I just bought this 100W 1975 Fender twin reverb. The original Fender blue label speakers work fine and I really love the sound of this amp. I see theres alot of people that upgrade the speakers and Jensen C12K's seems a popular recommendation.

So how much better are the Jensen upgrades compared to the original factory Fenders?

Can anyone explain how the sound would differ between the two?

Thanks in advance!
I can't answer your question so bump for ya.

My only 2 cents is that I hear the Fender blue lables are actually pretty good and you will retain more resale value if you keep it original. Plus speakers tend to sound better with age.
For a twin, I would whole heartedly reccomend the Weber AlniCO California, It is a direct replacement for vintage fender/JBL Speakers, especially designed for blackface and silverface twin amps: https://taweber.powweb.com/weber/cali12a.htm

If you are set on replacing the speakers, those would definitely be what I would get.
Nah, not gonna bother swapping out the exisiting fender speakers. They work fine and the amp sounds amazing as it is. I'm just more curious as to why these amps are such a popular choice for swapping out the speakers. It causes one to think that the original Fenders are in some way no good.

Even when these amps were rolling off the production line Jensens or JBL's came as standard. I'm just wondering how the sounds differed between them?
I've heard the original speakers are two "relabeled" 50 watt Jensen C12Ns. The C12K is very similar, just rated for twice the wattage.