The F605 is a high performance professional headphone amplifier, offering an effective headphone volume control for live or studio applications in combination with a Fredenstein Bento rack. The Bento racks provide two inputs per slot so stereo modules are possible.
5 toggle switches to provide convenient monitor modes. The top switch simply swaps Left and Right. The next two toggles select Left or Right and present them as mono to the phones. We often use these to compare two mono sources. The bottom two switches simply reverse the polarity (phase) of each of the outputs. These switches are most useful for vocalists, where there may be some phase change between the voice heard by bone conduction and the entire recording path of microphone, pre-amp, processing and possibly converters.
The F605 features balanced inputs, extended signal manipulation and a low output impedance to connect headphones from 20 Ohms to 600 Ohms. It is an unusual module compared to typical 500 series offerings, but it is remarkably useful in real world daily use. How many times have you wanted a pair of phones at the outboard rack or a pair dedicated to monitoring one thing or a separate feed for the producer or talent?