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Hi, adrian. Welcome to TalkBass.
My first inclination is to direct you to your nearest Fender Authorized Service Center. Their diagnosis of
why the speaker ripped may be worth the price alone! They are also the
only source for the exact same OEM speaker. Otherwise, you may need
2 new speakers for proper balance, plus some port retuning to keep from throwing off all the different modeling voices. It may cost a bit, eating into your "crazy deal", but I truly believe it's really the best route to get a good, properly working Stage 800.
I cordially invite you to ask this question in
The Fender Rumble Club and it's sub-thread
Fender Rumble LT25, Studio 40 & Stage 800 for any other ideas. Post a photo in
the Rumble Club and you can join up for free. There's also several speaker replacement threads listed in
the Speaker Replacements section of the
Rumble Club Wiki page, linked in my signature, that you can browse to see the various technicalities that go into it.
The Stage is a great amp! I have its little brother, the Studio 40 with the exact same software, and love the various voices it has. I'd hate to see an aftermarket speaker mess up those sweet amps, cabs and effects tones designed for the OEM speakers. I also have a nearly 6 year old Rumble 500 combo that's never had a moment of any problems. Good, reliable amps. Which begs the question, how did that speaker get ripped?
Good luck. Don't be a stranger.
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