Conrad-johnson design D/A-1 User manual

Congratulations on your purchase of the conrad-johnson D/A-1 digital
processor. You have acquired one of the finest pieces of music repro-
duction equipment available today. The D/A-1 has been designed with
the goal of faithfully reproducing the dynamics, tonalities, textures and
ambienceofalivemusicalperformance.Thedesignandmaterialshave
been carefully selected to yield years of unvarying excellence.
Please take a few minutes to read this manual so that you will better
understand the features and capabilities of your D/A-1.
DA1 Owner’s Manual 1

LIMITED WARRANTY FOR CONRAD-JOHNSON AUDIO
COMPONENTS
1. conrad-johnson design, inc. warrants that conrad-johnson brand
audio components purchased from an authorized conrad-johnson
dealer in the United States for use in the United States will be free of
defects in materials and workmanship for the lesser period of three
years from the date of purchase by the original purchaser, or five years
from the date of shipment to the authorized conrad- johnson dealer.
2. During the warranty period, conrad-johnson will repair defective
units without charge for labor or parts (with the exception of the vacuum
tubes) subject to the following conditions:
a) The unit must not have been altered or damaged through misuse,
abuse, negligence, accident, or improper operation;
b) The purchaser must provide evidence of purchase at the time
service is requested;
c) All repairs must be undertaken at the factory or other service center
designated by conrad-johnson design, inc. Units submitted for
warranty repair must be shipped in factory packing to conrad-johnson
design or its designated service center, freight and insurance prepaid
by the owner, and will be returned to the owner, freight and insurance to
any destination in the United States prepaid by conrad-johnson design.
d) Normal wear and maintenance are not covered by this warranty.
3. Where permitted by law, conrad-johnson design’s liability shall be
limited to that set forth in this warranty. No other warranty of any kind,
expressed or implied, is made by conrad- johnson design, inc., and all
implied warranties, including merchantability and fitness for a particular
"purpose", which exceed the obligations and time limits set forth herein
are hereby disclaimed. conrad-johnson design, inc. shall not be liable
for incidental or consequential damages. Some states do not allow the
exclusion or limitation of incidental or consequential damages, or limita-
tions on how long an implied warranty lasts, so the above limitations or
exclusions may not apply to you.
4. This warranty gives you specific legal rights, and you may also have
other rights which vary from state to state.
5. Conrad-Johnson products purchased outside the United States are
covered by warranty terms of the importing distributor in the country in
which the product was originally purchased, which may differ from the
terms set out herein. Importing distributors are not obligated to provide
DA1 Owner’s Manual 2

warranty service for products originally purchased outside their country.
Conrad-Johnson will provide warranty service for products outside the
United States, but the customer must pay all shipping, handling and
customs costs both to and from our Service Department.
Questions about this warranty should be addressed to:
Service Department
conrad-johnson design, inc.
2733 Merrilee Drive
Fairfax, VA 22031
The Service Department can also be reached by phone at 703-698-
8581, or by fax at 703-560-5360
SERVICE
In the event your conrad-johnson audio component requires service,
repack it with the original packing material and ship to the Service
Department address above. If you do not have the original packing
material, replacements are available from conrad-johnson design for a
nominal charge. Be sure to include a copy of your sales receipt from the
original purchase, along with a note explaining the problem you are
having in as much detail as possible. If the problem is intermittent,
please indicate. If you want an estimate of cost for out of warranty
service, be sure to request it in this note. Be aware that requesting an
estimate will delay service to your unit as we will have to contact you for
your approval before commencing service.
REGISTERING THE WARRANTY
Please return the enclosed card to the factory within 30 days of pur-
chase to register the warranty.
DA1 Owner’s Manual 3

