12AX7A preamp tubes - ribbed vs smooth plate

@jond 

You got lots of cool stuff. Maybe you have too many tubes in boxes. Why you have so many tubes?

4 12AT7 tubes. no clue what they do Beyond rectify. I know rectify transforms AC to DC and why you need four tubes to do that, dunno.

Hey emergingsoul I very well have too many tubes in or out of boxes that said the 12AT7 tube is not a rectifier tube.

"4 12AT7 tubes. no clue what they do Beyond rectify"

Your amp is SS rectified, not tubed.

2nd gain stage/phase splitter? Just guessing.

It's a mono block amplifier with 8 KT 88 and 6 small tubes (  4 rectifier, 2 preamp).

I assume the "2 preamp" tubes are the amps input tubes or driver tubes?

. . . ohhh, so they are MC9011s? I just did a cursory read on them--interesting amps.  Anyway, Mac is calling the two 12AX7s the signal tubes for the amp.  Which is not what I would call a "preamp tube"  (I would call a preamp tube a tube in the preamp) but I guess it doesn't matter what you call it.

I wonder what the 12AT7s are for?  Inputs or drivers into the ss section?