Let's play name that tube

[mort]

I think it might be an old 12AY7 but I'm not sure. Any help?

[loudthud]

Start with an ohm check from pins 4 and 5 to pin 9. Is pin 9 roughly half the resistance to 4 or 5? Carefully inspect the connections. Do pins 1 and 6 go to the plates? If yes it's probably safe to plug it into a guitar amp to see if it passes a signal. How is the gain?

[mort]

Start with an ohm check from pins 4 and 5 to pin 9. Is pin 9 roughly half the resistance to 4 or 5?Carefully inspect the connections. Do pins 1 and 6 go to the plates? If yes it's probably safe to plug it into a guitar amp to see if it passes a signal. How is the gain?

This tube came out of a working amp, so I knew it was good. I did your checks anyway and all answers are yes. When replacing a 12ax7 in a 5F1, it has less gain. The amp will still break up a bit, but it's a pretty big difference.

[kleuck]

Looks like a Sylvania.

[damus]

Easy!!! Dario Miniwatt ECC82/12AU7 , what do I win????