Behringer PS400

Just recently bought the PS400 for supplying phantom voltage to various condensor microphones. In brief: rugid built, however not meeting decent electrical specifications.
- Output voltage (unloaded) equals 12V in 12V-mode, but only 31V in 48V-mode, i.e. much too low! A short check of the internal electronic circuits shows a multi-diode trippler, thus limiting the output to 3x the input voltage, i.e. 36V max. It never will/can reach 48V, as claimed!
- The output voltage STRONGLY depends on microphone current drawing! E.g. in 12V-mode the voltage drops from its unloaded 12.0V to 10.4V (at 5 mA) and 8.5V (at 10mA).
But much more serious in 48V-mode: from 31V (unl.) to 22V (at 0.7 mA) and 12.5V (at 2 mA)! Note that common microphones typ. require 2-5 mA at 48V!
- Noise level is OK, both at 12V (adapter) as well as 9V (battery); at 9V unloaded output voltage is just 9V or 25V (select switch 12V- or 48V-mode).
Fazit: at "48V" setting the unit can not be used. Likely many people will be affected by this deficit, without knowing.