12BH7 bias tube replacement with 12au7

[Siemens EL34]

Hey Guys..could you please advise me if I can substitute a 12BH7 with a 12AU7 in my Magnecord bias circuit? The attachment schematic is for the model P63 but mine a P70 has a 12BH7 ( the rest is pretty much identical). I am not sure why they used a different tube. Thanks for your help!

[sluckey]

I think so. I'd try it. Ain't gonna hurt anything.