Thank you all for your helpful and thoughtful responses. I will follow all this advice. I do not want to just plug it in here and possibly destroy this costly preamp.
It was purchased in the UK in the late 80s. I am now in America, but I am reluctant to try it as the power supply box has no markings of any kind and the documentation says nothing about the voltage requirements.
I'm a bit confused with my preamp I recently purchased. What line voltages can I use on a Musical Fidelity MVX Preamplifier? The manual that came with the preamp does not specify if I can use 120v AC. I currently live in America using 120v; can I use the power supply for the mvx on United States...