Another tube question

["adams, john" <adams_john@xxxxxxx>]

I just received today a 12dw7 tube.  This tube has two dissimilar triodes in
it.  One has a gain of 100 (same as 12ax7) and the other has a gain of 20
(same as 12au7).  My amp ( a Silvertone 1472 ) has two channels, one for mic
and one for instruments.  The low power side is going to be on the
instruments side, not the mic side.  Now I can either plug my mic into the
instrument jack, or re-wire the amp.   I use the other channel for guitar,
so I don't want to reduce the gain on that channel. 

My question is, does anyone know if there is a tube that has the low power
side on the opposite half of the tube?

Thanks

John

http://www1.korksoft.com/~schem/bargainbin/silvertone1472.pdf