The Sonifex CM-HPX1 Headphone Volumn Control allows the connection of a stereo balanced line input via 2 x female XLRs and creates a headphone output, with level control.
It is transformer balanced, and can be used with any headphones above 150 Ω impedance. The transformer ratio of 2:1 ensures that any headphone load presented at the output is reflected through to the input at a 1:4 ratio (hence a 150 Ω set of headphones looks like 600 Ω at the input, a suitable load for most good quality line output stages).
Block Diagram
Connectors & Controls
Headphone Output
The stereo headphone output uses a stereo 6.35mm jack socket with the following connections:
| Pin Type | Connection |
| Tip: | Left |
| Ring: | Right |
| Screen: | Ground |
The headphone level will be at half the level of
the incoming signal with the volume control at 100%.
Volume Level Control
The volume level control sets the output level of the stereo headphone socket and runs logarithmically from zero to the maximum output level.
Analogue Inputs CM-HPX1
The stereo analogue input is on two female 3 pin
XLR connectors with the following pin assignments:
Pin 1: 0V Common
Pin 2: Phase
Pin 3: Non Phase
