Are the KTM and the KM74 the same mic? I know the KTM was Neumann's first solid state mic and came out before the KM74, but they look like the exact same mic. Was the KM74 just a renamed KTM? Both are transformerless T Powered (modulation lead powering) cardoids with the same unusual "acoustic phase shift" head grills not used on any other Neumann mic (still not sure what the purpose of those were). Both use the capsule from the KM64. The brouchures on your website for each mic (KTM has date 2/1966 and KM74 has date 9/1966) appear to be almost identical. So do the specs for each mic. I have only seen photos of the KTM, but I own a pair of KM74's that I have used for about a decade now (with a power supply made by Peter Drefahl) and they are absolutely great, top shelf, workhorse small diaphram studio mics. Their speed, clarity and dead quiet operation really shine on delicate acoustic sources like shakers and hand cymbals. For best results, I would encourage anyone using those mics to invest in a quality power supply.
I have become a huge fan of the T Power KM74 and U77 mics that your company made in the late 1960's - early 1970's. They are among my favorite Neumann products. I know modulation lead powering had some practical issues, but those 2 mics sure sounded great and are among the best solid state mics ever made.