Callia Operation Manual by Ian Dennis
Table of Contents Part 1 General information 2 Part 2 Introduction to Callia 6 1 Features ................................................................................................................................. 6 2 Getting ................................................................................................................................. started 7 3 System ........................................................................................................................
Part 1 General information
Prism Sound Callia 1 Operation Manual Revision 1.01 General information Manual revision history Rev Date 1.00 8th March 2016 1.01 12th August 2016 Author I.G.Dennis I.G.Dennis Notes Product Launch Added Linux support details The latest version of this Operation Manual can be downloaded from the Prism Sound website at www.prismsound.com. It is provided in PDF format which can be viewed and printed using the Adobe Acrobat Reader, available free at www.adobe.com.
Prism Sound Callia Operation Manual Revision 1.01 Statements of conformity This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against interference in a residential area. This device generates and uses radio frequency energy and, if not installed and used in accordance with the instructions, may cause interference to radio or TV reception.
Part 2 Introduction to Callia
Prism Sound Callia 2 Operation Manual Revision 1.01 Introduction to Callia Callia is a USB and S/PDIF D/A converter and pre-amplifier for domestic use. Prism Sound A/D and D/A conversion has been the technology of choice in the world's top recording and mastering studios for over 20 years; Callia brings the conversion quality of these renowned facilities into your home for the first time. For a summary of Callia's capabilities, continue to the Features section.
Prism Sound Callia Operation Manual Revision 1.01 Controls and indicators · Automatic or manual source selection · Source format and wordlength indication · Line volume control, can be disabled for use with external pre-amplifiers (line outputs may be optionally muted by headphones) · Dedicated headphone volume control · Adjustable front panel illumination to match ambient lighting PSU · High reliability, low noise, universal input (90-260Vrms) mains PSU · Low-power standby mode 2.
Prism Sound Callia Operation Manual Revision 1.01 · Connect Callia's analogue outputs to a monitoring amplifier or active speakers, using the XLR or RCA analogue output connectors. Make sure that the volume of the amplifier or speakers is turned down until we're sure everything is OK. On the other hand, you could just plug in some headphones - make sure the headphone volume control is backed off to start with. · Connect Callia to the mains using the power lead provided.
Part 3 Installation procedures
Prism Sound Callia 3 Operation Manual Revision 1.01 Installation procedures This section contains detailed installation instructions for your Callia. If you are keen to get going quickly, you could use the Getting started section above. The following sections describe installation for Windows and Mac systems. Note that Callia is 'plug and play' with Linux hosts, and no software installation is required. 3.
Part 4 Callia hardware
Prism Sound Callia 4 Operation Manual Revision 1.01 Callia hardware This section describes in detail the capabilities of the Callia hardware. 4.
Prism Sound Callia Operation Manual Revision 1.01 well as conventional DSD streams at multiples of 44.1kHz. These are indicated by the '48k' LED in combination with the 'DSD' (and possibly 'x2') LEDs. Line volume control The line volume control allows Callia to drive a power amplifier directly, without the need for an external volume control. The halo of LEDs around the knob shows the volume setting.
Prism Sound Callia 4.2 Operation Manual Revision 1.01 Rear panel Callia's rear panel contains all of the input and output connections, except for the headphone jack which is on the front panel. From left to right (viewed from rear): · 6A IEC inlet (regional power cord supplied): adjacent is the mains fuse holder. · USB 2.0 device port for connection to a host computer (cable supplied). · DIP switches: to customise some aspects of Callia's operation. See the DIP switch functions section below.
Prism Sound Callia Operation Manual Revision 1.
Prism Sound Callia Operation Manual Revision 1.01 S/PDIF inputs Callia can also be connected to both optical (TOSLINK) and RCA S/PDIF sources, and supports PCM at standard sample rates between 44.1kHz and 192kHz, and wordlengths up to 24 bits. DSD, formatted as DSD-over-PCM (DoP) is supported at a bit-rates of 2.8224MHz (DSD64), plus 48kHz-multiple DSD64. Note that professional AES3 and AES3-id digital carrier formats will also work using an appropriate adapter at the RCA input.
Part 5 Callia software and firmware
Prism Sound Callia 5 Operation Manual Revision 1.01 Callia software and firmware Callia's software content comprises two separate parts. In the terminology of this manual, the 'firmware' is the part which resides, stored in flash memory, within the Callia unit itself and controls all of the analogue, digital, conversion and DSP functionality at a low level. The 'software' resides on any Windows PC or Mac which will stream audio to Callia. Callia is a class-compliant USB Audio Device Class 2.
Part 6 Technical topics
Prism Sound Callia 6 Operation Manual Revision 1.01 Technical topics The following sections contain detailed discussions of various relevant technical issues. The content of these sections is not required to operate Callia, but is provided as background information. 6.1 Stability and latency Ever since audio found its way inside the computer, problems concerning issues of stability and latency have arisen.
Prism Sound Callia Operation Manual Revision 1.01 latency. That feature is not available or necessary for use with Callia. Callia should be able to play audio files and streams reliably even at high bit rates (such as DSD128 or 384kHz 32 bit PCM) simply by ensuring that adequate buffering is chosen within the player application.
Prism Sound Callia Operation Manual Revision 1.01 Analysis of sampling jitter Analysis of sampling jitter (small variations in the sampling intervals of an A/D or D/A converter) shows that it produces a similar effect to phase modulation, where distortion components appear as ‘ sidebands’ spaced away from the frequency of a converted tone by the frequency of the jitter itself. These components get louder as the amount of jitter increases, but also as the frequency of the converted tone increases.
