mounted to the body with long screws, so they're not suspended from the pickguard.

i think you misunderstand. the pickups themselves just sort of slide into the plastic covers, and can fall out if not supported from underneath.

nothing to do with any pickguard.

[JTE]

If you still have old mousepads, they make great foam for putting under Fender pickups to elevate them.

John

[bassmanbiff]

Ahh, ok got it regarding the pickup covers not providing sufficient support by themselves ... mouse pads sound like a good idea, too