The awesome ribbon mic transformer LL2912 by Lundahl Sweden is well known as first decision for many ribbon mic mods. Modification instructions for ribbon mics like the TnC ACM-4 and the R1 MKII can be found online on many blogs and also A/B comparisons but it works with many other microphones which fit to this transformer as well. Because of Lundahl LL2912 is a flying lead version you can handle it easily without circuitboard. Core is the Lundahl proprietary high mu amorphous strip core type.
Author: Don