I am looking for accurate plans for Altec 612 (Abby Road Monitors)

I actually did and put something on the forum about that, but a lot of time went by which wasn't real good and business fell off where I will probably quit next year and go fishing..............Will 

OT:

Did you ever find suitable ST70 circuit boards for your rebuilds?

DeKay

Did the ghost of Thiel design these crossovers? I guess simpler isnt always better. 

Some nice pics of a custom made set with 615s and time aligned crossovers on the LA C/L.

Sounds silly, but see if you can reach Alan Parsons through his fan club.  I have a friend who asked a Pink Floyd question and he apparently answered.  I have met AP twice and he is a really down to earth kinda guy.

All the best!

You might try Great Plains Acoustics. If he cant help I bet he will someone that can. 

Interesting info in the linked thread regarding variations (makes sense).

https://www.audioheritage.org/vbulletin/showthread.php?11744-Altec-612-enclosure

DeKay