The directly heated battery valve DEH610 was used as an anode bend detector in broadcast receivers. The DEL610, used for AF stages, was a lower gain version of the DEH610.
The DEH610 has barium-coated filaments made using the Azide process.
The gettering obscures the inner structure. The etched M of the Marconi logo can be seen on the right.
The box anode lies horizontally in the envelope. More of the Marconi Name and BVA logo can be seen.
The balloon envelope is 44 mm in diameter and, excluding the B4 base pins, is 84 mm tall.
Reference: Data. Type DEH610 was first introduced in 1927. See also1927 adverts.
