Cabinet Impedance?

[el nino]

Hello to all...

i've been lurking here for some time now and this is my first post,so i hope it's in the right section.

Anyway i have a Marshall JMP Super lead 100w that i just got back from my tech who rewired it to run on 50w and he added a master and some preamp thing thats fantastic (i'm not that good with the tech stuff).he put (on the back panel) that switch for the 8ohms 16ohms and 32ohms and said to always run the head for example on 16ohms (as i did) and the cabinet (i have a old marshall with 16ohms greenbacks) on 16ohms.

but heres the problem: the cabinet was rewired for 4ohms,so before i plugged in i had a guy (who did this kind of wiring just with car stereos) rewired the cabinet to run on 16ohms but when he used the ohmmeter some speakers were running at 14ohms (two of them) and the other two on 10ohms and 11ohms!

he said thats normal but like i said i'm not good with this tech stuff so i wanted to ask you guys is this normal?
i mean i just got back the amp and i'm affraid to plug it in!(i played it for a half an hour after he rewired it on 16ohms and it worked INCREDIBLE)
if it's not normal whats the possible damage that could happen to an amp?

[SatelliteAmps]

That is normal. Impedance and resistance are two different measurements. When testing the impedance of a speaker with a resistance measurement, the results will be a bit different. A 16 ohm speaker will usually read between 12-14 ohms.

[donnyjaguar]

Agreed with Satellite. I'm a big fan of running the higher impedances when its an option too. You get better coupling efficiency in the output transformer because more of the secondary winding is used. Others will argue that there's no benefit to using 16Ω over 8Ω, but the above is not a point of conjecture. :)