Hi Henry No you don't need a pre amp Henry ....the link you posted is to the newer Nashville series pickup. That's the type I was referring to as a 'bridge segment' pickup.
In the Wechter Reso I sold you is the Classic series active pickup this one...
http://www.stewmac.com/shop/Electronics ... ickup.htmlThe pre amp is located in the jack plug and powered by a 9 volt battery located in the guitar body. You will need to remove the cone to change the battery. Unless you have left the instrument plugged in for many hours this should not be necessary as I put a new battery in just before I shipped it to you.
Some folks do not like this type of pickup and yes it is a pain removing the cone assembly to change a battery but if set up properly they do give a reasonable sound at low/medium levels.
You may find this link useful the instructions for fitting are on this page.
Hope you get it all sorted out cheers
dave
http://www.fishman.com/product/classic- ... nic-pickup