Steve, this is info I found on the reverb tank.
Type 4FB2A1A, Accutronics, Geneva Ill.
4 = Long 2 springs
F = 1475 ohms input impedance
B = 2250 ohms output impedance
2 = 1.75-3 sec decay rate(medium)
A = grounded input, grounded output
1 = no lock
A = open side up.
Is this the right tank for my K150-8?
Concerned about the first "A" part, grounded input grounded output.
Other numbers on the tank are:031-0005-00, 25-75-301 & 23572-0.