There are three significant differences between the ULS and the Blue Line that have relevancy to stealthing, especially if the choice stands between buying food or getting a mic set up.
A) Unlike the ULS caps, the Blue Line capsules are electret
B) The Blue Line has sufficient performance in the integral active buffer to allow direct wiring ..
C) If one stares at a BL capsule for a while the bayonett connector sure starts to look like a cable exit port...
I.e all your really need are a pair of capsules, some 10 feet of strong starquadcable, a 9 Volts battery box and some epoxy. Now granted, the resale value might be slight :-) but it's a rugged setup tolerant of both humidity and high sound pressure levels.
hold the train!!!
it seems you are saying that you can make a set of steath cables for the Blue Line caps, but what about the bodies?
the extension cables I have seen for the 300 series still need the bodies in the line, so does this mean I could run the cables as stated above with a (v power supply right into a pre-amp?
this I might just try!
If you look at the CK91 and compare it to other modular caps (like CK61, M21, Mk4 or Nakamichi CP capsules...), you'll notice that the Blue Line capsule is mechanically very "complete": Solid body, vents and slots, fully enclosed rear and a rear exit port! Mechanical challenges are often _the_ major obstacle in making active heads. With the CK91 on the other hand, most of the mechanical stuff is there already. The "tailpipe" even acts as exit port for the new cable and supports strain relief etc.
Some electronics work is required on the inside the CK91 and a cable must be
permanently attached. Ooops there went the modular aspect out the window. Seen as a whole this modification is rather delicate but straighforward. It is _not_ easily reversed.
The cable added to the CK91 must be terminated in a connector or hardwired into a box. l
The alternative to all of the above is to get the AKG BL extension cable. It's a cable with connectors in both ends.
What do you do at the mic body side?
Irrespective of if you run a "custom permanently attached cable solution" as above, or run the stock AKG BL extension cables, it is possible to remove the bodies. Their essential functions though must be replaced by some other device. Their "non-essential function we don't need (converting phantom power to 9 Volts, ++).
At a minimum a box containing a 6 to 9 Volts battery is needed. The savings so far in bulk and weight depend strongly on the connectors used but it is a way to get a fairly stealthy setup with just the capsules. Sonically there is no reason to think it is in any way inferior to running 300.
One can visualize putting more functionality inside the "CK9x batterybox". A quick search on the net for keywords "CK91" and "ECMS" will likely give some hits to a recording or two made with such a system.