sonifex cm hpr1

TheSonifex CM-HPR1  allows the connection of a stereo balanced line input via a RJ45 with StudioHub+™ pinout and creates a headphone output, with level control. It is transformer balanced, and can be used with any headphones above 150Ω 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 150Ω set of headphones looks like 600Ω at the input, a suitable load for most good quality line output stages).

Block Diagram

CM-HPR1 Diagram

Connectors & Controls

Headphone Output

The stereo headphone output uses a stereo 6.35mm jack socket with the following connections:

Pin TypeConnection

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-HPR1

The stereo analogue input is on a female RJ45 connector with the following standard StudioHub+™pin assignments:

Pin NoConnection
1Left Phase
2Left Non-Phase
3Right Phase
6Right Non-Phase

Audio Specification

Input/Output Level Ratio:2:1
Input/Output Impedance Ratio:4:1
Minimum Headphone Impedance:150Ω
Max Input Level:+28dBu
Max Output Level:+22dBu
Frequency Response:20Hz to 20kHz, +0/-0.5dB
Noise:<-115dBu A-wgtd
Distortion Ref +8dBu (Output):<0.01%
Common Mode Rejection:>80dB


Main Stereo Input:1 x RJ45 female StudioHub+™ pinout
Output:¼” (6.35mm) A/B gauge 3-pole stereo jack sockets

Equipment Type

CM-HPR1:Headphone volume control, RJ45 input

Physical Specification

Dimensions (Raw):7.7cm (W) x 8.3cm (D) x 4.2cm (H) 3.0” (W) x 3.3” (D) x 1.7” (H)
Dimensions (Boxed):12.7cm (W) x 22.9cm (D) x 7.6cm (H) 5” (W) x 9” (D) x 3” (H)
Weight:Nett: 0.22kg Gross: 0.33kg Nett: 0.49lbs Gross: 0.73lbs
BW Price Guarantee

(Subject to conditions)

Sonifex CM-HPR1


Tech Support

2-Year Warranty


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