RHPA4 Owner's Manual

4-Channel Professional Headphone Amplifier

Includes

• Headphone amplifier
• USB power cable with power supply
• Rubber feet
• Owner’s manual

Important Safety Instructions

Retain these safety and operating instructions for future reference. Heed all warnings here and on the equipment. Follow the operating instructions in this owner’s manual.

• Do not open: There are no user serviceable parts inside.
• Power sources: Only connect the unit to mains power of the type described in this user guide or marked on the rear panel. The power source must provide a good ground connection.
• Power cord: Use the power cord with mains plug appropriate for your local main supply as provided with the equipment. If the provided plug does not fit into you outlet consult your service agent. Route the power cord so that it is not likely to be walked on, stretched or pinched by items placed upon or against.
• Moisture: To reduce the risk of fire or electrical shock, do not expose the unit to rain, moisture or use in damp or wet conditions. Do not place container of liquid on it, which may spill into any openings
• Heat: Do not locate the unit in a place close to excessive heat or direct sunlight. Locate the unit away from any equipment, which produces heat such as: power supplies, power amplifiers and heaters.
• Environment: Protect from excessive dirt, dust, heat, and vibration when operating and storing.

Functions

1. Individual channel level controls: controls the volume of the specific channel’s headphone outputs.

2. LED power indicator: Will be illuminated red when the unit is powered on.

3. DC 5V Power input: Use the included USB power cable and charging block or you can plug the unit directly to any USB port with 5 volt power output.

4. Stereo/Mono switch: Determines what type of signal is sent to the output channels. It is especially useful for studio mixing/recording applications where it is common to listen to a music mix in mono in order to check for phase cancellation. Another application is if a customer is outputting from an interface that has a 1/4˝ output for the left channel and a 1/4˝ output for the right channel (stereo signal). Since the RHPA4 only has one 1/4˝ input, they have to pick one of the output channels on the interface. In STEREO mode, there will only be output to one ear. Moving the switch to MONO will allow the customer to hear the output in both ears.

5. Independent headphone outputs: All 1/4˝ and 3.5mm jacks can be used simultaneously. The volume of each set of outputs will be controlled by the corresponding level knob. Both outputs support headphones with an impedance of 16 ohms or greater and are suitable for high impedance headphones. Please note: You may experience slightly lower output when using both headphone outputs on a single channel. This is due to the fact that the outputs are wired in parallel.

6. 1/4˝ and 3.5mm inputs: These can also serve as outputs to connect a second RHPA4 unit or other headphone amp (LINK). Basically, the unused input channel becomes an output.

Input Configurations

Audio interface to Amp

Computer to Amp

Output Configurations

All 1/4˝ and 3.5mm jacks can be used individually or simultaneously. Below you will find all the possible configurations. When using both headphone outputs on a single channel, you may experience slightly lower output due to the fact that they are wired in parallel. Both outputs support headphones with an impedance of 16 ohms or greater and are suitable for high impedance headphones.

When connecting your headphones, make sure the level controls are set to MIN. Once you have connected your headphones, slowly increase the output to a reasonable level. Please note that prolonged listening at high volume can cause permanent hearing loss. Be sure to refer to the OSHA sound exposure guidelines on page 4 for maximum time exposure at specific listening levels.

One 1/4˝ headphone

Multiple 1/4˝ headphones

One 1/4˝ headphone and one 3.5mm headphone on a single channel.

Multiple 1/4˝ and 3.5mm headphones

Link Function

The 1/4˝ and 3.5mm inputs can be used to daisy chain (link) multiple RHPA4 units or other headphone amps.

1. Connect your signal source to either one of the RHPA4’s input ports (figs. a and b).

   

2. The unused input port becomes an output (figs. c and d).

   

Features

• Inputs: ¼˝ and 3.5mm input
• Stereo or Mono switch
• We include (4) ¼˝ TRS and (4) 3.5mm headphone outputs run in parallel which means you can actually run 8 headphones (2 per channel)
• 4 Outputs each output has individual volume controls
• Thick metal shell casing
• High quality potentiometer knobs for each channel
• Power “On” LED.
• DC 5V USB power supply has low power consumption
• BUS powered means you can get power to the unit from a power bank or through the USB on a computer or laptop
• Rubber feet

Specifications

• Input Impedance: 22k ohm
• Max. Input Level: +22dB
• Output Impedance: Min. 16 ohm
• Max. Gain: 20dB/Channel
• S/N Ratio: >98dB
• Frequency Response: 20 – 20kHz
• S/N Ratio: >90dB (ref 0dBu)
• THD: <0.01%
• Power supply: 5V DC, ≥1000mA via USB Power Adaptor
• Dimensions: 4.6˝ x 3˝ x 2.36˝
• Weight: 0.85 Lbs
• 0dBu = 0.775Vrms

Troubleshooting

No Power:

Make sure the USB power cable is properly plugged into the unit as well as the power supply or the computer’s USB port.

No Sound:

1. Make sure that the input cable (¼˝ or 3.5mm) is properly connected.
2. Check the channel level knobs as well as the input source’s volume control.
3. Be sure your headphones are properly plugged in.