Tube construction is quite rugged with very thick glass that’s formed into the typical “fat bottle” construction that I’ve come to expect. It’s quite attractive with the gold pins and very nice gold screening on the bottle.
Structurally this tube is familiar to the eye with the wide ribbed plate design, rounded bottle top and a single round getter with dual support rods. Nothing fragile about this tube. The pins are medium thickness and gold plated to prevent oxidization. Alignment of the internal elements, pin straightness and alignment of the internal plate structure are excellent. It looks like they put a little more care into the construction.
Sonically I find these amplifier tubes to have a lot of punch. More gain than a JJ ECC83S and less gain than a Shuguang 12AX7. Noise is extremely low and microphonics are almost non-existent. I attribute that to the overall build quality. The high end on these tubes may be described as silky. Lots of definition and sparkle without a hint of harshness. The bottom end is not as pronounced as I had expected. Not an issue in a guitar amp and they certainly worked well in my tube pre-amp.
This tube should work well in all applications due to its excellent construction and balanced sonic profile.