Knowledge Base


OPPO HA-1 Headphone Amplifier

Understanding the HA-1's Analog Volume Control

The HA-1 uses a pure analog audio path after its DAC. The volume is adjusted by rotating a potentiometer by hand or by motor via the remote control. The numeric volume display is created by taking samples of a voltage divided by the potentiometer. The numeric dB value displayed on the screen is based on the measurement of the volume knob position. It indicates the approximate gain or attenuation level of the pre-amplifier output relative to the input signal. It is normal for the display value to vary a few dB when the volume knob moves in the very low range due to the logarithmic nature of the volume control curve.

When using the remote control to reach a certain numeric dB value, the following should be taken into consideration:
1. The time it takes to measure the potentiometer position and average multiple measurements to get a reliable reading.
2. The human reaction time from seeing the desired dB value onscreen to releasing the remote control button.
3. The "de-bounding" time for processing the "button up" event, so that the HA-1 knows the button is indeed released and it is not a signal interference or button contact glitch. These three events occur while the knob is still rotating. As a result, when you are using the remote control to adjust the volume level and you see the desired dB value on the screen and release the button on the remote control, the knob will overshoot a bit. If you need to turn the volume knob to a very specific numeric dB value, we recommend turning the knob by hand slowly or pressing the remote volume buttons in repeated single clicks. Pressing and holding the volume button on the remote control serves as a convenience feature for rotating the volume knob rapidly, and it is not designed to precisely reach a certain dB value. Ultimately, if you are accustomed to digital volume controls that can be rapidly dialed in to a certain dB value, the analog volume control on the HA-1 may take some getting used to. However, once you become familiar with it, you will appreciate its very fine volume adjustment, fluid movement, and great sound.

Installing the OPPO USB DAC Driver for HA-1 and HA-2

To use the OPPO HA-1 and OPPO HA-2 with your Windows computer, you will need to download and install the driver located on the Support page for the associated product.

HA-1: http://www.oppodigital.com/headphone-amplifier-ha-1/headphone-amplifier-HA-1-Support.aspx

HA-2: http://www.oppodigital.com/headphone-amplifier-ha-2/headphone-amplifier-HA-2-Support.aspx

Note: the same software driver will work for both devices.

Once the .zip file has finished downloading, extract the contents to a location on your computer such as the Desktop.

Go into the File Folder that you extracted to the Desktop, and run the "setup.exe" application. Click on the affirmative option for the various prompts, and the driver installation process will begin.

Run Setup

Once the installation has completed, follow the instructions and turn the OPPO device off and then back on. Windows will be able to associate the proper driver with your OPPO device at this point.

Device Manager should then look like this:

Properly Installed

In some rare cases, Windows may assign a generic USB audio driver to the OPPO device, and you will need to manually select what driver you want to use. Device Manager will list the OPPO device with an exclamation mark icon, as seen below:

Driver Not Installed

To have Windows use the correct driver, you will need to open Device Manager and right-click on the "OPPO HA-1 USB Audio 2.0 DAC" item under "Sound, video and game controllers" and select "Update Driver Software..." This will open another window that will give you the option to either search for another driver automatically, or manually browse your computer for the driver.

Manually Select

Select the option to "Browse my computer for driver software". Another window will open allowing you to search a specific location on your computer for the driver. You will need to click on the "Browse..." button and select the location on your computer where you extracted the contents of the driver's .zip file. Click "Next", and Windows should find and install the proper driver. Once the installation is complete, using the HA-1 or HA-2 as your computer's external DAC is merely a matter of setting the OPPO as your default sound playback device in the Windows Control Panel:

Sound Control Panel

Note: if you use 3rd-party playback software such as Foobar2000 or JRiver, you will need to configure those individual programs to utilize the OPPO HA-1 or HA-2 as your sound playback device.

Unit Appears to Power Off Immediately After Powering On

If your OPPO HA-1 appears as though it is immediately powering off after powering the unit on, it is likely due to having set the Screen Dimmer setting to Off.

A quick way to determine whether the unit has actually powered off is to turn the volume knob on the HA-1. If the Screen Dimmer mode is set to Off , the HA-1's display will briefly turn back on to indicate the current volume level when the volume knob is turned.

The Screen Dimmer setting can be adjusted via the HA-1's user interface, or by pressing the Dimmer button on the included remote control.


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