Weiss SFC 2

The SFC2 is a versatile sampling frequency converter with two completely independent stereo converters in a single 19 inch (1HU) unit. A SFC basically consists of a high order, linear phase, digital low pass filter. With the proper design of that low pass filter the quality of the SFC process can be made “arbitrarily” good – independent of the conversion ratio. Like what we achieved in the SFC2.

Standard sampling frequency converter chips continuously measure the input frequency and then generate the output frequency and the filter specifications accordingly. This results in coefficient “jitter” because the input signal sampling frequency jitter modulates the cutoff frequency of the digital filter. The SFC2 uses a fixed-ratio scheme where the output is directly derived from the input sampling frequency – therefore no coefficient “jitter”, no filter modulation, more transparency.

The main application of the SFC2 is integrating playback or outboard equipment into an environment that either runs at double- or standard-sampling frequency. To allow this equipment to be positioned anywhere in the processing chain, the SFC2 features two completely independent two-channel sampling frequency converters to simultaneously down- and up-sample a signal. Alternatively, it can also be used to convert the sampling frequency and reduce the word-length of any two stereo audio signals at the same time.

The two sections of the SFC2 have the same feature set. They sport AES/EBU inputs and outputs on XLR connectors and work at the four standard sampling frequencies of 44.1, 48, 88.2 and 96 kHz. The word-length at the output can be set to 24, 20 or 16 Bits. For proper word-length reduction, dithering must be switched on. Dithering in the SFC2 uses a second order noise-shaping process. The dither noise can be set to be automatically muted in music pauses.

Power

Size

AES/EBU Input

AES/EBU Output

Dither

Transparency

The SFC2 is Bit-transparent with a conversion ratio of 1:1