Vintage American.

This is the sound of a Deluxe Reverb, a Tweed Twin, a Princeton with the reverb tank rattling. The era runs from the mid-fifties through to the silverface transition — silverface being the CBS-era redesign, not the blackface cosmetic crossover that trailed it. The unifying voice across those years is a low-mid scoop. That dip is what players are hearing when they call a Fender clean "glassy" or "open": the low-mids step out of the way, the bass rounds out underneath, and the presence region sits in clear air above.

Inside the family, the split is magnetic. The Jensen P-series alnicos — P8R, P10R, P12R, P12N — are the tweed-era voice: looser, more ragged under drive, a midrange that blooms and compresses as you push it. The C-series ceramics that followed — C12N and its siblings — carry the blackface voice: tighter, clearer, firmer at the low end, glassier on top. Same family, two temperaments. Neither is an improvement on the other; they’re the sound of two different decades of Fender amp.