What kind of tubes are these?

[Jakob]

Hey, I found some old radio tubes at a market in NY, but I wonder if these could be used in my Nomad 45w amplifier...

I got

12AT7s
12AV7
12AU7A

12BH7A
12BY7

I also got a 6T8 tube, guess this can't be used. Looks similar to the 12Axx tubes though...

 

[jrkooshman]

http://en.wikipedia.org/wiki/12AX7

ome American variants of the 12AX7:

* 12AD7 (October 10, 1955 - 225mA heater - low hum)
* 12AT7 (May 20, 1947, dual 6AB4, Av = 60)
* 12AU7 (October 18, 1946 dual 6C4, Av = 17-20)
* 12AV7 (February 14, 1950 - dual 6BC4, Av = 37-41)
* 12AX7 (September 15, 1947 - like miniature 6SL7, Av = 100)
* 12AY7 (December 7 1948 - Av = 44, for audio preamp use)
* 12AZ7 (March 2, 1951 - 225mA heater, Av = 60)
* 12DF7 (Av = 100, low microphonics)
* 12DT7 (Av = 100)
* 12U7 (Av = 20, for use in automotive radios on 12-volt plate supply)

 

[stokes]

The AT7,AV7,AU7A, and BH7A all have the same pinout as a 12AX7 and can be subbed in an amp with a 12AX7,but are very different and most likely wont sound as good.