aCM1200 = Apex 460... search for that, there is tons of info.
If I attached it right, the schematic is below. I think I also changed C6 for a panasonic FC or something, but can't say if it made much difference. The mic is OK as is now, but I still need to change the zeners to lower the B+.
hope that helps!
Thanks for posting that.

I already had the APEX460 schematic but besides the Tube & 10uf on the 1200mic... what else is different?
Is there a marked up schematic anywhere?
BTW, about the other mics (Ribbons)
I got some ACM2 & ACM70 mics just for fun & they're both pretty cool. I'm a little lucky that I'm friends with Clarence Kane of ENAC. He lives about 25 minutes from my house & the past few weeks I've been over there doing some hanging. Clarence is so cool & chill, full of knowledge. He's been teaching me how to work on my own mics, cut & corrugate the ribbons, etc...
All my mics have new RCA ribbons installed (by me

) & new transformers. I'm actually trying the Cinemag 1:36 = 9887 right now.
The Lundahl 1:37 works well with them too. I measured the impedance to be aprox 200-300ohms for either mic with the new ribbon & TX.
The original transformers in the ACM70 & ACM2 (fat head) have a 1:52 ratio

- & impedance comes out around 600ohms for BOTH mics (even though the ACM2's specs say it's 200ohm.. WRONG!

) The high ration makes for higher gain but also higher noise & Impedance!!!
The RCA ribbon is 1/10,000 in = 2.52 micron
Not sure what the china ribbons are but seem to be a little thicker... it's very hard to tell & they're probably not consistent.
I'd say anywhere between 1.8 - 2.5 microns with the 1:37 step-up would be a nice improvement. Actually, just re-adjusting the original ribbons & installing the new TX made a HUGH difference. YES, it lost some gain but it's MUCH smoother & Balanced.
Hope some of this info helps someone... I've been very lucky to have other experts share with me.