Prism Sound Callia Operation Manual Revision 1.01 Listening experience In practice, it seems that the benefits of careful clock design are very apparent in listening tests. On the other hand, it can sometimes be difficult to expose the shortcomings of converters with poor clocks, because these units often have other analogue problems whose severity might obscure jitter-related effects.
Prism Sound Callia Operation Manual Revision 1.01 mass-interconnection the system grounds using heavy gauge cable so as to minimize the hum voltage resulting from the current. Obviously many items of analogue audio equipment only have unbalanced connections; this is especially true of consumer equipment, which is often used for monitoring even in professional studios. If you must use unbalanced connections, keep them as short as possible and use good-quality cables with substantial screens.
Prism Sound Callia Operation Manual Revision 1.01 In summary · Use good-quality cables with reputable connectors; · Use balanced connections where possible; if you must use unbalanced connections, keep them short; · Ensure that signals passing between equipment do so at as high a level as is practical; · If switching interference is heard, try to identify the source equipment by unplugging things one by one.
Prism Sound Callia Operation Manual Revision 1.01 Conversion quality issues But surely the sound quality of a digital audio setup can't depend on the choice of digital audio cabling, so long as all the data bits get through? Sadly, and familiarly, though - it can. Because in many cases the audio data stream is used to pass the sampling clock as well as the audio data between equipment.
Prism Sound Callia 6.5 Operation Manual Revision 1.01 DSD (Direct Stream Digital) conversion DSD was conceived in an age when monolithic sigma-delta converters were relatively new. The quantisers in the converter chips of the day were one-bit and ran at 64x the eventual PCM rate ('64fs'); their digital decimation and interpolation filters were real-estate-limited and so had very non-ideal behavior in terms of flatness and stop-band attenuation - as well as being confined to PCM rates below 50kHz.
Prism Sound Callia Operation Manual Revision 1.01 (worse) back to analogue, so maybe we shouldn't be prissy about the DAC chip. Having said this, there are a few rigorously-produced minimalist DSD recordings which haven't been processed at all, but one wonders whether the ADC had a one-bit 64fs front end: if not, we're back to DSD via PCM, if so, performance was presumably limited.
Part 7 About Prism Sound
Prism Sound Callia 7 Operation Manual Revision 1.01 About Prism Sound Prism Sound was founded in 1987, the brainchild of two engineers: Graham Boswell and Ian Dennis. They had first met when working on the ground-breaking DSP program at world-renowned audio mixing desk manufacturer Rupert Neve & Company in Cambridge, England. In its early years, Prism Sound was a specialist Research & Development consultancy, designing digital audio equipment for a number of leading hi-fi and pro-audio manufacturers.
Part 8 Specifications
Prism Sound Callia 8 Operation Manual Revision 1.01 Specifications Front Panel Input selection LEDs: Indicate auto/manual select mode and current input: optical S/PDIF, RCA S/PDIF or USB Indicate sample rate: 44.1, 48, 88.2, 96, 176.4, 192, 352.8*, 384* kHz, Sample rate / format DSD64 DSD128* (also indicates whether PCM word-length is > 16 bits or LEDs: > 24 bits) Controls the volume at the analogue line outputs when enabled, halo Line volume control: indication 6.
Prism Sound Callia Headphone Output Output amplitude: Output impedance: Total harmonic distortion: THD+n: Dynamic range: Gain accuracy: LF roll-off: HF roll-off: Operation Manual Revision 1.01 0dBFS=18.0dBu (HiZ), 14.45dBu (MedZ), 8.45dBu (LoZ) at top of potentiometer 4R -104dB (0.00045%, -0.1dBFS) -103dB (0.00050%, -0.1dBFS) 113dB (-60dBFS) ±0.05dB at top of potentiometer -0.05dB at 6Hz; -3dB at 1.45Hz fs=44.1kHz: -0.05dB at 20.3kHz; -3dB at 22.0kHz fs=48kHz: -0.05dB at 21.1kHz; -3dB at 23.
Prism Sound Callia Operation Manual Revision 1.01 Performance Plots Except where otherwise stated, audio performance data are typical, RMS, unweighted, 20Hz..20kHz figures, measured at 997Hz, using fs=96kHz at the XLR outputs. In keeping with our policy of continual development, specifications are subject to amendment without notice. E&OE. All Trade Marks acknowledged. © 2016 Prism Media Products Ltd 1.
Index -EEarthing -A- -F- Analogue interconnections 23 Analogue line outputs 14, 15 ASIO 10, 18 Auto source selection 12 Features 6 Firmware 18 Updates 18 Version 18 Front panel 12 Fuse locations and ratings -BBalanced outputs Buffer size 20 23, 25 -G- 15 Getting started 7 Glitches 20 Grounding 23, 25 -CCallia features 6 CleverClox, Prism Sound Clocking 21 Connections 7, 14 Core Audio 10, 18 Customising 14 21 -DDecimation 27 Digital interconnections 25 DIP switches 14 Direct Stream Digital 12, 1
-LLatency 20 LED brightness 12 Line outputs 14 Line volume control 12, 14, 15 Linux 8, 10 -MMac 10, 18 Manual source selection 12 -O- 12 Specifications 32 Stability 20 Standby mode 12 Standby/source button 12 Switched-mode power supplies System requirements 8 Technical topics TOSLINK 15 Input 14 15 -PPC 10 Performance features Prism Sound 30 CleverClox 21 Source selection Auto 12 Manual 12 27 23, 25 -T- OS X 10, 18 Versions 8, 10 Outputs Sigma-delta modulator Software 7, 18 Installation 10 Upd