The ER30 valve head may have been introduced with the ER15 in 1964/65, or somewhat later. A 30W push-pull valve amplifier, it had 2 channels each with 2 inputs, treble-boost slide switches, and bass, treble & volume controls. Valves - 4 x El84, 3 x ECC83 .
Usually labelled "Control ER30 : Controlled Power Amplifier". Recommended speaker cabinets were the Super Bass 15 or Dual 12. It stayed in the catalogue for several years, but was eventually superseded by larger heads.