M-11 12AX7/12AU7 Conundrum

[(lmark)]

Hi!

My M-11 (1957?) seems to call for a 12au7 in V1 and a 12ax7 in V2 (stamped on chassis); however it sounds horrible this way (way too much distortion). If I put the 12au7 in V2, however, the amp kills, and is still loud. Is there any possibility the chassis was stamped wrong?

All caps and cap can have been replaced with new, as have all suspect resistors.

Thanks,

Mark

[(tracy)]

The chassis must've been mismarked. One of my M11's calls for the 12AX7 first, 12AU7 2nd. A later M11 shows 12AX7 in both positions. I gig with the 2/12AX7 version. It's a bit louder.

[(lmark)]

This is a super-old thread that I am waking, but I want to note something that I discovered today. Put the 12ax7 in V1 and the 12au7 in v2, just like it's labeled. Plug your Tele into the instrument jack. Turn on power and leave tone maxed to treble. Max the MIC volume (not the INSTRUMENT volume). Now slowly bring the INSTRUMENT volume to 12 oclock or so--maybe 2 o'clock. How do you like THAT tone? Turn off amp and reverse the two tubes. Even BETTER? YAH! Spread the word. LMark

P.S. Doesn't it sound like the AB763 circuit?