Setting Up and Operation

Sample Rate Converters

The sampling frequency of the audio data embedded in SDI video signals is 48 kHz. This is invariant, and is enshrined in the defining standards for all SDI formats. As with all operations involving digital audio, it will generally be desirable for the audio outputs of the SDI-MADI to be synchronised (in frequency and/or phase) with a master reference clock, which will also synchronise all other digital audio processing in the facility.

To achieve this, the SDI-MADI includes four 16-channel Sample Rate Converters (SRCs), one for each SDI input (see Rear Panel Description on page 8). Each SRC may be switched in or out by a front panel switch (see Front Panel Description on page 7) or by external control via the GPIO port. When each SRC is active, a red LED illuminates, and a tally output voltage is also available at the rear GPIO port. When enabled, the SRCs re-clock the audio data against a new reference, thereby changing the sampling frequency of the data to that of the reference. They also ensure that the word blocks in the data are phase-locked exactly to the reference clock. The SDI-MADI allows the user to select a reference clock source to suit the infrastructure of the facility and the nature of the transfer process.

See following section on “Synchronisation”

GPIO Control

As the SDI-MADI could be installed in a central control room or outside broadcast vehicle using automated system software applications, external control of the SRCs can be achieved via the GPIO port. Simple contact closure (grounding the GPI) enables any or all the SRCs, allowing them to be switched in or out from a remote point. Maximum recommended operating distance is 5 m (though this may be increased by the use of external relays or similar).

Refer to the pinout on page 12 for wiring details.

Synchronisation

The SDI-MADI offers a choice of wordclock synchronisation sources. The selection is made from the front panel, and the array of LEDs confirms the currently-selected source. The selected source is used as reference for all four output SRCs, thus ALL audio outputs, both in AES3 and MADI formats, will be locked to the selected reference. The various clock sources are discussed on the following page.

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Solid State Logic 1266 manual Setting Up and Operation, Sample Rate Converters, Gpio Control, Synchronisation
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1266 specifications

The Solid State Logic 1266 is a premium analog channel strip renowned for its versatility and high-quality audio processing. This channel strip combines sophisticated features, advanced technologies, and the renowned SSL sound, making it a favorite among audio engineers and producers.

One of the standout features of the SSL 1266 is its classic SSL EQ, which boasts four bands of equalization. Each band offers selectable frequency ranges, allowing users to perform precise tonal adjustments. The high and low bands can operate as shelving or peak filters, providing flexibility in shaping sound. This powerful EQ section is complemented by a dynamic section, which includes an LED-level meter and a compressor/limiter. The compressor is characterized by its smooth response, allowing for detailed dynamic control over tracks, while the limiter provides an additional safety net for preventing signal clipping.

Another key feature is the inclusion of the iconic SSL mic preamp circuitry. The 1266 is equipped with a transformer-balanced mic pre, designed to deliver warmth and presence to vocals and instruments. It provides ample gain, ensuring the ability to capture signals clearly, even from low-output microphones. The design is meticulous, featuring very low noise and distortion levels, resulting in pure, transparent sound reproduction.

The SSL 1266 also incorporates the brand's proprietary 'SuperAnalog' technology, which enhances the overall sonic performance. This technology ensures low noise and high headroom, allowing the channel strip to handle high-level signals without compromising audio integrity. Additionally, the unit is designed with a robust build quality, featuring a durable chassis and high-grade components that ensure longevity and reliability in studio environments.

Furthermore, the 1266 includes features such as a high-pass filter and an insert point for integrating external processors, providing even more flexibility in sound design. It is also equipped with a line input and a balanced output, further enhancing connectivity options.

The Solid State Logic 1266 channel strip exemplifies the perfect blend of classic analog warmth and modern functionality. It caters to a wide range of applications, from tracking to mixing, making it an indispensable tool for any audio professional seeking to elevate their sound. With its comprehensive features and SSL's legacy of quality, the 1266 is a worthy investment for those aiming for excellence in audio production.
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