CM-HPR1 Headphone Volume Control
This product 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 150? 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? set of headphones looks like 600? 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-HPR1
The stereo analogue input is on a female RJ45 connector with the following standard StudioHub+™pin assignments:
| Pin No |
Connection |
| 1 |
Left Phase |
| 2 |
Left Non-Phase |
| 3 |
Right Phase |
| 4 |
Ground |
| 5 |
N/C |
| 6 |
Right Non-Phase |
| 7 |
N/C |
| 8 |
N/C |
| 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-HPR1
The stereo analogue input is on a female RJ45 connector with the following standard StudioHub+™pin assignments:
| Pin No |
Connection |
| 1 |
Left Phase |
| 2 |
Left Non-Phase |
| 3 |
Right Phase |
| 4 |
Ground |
| 5 |
N/C |
| 6 |
Right Non-Phase |
| 7 |
N/C |
| 8 |
N/C |
CM-HPR1 Technical Specification
|
Audio Specification
|
|
| Input/Output Level Ratio: |
2:1 |
| Input/Output Impedance Ratio: |
4:1 |
| Minimum Headphone Impedance: |
150O |
| 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 |
| |
|
Connections
|
|
| 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 |