Weiss Engineering GAMBIT SFC2 Operating Manual

digital audio

weiss engineering ltd.
Florastrasse 42, 8610 Uster, Switzerland

) [phone] [phone]
8 http://www.weiss.ch / http://www.weiss-highend.com

GAMBIT

SFC2

OPERATING MANUAL

Software Version: 0S: 1.0

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 CONTENTS

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 2 of 8

) [phone] [phone] http://www.weiss.ch

CONTENTS

CONTENTS ___________________________________________________________________2
FRONT PANEL ________________________________________________________________3
INTRODUCTION ______________________________________________________________4

Features_____________________________________________________________________________4

OPERATION __________________________________________________________________5

Connections__________________________________________________________________________5
Changing Output Sampling Frequency _____________________________________________________5
Dither_______________________________________________________________________________5

TECHNICAL DATA ____________________________________________________________6

AES/EBU Input A & B __________________________________________________________________6
AES/EBU Output A & B_________________________________________________________________6
Power_______________________________________________________________________________6
Dither_______________________________________________________________________________7
Conversion Spectra ____________________________________________________________________8

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 FRONT PANEL

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 3 of 8

) [phone] [phone] http://www.weiss.ch

FRONT PANEL

Œ

•

Ž

Graph 1: Front Panel Elements

The front panel of the SFC2 offers several control and display features. These can be grouped according to Graph 1:

Π- Control Elements for Channel A

• - Control Elements for Channel B
Ž - Mains power switch

This manual will explain how to operate the SFC2 according to these groups

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 INTRODUCTION

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 4 of 8

) [phone] [phone] http://www.weiss.ch

INTRODUCTION

Congratulations on purchasing the Weiss Gambit Series SFC2 !

The main function of the SFC2 will be 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, A & B, to simultaneously
down- and up-sample a signal. Alternatively, it
can also be used to convert the sample fre­quency and reduce the wordlength of any two
arbitrary audio signals at the same time.

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. However, 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.

Features

Auto detection and display of input sam-

pling frequency

Selection of output sampling frequency

with large, backlit push buttons

Supported input and output sampling fre-

quenncies:

44.1 / 48 / 88.2 / 96 kHz

Bit transparent for 1:1 conversions

24bit I/O on single wire AES/EBU inter-

faces

Noiseshaped dither for wordlength reduc-

tion of output signal to 16 or 20bit

Selectable autoblacking for dither – mutes

dither if no signal present.

40bit floating point digital signal processing

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 OPERATION

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 5 of 8

) [phone] [phone] http://www.weiss.ch

OPERATION

Connections

Connect the AES/EBU signal to the input and
output plugs at the rear of the SFC2.

The sampling frequency of the connected signal
will either display in Œ (channel A) or in •

(channel B), according to which channel was cho-

sen.
Two stereo signals can be connected simultane-

ously to the the two channels A and B – they
need not be in sync.

Changing Output Sampling Fre­quency

If none of the push buttons are pressed (none of
the buttons is lit), the SFC is in input signal follow
mode: the output will always be at the same
sampling frequency as the input. If no dither is
selected, then the output will be bit equal to the
input in this mode.

To choose another output sampling frequency,
simply press the appropriate button – it will be lit
so that the status of the SFC can be confirmed
visually.

Dither

The SFC2 is able to apply shaped dither noise to
remove distortion when re-quantizing from 24bit
to 16bit or 20bit output word length (see
TECHNICAL DATA for dither specifications).

To toggle dither on/off, press the button marked
“dither” in the “dither output settings” field. The
button is lit when dither is active.

Word Length and Autoblacking

Pressing the “mode” button int the “dither out­put settings” field will toggle through the follow­ing modes:

- 16bit without autoblacking

- 20bit without autoblacking

- 16bit with autoblacking

- 20bit with autoblacking

The selected mode is displayed above the
“mode” button.

If auto-blacking is activated, dither will be turned
off if the input signal is digital zero for more than
256 consecutive samples. As soon as the input
signal changes, dither will be turned on again.
This ensures that breaks between programs are
still at digital zero, regardless of dither.

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 TECHNICAL DATA

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 6 of 8

) [phone] [phone] http://www.weiss.ch

TECHNICAL DATA

AES/EBU Input A & B

Sampling Frequencies: 44.1 kHz, 48.0 kHz, 88.2 kHz, 96kHz
Maximum Input Wordlength: 24 Bits
Channel Status Data: Input accepts professional or consumer format.
Channel Status Bits
forwarded to AES/EBU output: all
Connector: XLR female

AES/EBU Output A & B

Sampling Frequencies: 44.1 kHz, 48.0 kHz, 88.2 kHz, 96kHz
Output Wordlength: 24 Bits
Connector: XLR male

Power

Mains Voltage: 110 / 220 Volts with voltage selector
Fuse rating: 500 mA slow blow
Power Consumption: 40VA max

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 TECHNICAL DATA

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 7 of 8

) [phone] [phone] http://www.weiss.ch

Dither

If no dither is applied to the digital signal when recording to 16bit or 20bit media (e.g. DAT, CD-R etc), the signal will
be truncated, which leads to quantization noise. Graphic 2 shows a 24bit sine wave at –85dBFS truncated to 16bit.

Graphic 2: Sine wave truncated

Graphic 3 shows the same sine wave, but dithered to 16bit. This eliminates quantization distortion.

Graphic 3: Sine wave dithered

OPERATING INSTRUCTIONS FOR GAMBIT SFC2 TECHNICAL DATA

Daniel Weiss Engineering Ltd., Florastr. 42, CH-8610 Uster Page 8 of 8

) [phone] [phone] http://www.weiss.ch

CONVERSION SPECTRA

1kHz Sine 0dB Converted From 96kHz to 44.1kHz

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

0 5383 10767 16150 21533

Frequency [Hz]

Amplitude [dBFS]

1kHz Sine 0dB Converted From 44.1kHz to 96kHz

-180

-160

-140

-120

-100

-80

-60

-40

-20

0

0 11719 23438 35156 46875

Frequency [Hz]

Amplitude [dBFS]