21-CT-55 has a new home

[cbenham]

Originally Posted by miniman82

Wow, outstanding work!

Looks like they are pretty close, for the most part. I'd bet the later tubes are farther apart than the early ones, have you tested any of them?

Here are the spectrum charts for the 15GP22 and a rare earth Mitsubishi tube at the ETF Museum. Please note that the vertical scale for the 15GP22 is different than that of the 21AXP22 and the rare earth tube. That's why it appears to be very low when in fact it is close to the 21AXP22.