Applied Research and Technology (ART) DIO Owner's Manual

The ART

DI/O

TABLE OF CONTENTS

Introduction ......................................................................................... 2

Installation ........................................................................................... 3

AC Power Hookup ............................................................................. 3

Audio Connections ............................................................................ 3

Safety Precautions ............................................................................ 3

Controls and Indicators .......................................................................4

Input Gain Control ............................................................................. 4

Sample Rate Switch .......................................................................... 4

Sample Rate LED Indicators ............................................................. 5

Signal Level LED Indicators ............................................................... 5

Tube Warmth Control ........................................................................ 6

Power LED Indicator ......................................................................... 6

Connections ........................................................................................ 7

¼” Input Jacks.................................................................................... 8

¼” Output Jacks ................................................................................ 8

S/PDIF Output Jack ........................................................................... 8

S/PDIF Input Jack ............................................................................. 8

Power Jack ....................................................................................... 9

Operation ........................................................................................... 10

Warranty Information ........................................................................ 14

Service ............................................................................................... 15

DI/O Specifications ............................................................................ 16

INTRODUCTION

Designed to help ease the transition to the digital world, the DI/O offers
high-resolution stereo 24-bit A/D-D/A conversion at switchable sample rates
from 44.1 to 96kHz. In external sync mode, the DI/O’s intelligent
synchronization allows for automatic sync to outboard equipment from
22kHz to 100kHz.

The DI/O can be used in a wide variety of applications including recording,
project, and home studios. Let the DI/O be the interface for your “classic”
analog signal processing gear in an all-digital production environment. It’s
the perfect interface for any computer-based recording system and gets the
A/D-D/A conversion process out of the noisy digital environment.

You can use the DI/O as your instrument’s direct-to-digital interface, thanks
to its high input impedance. Upgrade the A/D-D/As on your DAT machine or
older digital I/O equipment with the DI/O’s high-resolution converters. Get
more dynamic range on new samples and overdubs. You can loop thru the
DI/O to add “analog” warmth and musicality to an existing digital track.

The latest refinements in ART’s award winning tube pre-amp design are
integrated on the front end, before the A/D converter, for analog gain and
dynamic range control. At the clean setting, the tube circuitry is virtually
bypassed and the A/D sees a “straight wire with gain” signal. As you
increase the control the signal goes from ultra clean and transparent, thru
silky, to smooth, to warm, to fat. At the warm end the tube becomes the
dominant gain element, enhancing lower and mid level signals and soft
limiting peaks and overshoots before they hit the A/D.

FEATURES:

• 2 channels of A/D and 2 channels of D/A conversion

• High Resolution 24-bit, 96kHz, 128x oversampling converter

• 44.1, 48, 88.2, 96kHz switch-selectable sample rates

• Intelligently syncs to external sample rates from 22kHz to 100kHz

• S/PDIF Coaxial, Digital inputs and outputs, RCA type jacks

• Hand-selected 12AX7A dual triode tube

• Fully variable tube character from transparent to warm

• ¼” High impedance stereo inputs and ¼” line level stereo outputs

• Variable input gain from 0dB(unity) to +20dB

INSTALLATION

The DI/O may be used in a wide variety of applications and
environments. Self-contained in an all-steel enclosure, the DI/O is
designed for continuous professional use. Because the unit is compact
and lightweight, mounting location is not critical. However, for greater
reliability we recommend that you not place the DI/O on top of power
amps or other sources of heat. The tube circuitry needs about a minute
to “warm up” from a cold power up.

AC POWER HOOKUP

The DI/O has an external power supply designed to operate at 115
VAC @ 50 to 60 Hz. Units manufactured for use outside the United
States of America have been modified to comply with the required
electrical specifications. Only use the adapter that came with the
DI/O. If the adapter becomes lost or damaged; contact ART Customer
Service for replacement. If you need to purchase one locally, just make
sure that you specify 9 Volt AC output (not DC), at 800 ma.

AUDIO CONNECTIONS

Audio connections to and from the DI/O are unbalanced ¼” (Tip = Hot
(+), Sleeve = Ground). We recommend that you turn down the INPUT
GAIN control whenever changing connections to the inputs.

SAFETY PRECAUTIONS

Warning: To avoid the risk of shock or fire, do not expose this unit to

moisture. Refer all servicing to qualified personnel. Do not remove the
metal cover; there are no user-serviceable parts inside. You should
only use the power adapter that came with this unit or one obtained
from ART’s Customer Service Department.

CONTROLS & INDICATORS

INPUT GAIN CONTROL

The Input Gain control allows you to add gain to the input signal before
the tube and A/D converter. Turn the control clockwise to increase gain
and counterclockwise to decrease gain. At the fully counterclockwise
position (0dB), incoming signals are passed at unity gain to the A/D
converter. At this setting the inputs can handle “hot” signals, up to
+20dBu, before clipping the A/D. When the Input Gain control is at the
fully clockwise position (+20dB), the incoming signal is boosted in level
before the A/D. This allows you to increase low level signal sources by
up to 20dB, to maximize the input dynamic range of the A/D. In normal
operation you would increase the Input Gain control until the red “0dB”
LED just lights on signal peaks.

SAMPLE RATE SWITCH

Use the Sample Rate Switch to select the desired sample rate. Each
time you press the switch, it increments through the available choices
while the LEDs beside it show the current state. The DI/O remembers
the sample rate setting and powers up at the same sample rate that it
was in before power was removed. This allows you to, in many
applications, set the sample rate for your system once and leave it.

SAMPLE RATE LED INDICATORS

The Sample Rate LED Indicators show the current sample rate that the
DI/O’s A/D and D/A are operating at. When set to one of the internally
generated sample rates (44.1, 48, 88.2, or 96kHz), the DI/O provides
the Master clock source from its internal crystal clock.

When set to the External Sync position, the DI/O will use the S/PDIF In
jack as the source of its Master clock. It will synchronize to, and track,
sample rates from 22kHz to 100kHz. The green (Ext.) LED indicator
will light solid as long as the source has valid audio sync. It will flash if
the data on the S/PDIF input jack does not contain valid audio data.
When this occurs the D/A will mute its audio outputs to prevent
unwanted noise. The A/D will still digitize audio and track the external
Master clock.

SIGNAL LEVEL LED INDICATORS

The three Signal Level LED Indicators are designed to help set levels
before the A/D, to maximize your dynamic range.

The green (-20dB) LED comes on when the signal at the A/D is 20dB
below full-scale digital clipping on signal peaks. It just starts to come on
when the average signal is around 30dB below clipping. You should
increase your input signal level, or the DI/O’s Input Gain until this light
is on solid whenever there is signal for best performance.

The red (0dB) LED comes on when the signal at the A/D is 3dB away
from full-scale clipping. With most audio material, you would increase
the input signal or Input Gain until this light just starts to come on
during signal peaks.

The yellow (Warm) LED comes on whenever the tube is adding
warmth or character to the signal. This is a function of both the input
signal level and the Tube Warmth control.