[BluesJam]

Typically, I like to put foam under my FS1’s and my Super Distortion Pickups to prevent feedback .  Today, I played a guitar that don’t normally use.  The FS1, screech to no end, the bad high squealing noise.  I wired the pickups to the jack and everything was OK.  I trouble shooter it to the foam under the pickup.  Once I removed the foam, things settled down.  I thought it was unusual.  I’m also going to order compression tubing.  Replacing springs with compression tubing may be a good idea, too.

[buddroyce]

I do find that even though foam can dampen signal, it can also trap signals as well. (I could be wrong, it's just my perception).

I've always preferred compression tubing over springs whenever I can, but that's just me.

[darkbluemurder]

Very unusual - never experienced that.

Cheers Stephan

[DarthPhineas]

The only benefit Ive ever gotten from foam under a pickup is keeping/making the humbucker coils level (or the same distance from the strings).

[BluesJam]

The pickups sound a bit different without the foam.  I think the foam affects the magnetic field.  The guitar squealed bad.  I put my hand over the pickup, with the strings muted and it squealed.  Took the foam out, and no more squealing.  Very strange.  I heard compression tubing rots over time, do you have any recommendations for material types?

Thanks!

[DarthPhineas]

I think the foam affects the magnetic field.

Be interesting to find out where you came across foam with magnetic properties. That just might be a first.

[HarlowTheFish]

The pickups sound a bit different without the foam.  I think the foam affects the magnetic field.  The guitar squealed bad.  I put my hand over the pickup, with the strings muted and it squealed.  Took the foam out, and no more squealing.  Very strange.  I heard compression tubing rots over time, do you have any recommendations for material types?

Thanks!

That's interesting. If your foam was compressing or aging weirdly it might have been causing some weird microphonics from physically messing with the pickup. I like the foam that comes in pickup boxes and surgical tubing (you need to get the tiny stuff though) because those tend to last a good while.

[BluesJam]

In my guitar, I notice that the spring makes contact with the sides of the FS1.  I’m not sure if that’s an issue, but the guitar is not microphonic anymore.  After this issue, I took the foam out of all my guitars.  TY’