SRS Labs SR560 manual Input Voltage Noise, Dynamic Reserve

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CALIBRATION AND REPAIR

INPUT VOLTAGE NOISE

The amplifier's input voltage noise approximates that of a 1000Ω resistor (about 4 nV/√Hz). For source impedances below 1000Ω, the output noise will be dominated by the amplifier's input voltage noise. A typical amplifier has an input voltage noise vs. frequency as shown in the figure below. Notice that the voltage noise rises at lower frequencies (“1/f" noise).

DYNAMIC RESERVE

The dynamic reserve of the amplifier is a measure of how large a signal can be present at the input to the amplifier without causing an overload condition.

The definition of dynamic reserve is:

•DR (dB) = 20 log (Vin(f) w/o overload / Vin for full scale)

Afull-scale output voltage is 10 Vpp. Signals at the output (or at any stage) which exceed 10 Vpp cause an overload. The dynamic reserve is greater than 0 dB only when the filters are used to remove unwanted signals.

The dynamic reserve is a function of frequency and depends on the amplifier

configuration (gain, filters and dynamic reserve setting). The figure below shows the dynamic reserve (and maximum input signal without overload) for a SR560 set to a gain of 1000, the high pass filter set to 1 kHz and the low pass filter set to 10 kHz (for a bandpass from 1 kHz to 10 kHz). The dynamic reserve characteristic is shown for both "High Dynamic Reserve" and "Low Noise" gain modes.

There are several features to note. In the bandpass region between 1 and 10 kHz the dynamic reserve is 0 dB. The dynamic reserve is 3 dB at the filter frequencies of 1 and 10 kHz. The dynamic reserve rises by

6 dB/oct (or 20 dB per decade) as the signal moves away from the pole frequency, since each RC filter attenuates the signal. If a faster roll-off for interfering signals were required, a 12 dB/octave HP or LP filter could be used.

The HIGH DR characteristic offers 16 dB more DR at low frequencies and 26 dB more at high frequencies. The high frequency DR is limited only by the maximum 3 Vpp limit of the input stage.

The maximum DR in the low noise mode is 36 dB. Since there is no gain between the HP and LP filters in the Low Noise gain mode, the DR is the same at very high frequencies and very low frequencies.

The input reference voltage noise for the High DR gain mode is about 10 nV/√Hz, compared to 4 nV/√Hz in the Low Noise gain mode. The table (middle of next page) summarizes the input referenced noise and maximum dynamic reserve for all gains.

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Contents Model SR560 Page Table of Contents PCB SR560 Revision F 9/89 Schematics Calibration and RepairAppendix a Appendix BIntroduction and Setup Instrument OverviewPreparation for USE Accessories Furnished Repackaging for ShipmentUse in Biomedical Applications Environmental ConditionsPage Specifications SR560 LOW-NOISE Preamplifier Specifications ChartSpecifications Power Operation and ControlsFront Panel Operating Summary SourceFilters Gain Mode ResetGain OutputAC Power Input Amplifier Power OutputBattery Charger Rear Panel Operating SummaryBattery Care and Usage Battery CareBlanking Input RS-232 InterfaceAvoid Deep Discharge Configurable Filters and Gain Circuit DescriptionDifferential LOW-NOISE Front END Output StagesBattery Charger and PRE-REGULATORS Overload DetectionMicroprocessor Power Regulators Rear Panel InterfacesBatteries and P.E.M Front PanelOffset Adjustment Front END ReplacementCalibration and Repair CalibrationSR560 Offset Adjustment Procedure Battery ReplacementFuse Replacement Noise Contours Input Voltage Noise Dynamic ReserveMaximum Calibration and Repair Commands Appendix aRemote Programming IntroductionAppendix a Appendix B Noise Sources and CuresIntrinsic Noise Sources Non-Essential Noise SourcesCapacitive Coupling Inductive CouplingResistive Coupling or ‘Ground Loops’ MicrophonicsThermocouple Effect Appendix B SR560 Component Parts List Front Panel Parts ListMain Board Parts List 22U MIN 01U Axial 804 00225-548 Insl MTP5N05 SR560 Component Parts List SR560 Component Parts List PIN Mach SR566 Assy Adhes Tape Miscellaneous Parts List SR560 Component Parts List

SR560 specifications

SRS Labs SR560 is a cutting-edge audio enhancement technology that has gained recognition for its ability to deliver an immersive sound experience. Built upon years of research, the SR560 utilizes proprietary algorithms to achieve high-fidelity sound output while maintaining an incredibly dynamic range.

One of the most notable features of the SR560 is its adaptive audio processing, which adjusts sound dynamics based on the content being played. This means that whether one is listening to music, watching a movie, or playing video games, the sound quality is optimized in real-time to provide the best listening experience. The SR560 excels at enhancing dialogue clarity in films, ensuring that important audio elements are never lost amidst background sounds.

Another key characteristic of the SR560 is its support for multi-channel audio. With the rise of surround sound systems, the SR560 is designed to integrate seamlessly with 5.1 and 7.1 speaker setups. This ensures that users can enjoy a true surround sound experience, where each audio channel is processed independently to create a lifelike auditory environment. The SR560’s processing capabilities allow it to convert standard stereo audio into multi-channel output, enriching the listening experience for any audio format.

SRS Labs has equipped the SR560 with advanced bass optimization technology. This feature enhances low-frequency sound, providing deep, rich bass without distortion. Whether it’s the thumping beats of music or the rumble of action-packed movies, the SR560 ensures that users can experience the full spectrum of audio without compromising on quality.

Furthermore, the SR560 showcases state-of-the-art sound management features that provide users with customizable audio profiles. This allows users to tailor their audio experience according to personal preferences, whether they prefer a more balanced sound, enhanced bass, or boosted treble frequencies. The intuitive interface ensures that adjustments can be made effortlessly.

In conclusion, the SRS Labs SR560 stands out as a versatile audio enhancement technology that caters to the needs of various audio consumers. By combining adaptive processing, multi-channel support, bass optimization, and customizable profiles, the SR560 ensures a rich and immersive audio experience. As the demand for high-quality sound continues to rise, the SR560 is poised to remain a significant player in the evolution of audio technology.
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