The PC-USB connection on your Rotel device has two USB settings. The default setting is USB Class 1.0, which supports audio up to 96kHz. In order to support 192kHz audio, your Rotel device must be set to USB Audio Class 2.0 in the setup menu, and if you are using a Windows PC you must also make sure the USB 2.0 drivers are installed. Also, you may need to adjust the sample rate output on your computer as well.

For Windows PC users, you can find the USB 2.0 drivers on the CD included with your Rotel product, or you can download the drivers here.

Changing the Rotel device to USB Class 2.0

For models with a front display, to change the USB class to 2.0, press the MENU button repeatedly until you reach the menu PC-USB AUDIO CLASS, then change this setting to 'USB 2.0'.

For the RDD-1580 DAC, follow the steps below to change the USB Audio Class:

1. Press and Hold the PC-USB source button on the front panel for 5 seconds. The current USB audio mode is indicated by the blinking Sample Rate LED as: 
   • USB Audio Class 1.0 – Sample Rate 96kHz blinking (Factory Default)
   • USB Audio Class 2.0 – Sample Rate 192kHz blinking
2. Press the PC-USB key again to illuminate the 192kHz sample rate light blinks.
3. Pressing the PC-USB key will toggle between USB Audio Class 1.0 (96kHz light blinks) and USB Audio Class 2.0 (192kHz light blinks).
4. After the desired USB Audio mode is selected wait 3 seconds for the selection period to end and the RDD-1580 will use the selected audio mode.
5. Power cycle the RDD-1580 and reboot your PC after changing the USB Audio mode to ensure both units are properly configured.

Adjusting the Sample Rate on the Computer

If your Rotel device has already been set to USB 2.0 (and the driver has been installed if you are using a Windows PC), the next step would be to check/adjust the sample rate settings on your computer.

• Mac OS X Users - Select Applications->Utilities->Audio MIDI Setup, then highlight the Rotel audio device from the list on the left side of the Audio Devices window. Choose "Use this device for sound output" if this has not already been selected. From this menu you can also select the desired Sample Rate to use, so if you are going to be listening to high-resolution audio files select the appropriate sample rate setting from the Format menu here as well.
  
  
• Windows Users - Select Start->Control Panel->Sound and Audio devices->Playback, then select the Rotel audio device from the list and select 'Properties'. Click the 'Advanced' tab and choose the desired sample rate from the Default Format tab.

An important note about changing the output format - since most of the recordings you will play from iTunes will have been ripped from 44.1kHz CDs, you will want to play them back at their native rate, so the computer needs to be set up to output 44.1kHz. If you leave it set at a higher resolution (96kHz, 192kHz etc), the computer will convert the audio up to this higher resolution which can reduce the sound quality, so it is important to only adjust the sample rate when you intend to play higher resolution audio files.

Software packages like Pure Music and Amarra are available for Mac users to help manage things like automatically playing back music files using their native rate. This eliminates the need to manually make changes if you frequently switch between 44.1kHz and 96kHz or 192kHz recordings.

Digital audio signals and analog audio signals are kept separate from each other. The multizone circuitry in Rotel surround receivers and preamp/processor is analog. If you have digital connections from your CD player or DVD player to your home theater receiver or preamp/processor, you must also use analog connections (RCA connecting cables) from your source components to the CD or DVD player input on the receiver or preamp/processor.

Do note that in addition to analog sources, the front USB source is also available in the remote zones on RSP-1572 and RSX-1562.

The red protection LEDs for Rotel amplifiers can behave slightly differently depending upon the design of the amplifier in question.

On Class AB models such as RB-1582, RB-1552 and RMB-1506, as well as the RB-1562 the protection LEDs will click on briefly then turn off whenever the power amplifier is powered up or powering down into standby mode. For example, when using the 12V trigger to power the amp on or off, the LEDs will briefly turn on to signify the amp is now on. When the system is turned off the protection LEDs will again turn on briefly when the amp shuts down.

On Class D models such as RB-1572, RB-1510, RMB-1565, RMB-1575 or RMB-1512 the red protection LEDs will remain lit whenever the amplifier is powered down into standby mode. This is the case when using the 12V trigger to power the amplifiers on or off; the red protection LED will remain lit whenever the system is off, and will go out when the amplifiers are powered up. N

ote that in either case if the power amplifiers are turned off via the front panel power button all of the front panel LEDs will be off. The above circumstances refer to using either 12V trigger or signal sense modes to control power to the amplifiers.

The protection LEDs for Rotel amplifiers will also of course light up if the unit has experienced a fault and is in fact in protection mode. In this case the LED would remain lit at all times.

This is likely due to the Auto Power Off timer on the unit. The default setting for units sold in the UK and EU markets is 20 minutes. All other regions default the power off timer to Disabled.

Recent EU and UK power regulations mandate that all products offer an automatic power off feature after a set period of inactivity. Leaving the CD player Paused or Stopped will start this timer.

To adjust this, simply go to the Setup menu by pressing the MENU key on the remote control and change the timer or set it to Disabled.