Hey Abyss,
This is OT...but yeah I love the sound of those things. Vintech made some interesting mods to the classic units. We have the AMS 1081R pres and 1073 DPA's. I recently got a great deal on an 8816 as well and it's great. Love the out of the box summing...those trannies just do something to the signal. Learning from a recent project we're trying to figure out a good chain that puts some overload protection before the 192's....as well as a good chain for male vocals...ours sucks right now...u87/c12/km184 and those 1073's just aren't cutting it. Maybe we should hop on the tube bandwagon? Thinking about the LA-610 or Summit's new Everest. I've heard great things about Brent Averill's stuff. Do you have experience with API? It's still not quite clear to me where they fall exactly, but if the Waves emulations are any indication, they should be pretty awesome. 
Gerard, Good to hear from you! Sorry to hear that you are having trouble with your vocal chain. I never got off the tube band wagon and love mixing ss and tube on any given day. Are you trying to get more "oomph" from your signal? A U87 is a pretty big sounding mic as it is so using a tube based mic pre and rounding off the signal with the 1073 should sound pretty good. What pre are you using with it? I am a big fan of UA equipment and if you need to try some models out for a bit of flavor, try the LA-610 and maybe an Avalon 737 to give your vocals more presence and girth. If you are using a solid state pre, try running a tube based opto compressor/ limiter after your chain to tame transients and give the vox a nice sheen to it before going to disk. One of my first go to chains involve either a Tube Tech EQ or a Manley SLAM! before going to disk. If you are thinking about Summit's stuff, also check out A-Designs, SPL and Daking - they make top notch pres that might give you what you need.
I do have some API EQs and pres in a lunchbox format and they are great. Soundwise, they are a more contemporary take on the classic Neve/Putnam sound but cleaner and more applicable to what you would hear from Top 40 stuff nowadays. Ditto for Brent Avril pres. Thing is, a lot of tube pres will color your sound from the getgo which may be good if you are going for that vibe in the first place but for recording really pristine and chimey vocals, I prefer using SS pres like API/BE to bring more attack and dynamic track texture to the forefront of my mixes, especially when I am dealing with really busy and aggressive guitar work. The Waves emulations are very good and they do come very close to the API versions.
