Very high pitched feedback! Urgent help needed.

[Prime_BASS]

So new bass build with some old parts into a new body. Old electrics were fine, a nice single volume to Jack job from kIogon, and using a brand new pickup.

I was getting the loudest highest pitched feedback I've ever had!
Things I've done that has helped;
Checked all the copper shielding.
Removed springs from pickup height screws.
Lowered pickups.
Turned treble down.

Now I use a boat load of drive which I know will make it worse but not sure what else I can do.
It didn't do this before hand and it's definitely the bass that's causing it.

[ikay]

Could it be a microphonic pickup?

[Guest bassman7755]

[quote name='ikay' timestamp='1464509188' post='3059865']
Could it be a microphonic pickup?
[/quote]

That would be by guess, magnet or coil vibration probably (assuming the pickup itself is solidly mounted).

I'm guessing the pickup isnt a wax potted one.

[Prime_BASS]

It's a dimarzio model P. Previous bass had the same model in and never did it.

I'll try the old pickup to see if it's that.

Definitely something vibrating though as it gets interrupted when the D and G strings move

[paul_5]

it's not an impedance issue, is it?