JJ Electronics Amplifier Tube (T-6CA7-JJ-MQ) The new JJ 6CA7 is a more classic version of the EL34 tube. It has a large bottle and big, warm sound. Available in Singles, Matched Pairs or Matched Quads - please select from list. 6CA7 Available in Singles, Apex Matched Pairs or Apex Matched Quads - please select from list.