I found the results rather fascinating and was rather disheartened by them. I have had over 33 years experience working with Neumann U87s. You indicated you had moved it further away due to its hotter output when used with your five dollar preamplifier. Obviously further away to the point of no proximity effect and/or, it sounded like it was in Omni mode?
Either way, the worst sounding example of a U87, I ever heard. I also puzzled over the fact that you did not use the -10 dB pad switch and/or adjust the gain of the five dollar preamplifier (I know you and indicated it was the design of fixed gain but)?
Of course that may also have led to a slight rise in noise, which I believe would have made for a better comparison, so I'm not really impressed with this cute little deceptive comparison, which I did not find much validity in. I will tell you however, that doing a lot of narrative recording and commercials in our studios, we wanted to find a close match for narrative use.
I found your link within a posting on recording.org, of which I am a contributor of since I have had more years in the broadcasting/recording business than my experience spent with the U87 (not to mention my 3 major award nominations), and probably the only person and American to turn down a maintenance job offering from Sir George Martin, 25 years ago when I was first employed by NBC radio/television network. Yup, I'm an idiot.
Ms. Remy Ann David