OPERATION

The SR554 Transformer Preamplifier is designed to be used with all SRS Lock-in amplifiers. It can reduce input noise of a lock-in amplifier dramatically (as low as

100pV/√Hz) and extends the lock-in’s full scale sensitivity (without expand). It also nearly eliminates noise radiated back from the lock-in amplifier to the users experiment. When used as a remote preamplifier, the SR554 can eliminate the effects of noise pickup on long signal cables. The SR554 transformer is designed to be used with its internal buffer, but the buffer may be bypassed for transformer only operation. When used as a simple transformer, no power connection is required.

CONNECTING THE SR554

When the transformer and buffer are used together, power is supplied to the SR554 via the 9 pin connector and cable. This cable mates with all SRS lock-in amplifiers through the rear panel connector. To use the SR554 without an SRS lock-in, the user must provide their own ±20 VDC (100 mA) source. Always connect the power cable to the SR554 while the lock- in power is off. Attach one end of the cable to the connector on the rear of the SR554, and connect the other end to the PRE-AMP connector on the rear of the lock-in. If a longer cable is required, any standard 9 pin cable will suffice since all connections are straight through. When the lock-in power is on, the POWER

indicator on the SR554 will light.

The SR554 output switch selects between buffered mode with a gain of 500, (transformer and buffer) or bypassed mode with a gain of 100 (transformer alone). In the buffered mode, the transformer secondary goes into a low noise buffer which drives the output cable. This is to reduce loading due to the transformer output impedance (about 5 kΩ) and cable capacitance (10's of pf). If the user prefers not to use the buffer or if power isn’t available for the preamp, then the SR554 can be used in the bypassed mode. In the bypassed mode, the output impedance of the pre-amp is 5 kΩ and care must be taken to avoid loading the output with too much cable capacitance. Power should not be connected to the SR554 when used in the bypass mode.

INPUT CONNECTION

Signals into the SR554 can be connected either single ended through the (A) input, or differentially through the (A-B) inputs. In the single ended configuration the shield and center conductor of the (A) input are connected to the transformer. For differential connection, the shields of the input BNC’s are connected to the SR554 case and the (A) and (B) center conductors connect to the transformer.

The input impedance is a combination of 0.5 Ω and 0.5 H (in series) in parallel with

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SRS Labs manual Connecting the SR554, Input Connection
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SR554 specifications

SRS Labs SR554 is an advanced audio processing solution that aims to enhance audio quality across various media platforms. Recognized for its innovative approach to sound enhancement, the SR554 incorporates a variety of technologies designed to create a richer, more immersive listening experience.

One of the standout features of the SRS Labs SR554 is its Superior Sound technology, which employs advanced algorithms to optimize audio output for different types of content. Whether users are listening to music, watching movies, or playing video games, the SR554 intelligently adjusts the audio output to suit the specific requirements of each medium. This adaptability is crucial in today’s diverse audio landscape, ensuring that users enjoy the best possible sound quality regardless of the source.

The SR554 also integrates SRS's renowned TruBass technology, which enhances low-frequency audio signals to produce deeper, more resonant bass without sacrificing clarity. This feature is particularly beneficial for genres such as hip-hop and electronic dance music, where bass plays a pivotal role in the overall impact of the audio experience. By creating a more balanced and full-bodied sound, the SR554 caters to audiophiles and casual listeners alike.

Additionally, the SR554 is equipped with SRS Virtual Surround technology, which simulates a multi-channel audio experience from standard two-channel setups. This feature provides users with an enveloping soundstage, making it ideal for home theater systems and gaming setups. By creating a perception of height, width, and depth in sound, the SR554 enhances the realism of audio playback, making users feel as though they are part of the action.

Compatibility is another key characteristic of the SR554. The solution supports a wide range of audio formats, ensuring that it can seamlessly integrate into various devices and platforms, from smartphones to high-end audio systems. This versatility allows users to experience enhanced audio quality no matter how or where they choose to consume their media.

In terms of user customization, the SR554 offers an array of adjustable settings, allowing users to tailor their audio experience according to their preferences. This tailored approach means that whether someone seeks a more vibrant sound or a subtle auditory atmosphere, the SR554 can be fine-tuned to meet those needs.

In summary, the SRS Labs SR554 stands out in the crowded audio enhancement market through its innovative technologies geared towards delivering superior sound, enhanced bass, and immersive audio experiences. Its adaptability, compatibility, and customization options make it a compelling choice for anyone seeking to elevate their audio experience across a wide range of media formats.
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