I'm pretty sure the Fender Dual Showman with a pair of 15's was one of the early
semi-concert ready bass rigs as far as USA built.
The Ampeg B-15 introduced 1960 was probably the best sounding set-up, but
somewhat under powered for larger venues before large PA systems
came into play.
"Ampeg introduces the B-15 Portaflex, flip-top bass amp in 1960. Tuned and front-ported, with a closed back, the 25 watt 1 x 15" Portaflex sets a new standard for tone, cabinet and speaker efficiency, and convenience in bass amplification. The 25 watt 1 x 12" B-12 follows shortly and by 1963, Ampeg offers the stage-shaking 50 watt 1 x 18" B-18 Portaflex amp."
Just found this Ampeg history link.
Ampeg : History - Milestones
In 1949, the Ampeg Bassamp Company is founded by Everett Hull in New York, after the Michael-Hull company break-up. The first Ampeg Bassamp is the 18 watt 1 x 12" Super 800 model with a rear ventilation port that led to later experiments with sound porting-but then Ampeg breaks new ground in 1951, using a larger speaker, with its 20 watt 1 x 15" Model 815. Throughout the '50s, Ampeg refines its 1 x 15" Bassamp line, upping wattage and control features and offering briefly, the 50 watt 2 x 15" Model 950-C in 1959 and 1960.
Vox Super Beatles had the power but were very unreliable.
Hiwatt 200 - don't know when they were first released.
My first bass amp was a used Sunn 200S around 1969 with a home made
2X15 cab.
You didn't really need so much power for recording, so the real power push
only came after bands needed more power to cover larger venues live.
So really, it looks like you already own the first ultimate bass rig with your
B-18
