The CV1660 is a directly heated triode. The prototype was the commercial audio output valve LS7. The old GPO code is POVT82.
The KB/Z identifies this valve as being made to specification K1001 or K1006, the B denotes qualification by a UK authority and the Z identifies the maker as MO Valve Company, Hammersmith.
The filament passes through the control grid six times and the top loops are tensioned by the springs above. As a low power valve the pressed box anode id left bright.
The tension springs have coils and end in hooks. The construction employs a side mounted glass rod to hold the springs.
The top mica with the grid winding visible within.
The classic envelope is 45 mm in diameter, and excluding the B4 base pins is 91 mm tall.
