I recently found an Ampeg B25b cab on craigslist for sale. After talking with the seller I found out it was one of the ones without the impedance switch from 4 to 16 ohms and that it was only 16 ohms. I'm assuming that it has two 8 ohm speakers in it and can be rewired for 4 ohms. Am I assuming correctly? and is this a fairly easy and cheap thing for an amp tech to do? Also I'd be using this with an Ampeg V4 head. Anyone else ever use this setup?