Twang Factor 10
Tele-Meister
I have a Champ with a blown speaker. What ohm is it? What is the best replacement? GO!
Weber Sig, as noted, is *extremely* popular in Champs, dead cheap, not too refined -- keeps the Champ vibe. If you want a little more sophistication, their 8A125s are great, but see their notes -- you may need their narrow basket.
I have a Jupiter in a Milkman Half Pint and it's quite possibly the best speaker I've heard. Of course it's a slightly different amp.. But it's close enough that I'd definitely recommend it for a Vibro Champ!I haven't tried it yet, but the replacement speaker from Jupiter is supposed to be fantastic.