Follow this basic procedure for setting up and using your QH4 4-Channel Headphone Amplifier.
NOTE: Before you connect any headphones to the QH4, be sure to double check that the signal source and QH4 amplifier level controls are turned all the all the way down to their fully counter clockwise positions. The QH4 can generate loud signal levels into the connected headphone. We recommend that you exercise extreme caution and care for your ears. Always start with the level controls all the way off and slowly raise the signal to a comfortable listening level.
- Turn the MASTER Volume knob all the way down until it is in the off-position (rotate counterclockwise until it clicks), and turn all four headphone channel volume knobs to their minimum (fully counterclockwise) setting.
- Connect the included power supply to the QH4, and plug it into an AC wall socket, but leave its power off for the moment.
- Connect the outputs from the device you want monitored to the Left and Right INPUTS on the QH4 rear panel. The QH4 accepts both balanced and unbalanced signals. It is recommended to use balanced 1/4” TRS cables because it minimizes extraneous noise from entering the signal path.
- Connect headphones to the 1/4” headphone output jacks.
- Play an audio signal into the QH4 inputs.
- Raise the MASTER volume half way (to the 12 o’clock position).
- Slowly turn the channel’s level knob clockwise until you hear the desired level.
- Repeat the previous step for all Channels that have headphones connected, making sure to start with the Headphone Volume knob completely counter- clockwise and then slowly raising it until the desired level is achieved.
- To expand the QH4 to allow for more than four individual headphone outputs, you can connect multiple QH4 amplifiers together by plugging a 1/8” stereo cable into the Aux Output of the first QH4 amplifier and the Aux Input of another QH4 amplifier. You can repeat this step to add as many headphone amplifiers as necessary. The Aux Output jack is after the MASTER Volume/Power control, Mute and Mono switches, so all adjustments to these controls will affect units further down the chain.
If you have connected different models of headphones to the QH4, you may find that some require more gain than others to achieve the same volume. This kind of disparity occurs if the headphones have different sensitivities of different impedances. The lower the impedance, the louder the headphone will sound compared to another, higher impedance headphone at the same volume setting. Sensitivity is measured by determining the decibel (dB) level generated by 1 mW of power input. The higher the dB rating, the louder the headphone