Prior to this JJ 6CA7 tube being introduced the choice in a 6CA7 tube was NOS or the Electro Harmonics 6CA7EH. JJ has provided another choice and another price point. JJ tubes tend to be well made and this model fits well into the family. Nice construction, good glass, and the base and pins are well assembled. Although this is a replacement for the EL34 tube, the 6CA7 tube looks nothing like a pentode. In fact, an examination reveals what look like the beam forming plates you usually see on a 6L6 power tetrode. I’m not 100% sure of what’s going on in there. The JJ 6CA7 tube looks and sounds like a 6L6 but biases like an EL34. When installed in a 50W Hiwatt head these tubes just roar. It’s a classic sound for beefy rock anthems. The sound is firm and articulate. A number of customers have reported that this 6CA7 tube is darker sounding. Your mileage may vary but I found nothing dark about them at all. Smooth yes, dark, not so much in my testing.