New-Old-Stock (NOS) tube 12AB5 - Tetrode, Beam Power The 12AB6 is a beam power tube of the 9-pin miniature type designed for use as the output amplifier in automobile radio receivers operating from a 12-volt storage battery. The 12AB5 can provide high power output because of its high power sensitivity and high efficiency. Design features of the 12AB5 include a large plate structure to allow for greater heat dissipation, a heater specially processed to withstand the severe operating conditions encountered during battery charging and discharging, and double base-pin connections for grid No. 1 and grid No. 2 to provide for cooler grid operation and greater flexibility of circuit connection.