I was fortunate to come across a 1971 Ludwig chrome over brass super sensitive a few months ago. I've read a few threads about these drums, and wanted to share some photos and a bit of information I found online.
I originally thought it was your standard Ludalloy SS, and was just happy to find one without any pitting or flaking. It wasn't until I got it home that I noticed the B stamped behind the muffler knob, the cut-down B/O badge, etc. and realized it was actually a brass shell (I'm fairly new to vintage drum collecting and didn't really know what to look for right off the bat). Someone had also flaked a small piece of chrome off inside the shell at some point to show the brass beneath.
The label inside indicates a manufacture date of November 16, 1971. I've come across a couple of other COBs online that were also made in November / December of '71. The label reads Model No. 416, which I understand is the same number used to designate Black Beauty snares.
A few people have said that some of these COB drums were made specifically for Hollywood Pro Drums. I visited their Facebook page, and came across a photo (attached) and the following caption:
“Behind Maurie are the famous Brass Ludwig chrome snare drums that Bob made Bill Ludwig make us after *****ing about not making the brass shells since 64’…only 100 made in 5 and 6.5 x 14 ..they have a “B” under the tone control with the blue and olive badges…still see a few every now and then….. circa 1972”
In any case, I know questions about early 70s COBs come up from time to time - thought this might be of interest.