Electro Harmonix 6CA7EH Vaakumtoru

The big-bottle take on the EL34

The 6CA7 is the wide-envelope member of the EL34 family, and Electro-Harmonix describes it exactly that way — a big bottle tetrode. The larger glass and beam-tetrode internal structure shift the character compared with the familiar straight bottle: the low end tends to sit firmer and the overall response a little tighter, while the tube still belongs in amplifiers designed around the EL34 family.

Current production of consistent quality

Electro-Harmonix tubes are new designs built in Russia rather than repackaged old stock, and many amplifier manufacturers fit relabelled Electro-Harmonix tubes in their own products. For an output tube that consistency is practical: replacements behave like the tubes they replace, which keeps bias settings predictable.

Before you fit it

This is a power tube on an octal base with 25 W plate dissipation. Output tubes work as a set, so replace all output positions together and have the amplifier re-biased to its specification. This item is a single tube.