The Powertechnik Tubelife-249 is a 19" PSU supplying two tube mics with AC701. It can supply many Neumann models like M49, M50, KM53, KM54, KM56, KM253, KM254, M249, M250, KM256, M269, KM63, KM64, KM65 or also Shoeps M221b.
All voltages are electronically stabilized and filtered generously in order to optimize the residual noise level. The schematic design guarantees low noise and also stable output voltages. The good qualities of the predecessor model Tubelife-2 were improved further.
We replaced the unshielded flat transformer of the Tubelife-2 through a shielded ring transformer with static shield between primary and secondary and a magnetic shield of transformer sheet metal.
This PSU is suitable also for microphone models, that are very sensitively for noise and humming of the PSU, because it have a internal connection between heating and cathode.
In the regulation of heating voltage a soft start circuit avoids the cold electric push and thus extends the life of the tubes of microphones. The full voltage will be reached after approximately one second.
At the rear side of PSU the Inputs as 6-pin XLR female sockets are built-in. The Outputs are standard 3-pin XLR male sockets. The symmetrical audio voltages of the microphones are directly connected to the XLR Outs of the PSU.
At the potentiometers on the front side can be selected the polarization between omni, cardioid and figure-eight without steps. The selection is made through the polarization voltages at the pins 6 of Input connectors. If the used mics are not switchable, the pots don't have any influence of their characteristics, because the pins 6 inside the microphones are not connected.
