Help identifying tube

[mswanson65]

Hi All,
I was hoping to get some help identifying this tube (see pics). All I can make out is a faint “A5”. My guess is that it is a 6A5. Any thoughts greatly appreciated!

 

[maxhifi]

I may be off but that looks seriously like a 6B4G

 

[zackthedog]

Yes, that's what it looks like. Check the filament wiring at the bottom of the plates. If there are tiny round sleeves on them, then it's a 6A5.

 

[Tom Bavis]

Try breathing on the tube number - see if any more shows up.

Yes, 6B4 has exposed heater wires, 6A5 has indirect heating (cathode sleeve). Cathode is connected heater center-tap on pin 8. http://vinylsavor.blogspot.com/2019/12/tube-of-month-6a5.html

 

[Lavane]

Try breathing on the tube number - see if any more shows up.

Yes, 6B4 has exposed heater wires, 6A5 has indirect heating (cathode sleeve). Cathode is connected heater center-tap on pin 8. http://vinylsavor.blogspot.com/2019/12/tube-of-month-6a5.html

If that doesn't work, put it in the freezer. Once it gets good and cold, take it out. The condensation may reveal the number.

 

[mswanson65]

Thanks for the tips! Enjoy the weekend!

 

[gadget73]

If you want to know if its valuable, carry it around while walking on a concrete floor. If you drop it and it breaks it was worth something. Otherwise its some boring radio tube that nobody wants.