Electro-Harmonix 6CA7EH Power Vacuum Tube (Matched)

Need matched power tubes? Don't worry! Price includes matching in any quantity you need for no extra charge. Need a matched pair? Just order "2" tubes. For a matched quad order "4" tubes. Matched sextets and octets are available as well.

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The Electro Harmonix 6CA7-EH power vacuum tube has been available for nearly 20 years. This power tube is a tribute to the legendary USA made Sylvania/Philips 6CA7 tube, with its fat-bottle and sturdy plate.

This 6CA7 vacuum tube can be used in nearly any EL34 tube amplifier, and is considered a drop-in replacement. However, it does have different bias voltage requirements than most EL34 vacuum tubes. We find often an increase of about 30-50% more bias voltage is needed to operate the 6CA7 appropriately. If you're not sure if your tube amplifier is compatible check with us or a technician you trust. If you're amp's stock bias range can't dial them in, usually a simple resistor change is all that's needed.

The history of the 6CA7 is quite interesting. Eric Barbour's article (Senior Editor, VTV Magazine 2001) has a good summary of how it began. In the very late 1960's, Sylvania "took a 6550 structure and changed the grids, so the tube biased like an EL34." Simply, Sylvania wanted something to compete with the popular British Mullard EL34 at that time. So in technical terms it is actually a tetrode and does have more of a 6550 tube sound characteristic because of it. Normal EL34 tube types are pentodes. Eric mentions the reason for why EL34 sound so different from 6550, 6L6, KT77, etc is because at the time they were considered a lower cost option with a softer vacuum than the 6CA7 and 6550 tubes. This leads to them being easier to drive, and having smoother overdrive, than 6L6 and 6550, especially when really pushing them in a tube guitar amp.

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