INSTALLATION
The D/A-1 should be mounted horizontally on a flat hard surface.
Vertical installation is not recommended.
To minimize hum pickup, keep the unit well away from the power
amplifier, and route power cords away from input cables.
The D/A-1 requires an ac power line providing between 108 and 125
volts at 50 to 60 Hz. Alternatively, the D/A-1 is optionally available for
operation on 100, 220, or 240 volt power lines.
CONNECTION
The D/A-1 provides three separate digital inputs (two coaxial, and one
optical) and a coaxial digital output. Connect your digital sources (CD
transport, Laser Disc Player, DCC recorder) to any of these inputs, and
a DCC or other digital tape recorder to the digital output.
Digital Inputs
Coaxial 1: Transformer coupled coaxial input with BNC connector
Coaxial 2: Direct coupled coaxial input with phono connector
Optical: TOSLINK optical connector. The TOSLINK connector is sup-
plied with a plug to prevent dust from accumlating on the lens of the
receiver. Leave this plug in place whenever this input is unused.
The D/A-1 is optionally available with an additional ST glass optical
connector. This option includes a back panel mounted toggle switch to
select between the two optical connectors.
Outputs
Digital Output: A BNC connector is provided to send the digital signal
out to another digital device (normally a DCC recorder).
DA1 Owner’s Manual 4

Analog Outputs: These are the audio outputs, to be connected to a
line-level input on your preamplifier.
CONTROLS
INPUT: coax one, coax two, optical: This selector switch is used to
choose a digital input for listening. The selected digital signal is also
senttothedigitaloutput.Onunits withtheoptionalSTglass opticalinput
fitted, the selecting "optical" on the input selector will connect the optical
input that has been selected by the back panel toggle switch.
Phase: This switch allows selection of 0degrees "phase correct" and
180 degrees "inverted" of phase shift in the absolute phase of the audio
output signal to compensate for phase incorrect recordings.
Because the discrete analogue audio circuits require a long warm-up
time before they reach optimal performance, the D/A-1 is intended to
remain on at all times, and no on/off switch is provided.
DA1 Owner’s Manual 5

GETTING THE MOST FROM YOUR D/A-1
The conrad-johnson D/A-1 offers a remarkable level of sophistication
and refinement in music reproduction, but it cannot transform an inferior
stereo system. Only high quality amplifiers and loudspeaker systems
will be capable of fully revealing the capabilities of this precision instru-
ment.
Given a system of high quality components, there remain a number of
important details which must be attended to.
ABSOLUTE PHASE
Musical notes are heard through the ear’s response to waves of alter-
nating rise and fall of air pressure. Musical transients are almost exclu-
sively positive: that is, the initial effect is a rise in pressure. The ear is
capable of distinguishing these positive transients from the musically
unnatural alternative of a negative transient (an initial fall in air pres-
sure). In terms of your stereo system, these transients are created by
your loudspeakers. If the speakers respond to musical transients by first
moving out, they are creating a rise in pressure, and the system is said
to be "phase correct". If they respond by moving in, they create a fall in
pressure and the system is said to be phase inverting.
Each component in the stereo system is either phase correct or phase
inverting (including the source and speakers-these are normally phase
correct). It is of no consequence if an individual component is phase
inverting, as long as the system as a whole is phase correct. This will be
the case as long as the number of phase inversions is even (or zero). A
system with an odd number of phase inversions can be corrected by
adding one more inversion by reversing the positive and negative
speaker leads.
We recommend that you connect your system for correct absolute
phase,andusethe phaseinvertswitchontheD/A-1tocorrectforphase
incorrect recordings.
DA1 Owner’s Manual 6

THE IMPORTANCE OF WIRES
Both digital and analog interconnect wires are an important element in
the performance of your digital playback system. Interconnects are
availablewhich will permitareference quality systemtofulfill its promise
of musical reality, whereas others will fall far short. Consult your conrad-
johnson dealer for recommendations for your specific system.
Questions: If you have questions about the installation or function of
your D/A-1 do not hesitate to call Customer Service at [phone].
DA1 Owner’s Manual 7

D/A-1 SPECIFICATIONS
Output @ 0 dB: 1.0V
Frequency Response: 5Hz to 20kHz +0,- .5 dB
Hum and noise: 92dB below 1.0V output
Ouput impedance: less than 200 ohms
Mechanical:
Dimensions: : 19"W x 3.315"H x 14.375"D
Net Weight: 16 lbs.
DA1 Owner’s Manual 8