Infrasonic QUARTET, Manual

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1. Introduction
INFRASONIC QUARTET is a multi-purpose pro audio interface card using stable PCI bus
technology. PCI interface cards run faster and are more stable than Hot-plug systems such
as USB and FireWire. QUARTET is suitable for providing high quality, multi-function, sound
editing for your home studio and at a good price.
QUARTET has better performing analog I/Os than other cards in its class. It supports 192
kHz ADC sample-rate with Full 24-bit recording. The high-quality AD/DA converter has
115dB S/N ratio and the high-end components in the analog circuit improve dynamic range
by 10dB.
Other features include MIC preamp, direct instrument input, MIDI I/O, coaxial I/O, word
clock I/O and dual headphone amplifiers. QUARTET will satisfy a user as professional gear in
feature, performance and convenience.
1.1. The cutting edge technology
US-PSB class I (Ultra Stable Power Supply Block)
The QUARTET is equipped with ‘US-PSB class I’ OP-AMP based discrete circuits instead of
a general regulator type IC.
US-PSB reduces output noise as well as reducing power noise by more than 10dB.
Mass storage capacitors and protection circuits effectively deal with electronic shock and
noise. It can be monitored in detail by the powerful drivers and OP-AMP circuitry.
It results a very stable power flow.
In addition, it has the function of slowly rising voltage, called “Slow slope ON”. This
protects monitor speakers and headphones from being damaged by ‘pop-noise’ when you
turn on your PC.
IS (InfraSonic) Microphone Preamplifier
IS MIC Preamplifier - a low noise transistor buffer, high quality microphone preamplifier
(E.I.N: Equivalent input noise -127dBu).
Not only is the value of E.I.N 20dB lower, but its quality of CMRR and frequency response
is better than other similar grade products.
It delivers professional recording studio grade audio quality.
PAD / GAIN jumpers allow the usage of many microphone types (from the condenser
microphones to low leveled dynamic microphones).
Like a professional MIC preamplifier, QUARTET supports the Low-cut function and +48V
phantom power.
Noise Guard Bracket
Generally, a lot of high frequency digital noise exists inside of a computer, especially if
you have more PCI cards close to one another.
Noise Guard Bracket is designed to protect QUARTET from electronic noise that the
computer and other PCI/video cards generate.