It most closely resembles the one Triode Electronics advertises. The tech that answered my query said they never used that color board unless it was a very long time ago.
It uses a 12au7 tube in the center position and two ef86 tubes to the sides.
There are no letters or numbers visible; top or bottom.
Whatever it is, it sounds good. I replaced the center Mullard 12au7 with Cifte/Mazda and am not looking back (hope they work as well in my SP-12
Last edited by fswidecki on Wed Apr 13, 2011 8:56 am; edited 3 times in total (Reason for editing : still trying to add image)