The Control One from SPL is a monitor controller in SPL's One series of high-quality audio equipment. This monitor controller offers two stereo inputs (one balanced, one unbalanced) as well as two speaker outputs, a headphone output, and a subwoofer output. As with the inputs, the output sections give you a choice of balanced or unbalanced 1/4" connection points.
An input selector lets you switch among the two sources, which you can also blend, if that is your desire. An output selector allows you to choose between your A and B output sets. Another front-panel switch sums the stereo output to mono, which can be useful for checking the integrity of your mix. You can also swap the left and right channels in order to ensure that your center elements are truly centered.
In the headphone section, note the Crossfeed knob; it engages the Phonitor Matrix, SPL's technology for emulating speaker positioning within a room, all in your headphones. With the Crossfeed knob, you can dial-in subtle amounts of the opposing channel to emulate the feeling of speakers. Mixing engineers might find this feature particularly handy when mixing in headphones.
The headphone amp itself utilizes a Class AB design and is able to power both high- and low-impedance headphones alike. You can go between your favorite consumer-grade closed-backs and your high-grade open backs without problem. A 12V external power supply unit is included.
The output stage transistors are thermally coupled and thus run particularly coherently, which contributes to a consistent and stable sound image.
The power supply has a buffer circuit with low source resistance, ensuring generous current reserves even when operating low-impedance headphones.
At the beginning of the control path, the function is not in the audio path. It is only switched on by adding it via relay (hysteresis circuit). The audio signal therefore does not pass through the crossfeed stage if this is not desired.