I have noticed the back plate on my Distillate rattles a little bit on some notes when i play unplugged. Anyone else have this issue? I was thinking of trying to insulate the inside somehow, anyone have any suggestions?

Yes. My Spyder was so resonant that the back control cavity cover plate rattled. I placed some small strips of thin cotton cloth between the cover plate and the wooden edge of the cavity and that stopped the rattle when I replaced the cover and tightened the screws.
 
It took me quite awhile to figure out what was causing the rattle. I originally thought it was a string, or the bridge or a loose pickup screw.
 
These basses are so resonant that everything vibrates, which can sometimes make it challenging to track down the source of a rattle.
 
You might also want to check to make sure the cover plate isn't warped slightly - if it is, it won't make good contact with the edge of the cavity. You'll want to correct this as much as possible prior to doing anything else.

I would also check the ferrite core and battery to see if they might be rattling. To fix just use a bit of foam.  
 
Keith

Thanks guys! Not sure what a ferrite core is though?

It's the grey metal tube that the pickup wires go through - cuts down on RF interference.
 
Graeme

My Distillate's cover will rattle also.
 
I do not over torque the screws as stripping them out could be a real bugger . . .  so when she starts to rattle I will just snug up the screws a tad.
 
 
Thomas, I see you are new here - we really enjoy pictures of others instruments.  You should go here:
http://club.alembicguitars.net/Images/411/419.html?1422414448
And start a thread for your Distillate.
David's suggestion is wise, the cloth would act like a gasket and probably assist with holding the torque of the screws.
 
(Message edited by pauldo on March 31, 2015)

Just make sure the cloth, or other chosen material, is thin, otherwise it will cause the cover to protrude slightly above the surface of the bass (also undesirable).
 
And - Pauldo is correct - take care that you do not over-tighten the screws. Screwed THAT up trying to fix a rattling PRS Custom 24 truss rod cover several years ago - ouch.
 
Ahhh - the price we pay for resonance...

Stash the brass, make yourself a cover from single ply pickguard material, and lose one half a pound off your shoulder.
 
 
 
 
 

Awesome thanks for the help guys. I actually just loosened a few of the screws a bit and presto, problem solved. I think 1 or 2 were just too tight. I didnt notice any ferrite core though, is that something that should be on a 1981 Distillate? I'll try and post pics soon too, but it's this bass : http://club.alembicguitars.net/Images/395/145489.html?1357078537