12V driver tubes for Engineer's Amp?

[bst]

I've started consolidating the parts needed to build Pete Millett's "Engineer's Amplifier". The board and top plate are on order, and I'm digging through my (haphazardly-organized) boxes and bins for iron and passive components.

I discovered eighteen NOS 12JN6 pentodes, which I'd like to use for the output stage. However, I see that there is no 12-volt version of the 6CB6 input/driver tube.

Has anyone used an alternate driver tube (such as a 6AU6) which has a 12-volt variant? Or, has anyone assembled a version of this amp with all 12-volt- filament tubes?

I'd like to avoid two filament supplies, or purchasing a bunch of 6-volt output tubes to test and match.

Thanks for your help.

 

[Tubelab_com]

I ran several different driver tubes through my amp before settling on the 6GU5 (yeah I know it's not a pentode). I did try the 6AU6 and I don't remember it not working. In fact most everything I stuffed into the amp worked. The 6GU5's probably made the cut because I had a bunch of NOS tubes that seemed to be well matched. Most of my 6CB6's and 6AU6's are well used and of questionable quality.

With good matched input tubes and output tubes the distortion will nearly vanish. I have not yet determined exactly what needs to be matched however. I have a bunch of 6JH5's and 6GU5's and I just swapped away until I got good readings. further testing will resume when I finish some other projects.

 

[Tom Bavis]

You COULD wire two 6CB6 heaters in series... though that will require a trace cut or two. 12AU6 is the only common one I can think of... 12AW6 is another possibility.