EL37, CV586, 5881 OUTPUT PENTODE, OCTAL

The EL37 audio output valve is of pentode configuration and is Mullard’s answer to the mighty KT66 beam tetrode. These meaty beasts could deliver up to 70 Watts at 2.5% distortion when used in push-pull.

Developed from the earlier EL31 and rerated to have higher anode dissipation, the EL37 in characterised by having a massive mutual conductance when compared against its contemporaries. Indeed, 11.0 mA/V is almost twice the value of that shown by the KT66 or the 6L6.

Introduced in 1946, the EL37 was superseded by the introduction of the EL34 some 8 years later, praised for their scarcity, their exceptional sound and ease of driving they are keenly sought for audio amplifier and guitar amplifier applications today,