Technical information

the Never Connected power supply is perhaps the best design available, offering a
high degree of isolation from the ‘dirty’ mains. Switch mode power supplies are
used in some audio applications but they tend to inject noise into the signal path
and are not favoured by most audio product designers.
PSP Pit Signal Processing - a digital watermark feature used on SA-CD.
Pre-amplifier Nominally this boosts a low level signal to a level suitable for
delivering to a power amplifier, but in these days of fairly high output source
components (such as CD players), their main function is to provide a volume
control and switch between different sources. Some pre-amplifiers may
incorporate such things as loudness and tone controls and mute buttons. Some
pre-amplifiers also incorporate a phono preamplifier which boosts the low level
signal (say 5 to 100 millivolts) of a phono cartridge's output and applies RIAA
equalization, but these tend to be of low quality.
Q, R
Quantization The numerical value assigned to a particular analogue voltage input
at an instant of time in an analogue to digital converter, or the process of making
such an assignment. The range of numerical values available, and consequently
the accuracy of the assignment, depends on the bit depth of the PCM system
employed.
Quantization noise A form of harmonic distortion produced in all digital systems.
Low level signals do not use all the bits available in the digital system (that's why
they are low level signals!) Consequently they operate as though the digital system
has a low bit depth (say, an eight bit system or even four). This increases their
harmonic distortion. By its nature, harmonic distortion generated by digital
systems tends to give relatively high levels of odd-order harmonics, which are far
more irritating than the even order harmonics to which analogue systems tend.
This is routinely addressed by adding dither to digital signals.
Red book See RBCD.
RBCD Red Book CD - the original Compact Disc Digital Audio standard that defines
regular audio CDs.
RCA plug/socket Also known as a ‘phono’ connector in the UK. Perhaps the
most common audio and video connection standard. They are used for standard
audio connections, as well as composite video, component video (three of them in
this case) and digital connections.