Rotel RA-1520 owner manual Audio Controls, Protection Circuit

	RA‑1520 Stereo Integrated Amplifier
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Audio Controls

The following controls are used to operate the RA‑1520.

VOLUME Control 0C

Turn the front panel VOLUME control clockwise to increase the volume, or counterclockwise to decrease the volume. Alternatively, press the VOL buttons on the remote control to adjust the volume up or down.

BALANCE Control -

The Balance Control adjusts the left-to-right balance of the sound output. Normally the control should be left in the center position. In some situations, typically when the main listening position is not ideally centered between the speakers, it may be necessary to adjust the control to achieve proper left-to-right balance. Turning the control counter-clockwise shifts the sound balance to the left. Turning the control clockwise shifts the sound balance to the right.

BASS and TREBLE Tone Controls 79

These two front panel rotary controls are used to make adjustments to the tone or contour settings, boosting or cutting high frequencies (TREBLE) and low frequencies (BASS). If tone adjustments are not required, the tone control circuit can be bypassed by using the TONE On/Off switch.

TONE On/Off 8

When this button is in the ‘off’ position (with the button out) the BASS and TREBLE tone controls are inoperative. This setting gives a more direct signal path and may give a small improvement in sound quality for critical listening.

LISTENING Selector qB

The setting of the LISTENING selector controls which of the input signals goes to the main outputs and onto the power amplifier – or, more simply, which source is heard. Turn the front panel control to the source you want to hear, or press the corresponding button on the RR‑AT94 remote.

RECORDING Selector =

The RA‑1520 can record from any input source (except TAPE 2) to a recorder connected to TAPE 1 or TAPE 2 outputs. To select an input source for recording, turn the RECORDING control on the front-panel to the desired source.

This selection is independent of the source selected for listening. While recording, you may still select a different source using the LISTENING selector.

If you have a three-head recorder or a DAT recorder that allows simultaneous read and write operation, you can monitor your recording by setting the LISTENING switch to the TAPE 1 or TAPE 2 position.

Note: If you select TAPE 1 with the RECORDING control, the recording signal will only be available at the TAPE 2 recording outputs, not the TAPE 1 outputs. To dub a tape, select TAPE 1 and record to the tape deck connected to the TAPE 2 outputs.

MUTE Button A

To temporarily mute the sound of the system press the MUTE button on the RR‑AT94 remote. Press the button again to return the sound volume to the original level. The LED in the volume control will flash when the unit is muted.

PHONES Output 5

The PHONES output allows you to connect headphones for private listening. This output accepts standard stereo 1/8” stereo mini plugs.

If your headphones have a 1/4” plug, you will need an adapter plug. Contact your authorized Rotel dealer, to get the correct adapter plug.

Note: Plugging in headphones does not cut off the signal to the speakers. If desired, use the SPEAKERS selector to turn off the signal to the speakers for private listening.

SPEAKERS Selector 6

A four-position rotary switch on the front panel determines which set of speakers, if any, is active. Set the SPEAKER selector as follows:

OFF: No speakers will be heard. Use this position when listening to headphones.

A:The speakers connected to the SPEAKER A terminals will be heard.

B:The speakers connected to the SPEAKER B terminals will be heard.

A+B: The speakers connected to both the SPEAKER A and SPEAKER B terminals will be heard.

Protection Circuit

Protection Indicator 2

Thermal protection circuits protect the amplifier against potential damage in the event of extreme or faulty operating conditions. Unlike many designs, the RA‑1520 protection circuit is independent of the audio signal and has no impact on sonic performance. Instead, the protection circuit monitors the temperature of the output devices and shuts down the amplifier if safe limits are exceeded.

In addition, the RA‑1520 includes over-current protection which operates only when load impedances drop too low. This protection is independent for each channel and is indicated by the front panel Protection LED.

Should a faulty condition arise, the amplifier will stop playing and the Protection LED on the front panel will light.

If this happens, turn the amplifier off, let it cool down for several minutes, and attempt to identify and correct the problem. When you turn the amplifier back on, the protection circuit will automatically reset and the PROTECTION LED should go out.

In most cases, the protection circuitry activates because of a fault condition such as shorted speaker wires, or inadequate ventilation leading to an overheating condition. In very rare cases, highly reactive or extremely low impedance speaker loads could cause the protection circuit to engage.