The U 397 does use a variation of phantom power with a 9V source, whereby the negative source is feeding the device through 2 equal 270 Ohm resistors and the return to the positive source is via ground, unlike the 'normal' phantom, where the positive operating voltage is fed through the isolating resistors, and the negative return is through the ground.
T-power, also known as AB-power is entirely different, in that it does NOT involve the ground (shield) at all, but applies the operating voltage (typically 12 Volt) via one 360 Ohm, or two equal 180 Ohm resistors between the two conductors of a twisted pair delivering the audio as well. The positive audio phase and positive operating voltage are applied to pin 2 of a 3-pin XLR-connector (pin 1 of the 3-pin DIN-connector), while the reference (negative audio and operating voltage) is pin 3 of either XLR- or DIN-connector. The shield carries neither audio, nor any operating current, and is connected to the microphone housing via pin 1 of the 3-pin XLR, or pin 2 of the DIN connector.
Applying the differential 9 to 12V from a T-power supply to a -9V phantom powered U397 will not work and may damage the output section of the microphone. It should be fairly easy to modify the 6-unit T-power supply to -9V phantom power for use with the U397. For details, please contact me separately off this forum.
Best regards, Uwe Sattler Technical Director, SEC