Dating a twin
The image of the Twin-Amp in the 1960 Fender Catalog has been the subject of considerable scrutiny.The re-emergence of the Twin-Amp in mid 1960 revealed a new aesthetic design that would become prominent among Fender's top of the line amplifiers, with the exception of the Vibrasonic-Amp.Fender's 1963 product flyer featured a flat logo, black Tolex amp, while their 1963 full-line catalog showed a raised logo amp on the cover, both with a grey Saran grill.The first production Twin Reverb models used an unusual 7355 power tube (weaker cousin to the 6L6) as with their concurrent smooth blonde, blackface Fender Showman amplifier.The Fender Twin Reverb is considered a standard model for players seeking a clean sound, and it is especially known for the quality of its built-in spring reverb.
Today, the famous 5F8 series Fender Twin amps with their warmth of tone and rich rock & roll harmonic edge, command the highest price of any Fender amp ever built!
The final 5F8-A Twin-Amp version released in 1958 and produced into early 1960, had become the crowning achievement of Fender fifties amplification.
The 5F series Twin utilized the finest heavy duty Concert Series Jensen P12-N Alnico V blue-dome loudspeakers (conservatively rated in 1957 at only 18 watts apiece).
It was modified in 1957 for more volume, switching to four 5881 power tubes with the more efficient long-tailed pair phase inverter for a power increase to 80W.
This "hi-powered," tweed-covered design continued into early 1960, after the other Professional Series of Fender amplifiers had made the transition to the modern brownface design.