The EL506 is an audio output pentode. In single ended use the typical output would be 10 Watts at 13% total distortion, but a push-pull pair was rated at up to 40 Watts output by Brimar.
The EL506 was a development of the RCA 7868 and is pin compatible with it.
Push pull pairs were used in 30 Watt amplifiers and the electrode dimensions suggest a 25 to 30 Watt anode dissipation. The VA-12 amplifier designed by Thorn-AEI is described in the attached PDF file.
The gaps in the end wall of the anode reveal the beam plates and so although regarded as a pentode the construction is not.
The anode sections are stitched and the flanges so formed are in the centre of the working face for greatest cooling effect.
The circuit of the VA-12 amplifier from 1967. The VA-12 was designed for both HI-FI and Guitar use. Thanks to Terry Bateman for sending the Application report No. L.96 as PDF.
The wide glass tube envelope is 28 mm in diameter and, excluding the B9D base pins, is 71 mm tall. Thanks to John Rumens for donating this valve.
Reference: 1040. Type EL506 was first introduced in 1966. See also1966 adverts.
