What is a 7247?

[LooseChange]

Looks like a 12AX7. Same pin out too.

[kagliostro]

is not  flour of my bag

12DW7, 7247, ECC832
This is a very useful tube for a lot of applications, with one half of a 12AX7 and one half of a 12AU7 in the same envelope. JJ is currently making a version as the ECC832, and also offers a version with the sections reversed. It has no officially recognized international designation, but JJ calls it an "ECC823." I think it might be VERY interesting to harpers who want a lower gain tube in the first stage of an amp but don't need to drop two stages to such low gain as a 12AU7's. I'm sure you can think of many other situations where this combo would be very useful, such as a reverb drive and recovery tube.

 Here is the JJ spec sheet for their version(s) of this tube: http://www.jj-electronic.sk/pdf/ECC%20832.pdf

that is interesting

Kagliostro

[VMS]

1/2 12AU7 + 1/2 12AX7

[LooseChange]

Aha... So it is a 12DW7

[DummyLoad]

Aha... So it is a 12DW7

yes.     

[HotBluePlates]

And since the euro-designation of a 12AX7 is ECC83, and for the 12AU7 is ECC82, the euro-designation of the 12DW7/7247 is ECC832 (one of each). As noted in the other quote, some companies may mix that up to ECC823.