Conrad-Johnson D/A-3 User manual

Thankyou forselectingtheD/A-3asthedigital/analogconverterforyour
audio system. It is ideally suited for use in combination with conrad-
johnson’s DR-1 CD transport to form a compact disc playback system
capable of extracting all the detail and dynamics of the best digital
recordings.
At conrad-johnson, we expect our products to be a source of satisfaction
and of pride to their owners for many years to come. Accordingly, circuit
designs, parts and materials for all conrad-johnson products are se-
lected with a view to maintaining optimal performance over the years.
Our reputation for producing among the industry’s most reliable compo-
nents is a natural consequence of this engineering approach.
Although the D/A-3 has been designed so that its basic opertation is
intuitively apparent, it has a number of sophisticated features which are
fully explained in this manual. Please take a few minutes to read the
manual to better understand the features and capabilities of your D/A-3.
In closing, we’d like to welcome you to the family of conrad-johnson
owners. We want you to enjoy your conrad-johnson product to the
fullest. To this end, our staff stands ready to answer any questions you
may have about the function and application of your D/A-3, and to
provide any needed service both during, and after the warranty period.
Our goal is to heighten your enjoyment of recorded music.
D/A-3 Owner’s Manual 1

Limited Warranty For Conrad-Johnson Components
conrad-johnson design, inc. will provide service under warranty to the
original owner on products sold new in the United States for the lesser
periodof threeyears fromthedateofpurchasebythe originalpurchaser,
or five years from the date of shipment to the authorized conrad-johnson
dealer. During the warranty period, conrad-johnson will repair defective
units without charge for labor or parts (with the exception of vacuum
tubes and batteries).
Exclusions. The following are not covered under this warranty:
a) Units which have been damaged by misuse, abuse, or accident.
b) Units which have been modified, altered, or improperly repaired by
anyone not specifically authorized by conrad-johnson design, inc.
c) Units not purchased from an authorized conrad-johnson dealer in the
United States for use in the United States.
d) Normal wear.
e) Incidental or consequential damages are not covered under this
warranty. Some states do not allow the exclusion of incidental or
consequential damages, so this exclusion may not apply to you.
Obtaining Warranty Service:To obtain warranty service, the unit must
be shipped, along with evidence of purchase, in factory packing to
conrad-johnson design (or designated service center) with freight and
insuranceprepaidbytheowner. Afterrepair,theunitwillbereturnedwith
freight and insurance prepaid by conrad-johnson design to any destina-
tion in the United States.
Allimplied warranties,including merchantabilityandfitnessforaparticu-
lar purpose are limited in duration to the duration of this express
warranty. Some states do not allow limitations on the duration of implied
warranties so the above limitations may not apply to you.
This warranty gives you specific legal rights and you may also have
other rights which vary from state to state.
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
warranty service for products originally purchased outside their country.
Conrad-Johnson will provide warranty service for products outside the
D/A-3 Owner’s Manual 2

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
If your conrad-johnson audio component requires service, repack it
using the original box and packing material and ship to the Service
Department address above. Boxes and packing materials can be ob-
tainedfrom ourservice departmentforanominalcharge,ifyou nolonger
have yours. Include with the unit a note describing the problem you are
having in as much detail as possible. It is especially important for our
technician to know if the problem is intermittent. 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.
D/A-3 Owner’s Manual 3

Installation
Because the D/A-3 dissipates very little heat, ventilation is not an
important consideration, allowing greater flexibility for custom or built-in
installations.Ofcourse, reasonablejudgementmustbe exercisedtosee
that the D/A-3 does not obstruct ventilation required by amplifiers or
otherequipmentin the system.Theunit may bemountedeither horizon-
tally or vertically.
All D/A-3s sold in the United States are configured for operation on a
60Hz ac power line producing between 108 and 126 volts. Export
versions of the D/A-3 will have the correct operating voltage and fre-
quency clearly marked on the back panel of the unit, near the ac power
cord. In all cases, the actual line voltage should be within + 5/- 10% of
the nominal rated voltage.
Electromagnetic Interference (EMI)
Considerablecare hasbeen takeninthedesignoftheD/A-3 tominimize
it’s susceptibility to radio frequency interference and other forms of EMI.
Choice of materials, physical layout, grounding practice, and power
supply design have all been specified with a view to reducing the impact
of electromagnetic fields on the performance of this unit. At the same
time, however, our primary goal is the accurate reproduction of recorded
music in the normal home environment, and we have elected not to
compromise this objective by the application of heavy-handed RFI
filters, or by using grounding practices that reduce RFI at the expense
of degraded audio performance. We find that the approach we have
taken has worked extremely well, resulting in only rare instances of EMI
problems which could be treated locally as needed, rather than compro-
mising the performance of our product in the 99.9% of installations
where EMI is not a problem.
CareininstallationcanoftenavoidEMIinducedproblems.Thefollowing
practices should generally be observed in any application, and will be
especially important where EMI may be a problem.
Interconnect cables should be kept as short as possible (3 meters or
less), and shielded cable should be used (cable which has two center
conductors, and a separate external shield connected at only one end).
D/A-3 Owner’s Manual 4

Physical location and cable "dress" can be an important factor in mini-
mizing hum pickup. The installation should situate the D/A-3 away from
the preamplifier, and power (ac mains) cords should be dressed to
remain at least 4" (100mm) away from the output cable.
CONNECTION
The D/A-3 provides three separate digital inputs (two coaxial, and one
optical) and a coaxial digital output. Connect your digital sources (CD
transport, Laser Disc Player, digital recorder) to any of these inputs, and
a digital tape recorder to the digital output.
Digital Inputs
COAXIAL 1, COAXIAL 2: Direct coupled coaxial inputs with phono
connectors.
OPTICAL: TOSLINK optical connector. The TOSLINK connector is
supplied with a plug to prevent dust from accumulating on the lens of the
receiver. Leave this plug in place whenever this input is unused.
The D/A-3 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 phono connector is provided to send the digital
signal out to another digital device (normally a digital tape recorder).
ANALOG OUTPUTS: These are the audio outputs, to be connected to
a line-level input on your preamplifier.
D/A-3 Owner’s Manual 5

CONTROLS
coax one, coax two, optical: This selector switch is used to choose a
digital input for listening. The selected digital signal is also sent to the
digital output. On units with the optional ST glass optical input fitted,
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 of phase shift (inverted) in the absolute phase of the audio
output signal to compensate for phase inverted recordings.
D/A-3 Owner’s Manual 6

Getting The Most From Your D/A-3
In a system of commensurate high quality components, the conrad-
johnson D/A-3 offers an extraordinary level of sophistication and refine-
ment in music reproduction. To get the best performance out of any
audio system, there are 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
unnaturalalternativeof a negativetransient(an initial fallinair pressure).
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 either preserves the phase of the
incoming signal, and is said to be phase correct, or inverts the phase
and is said to be phase inverting. It is unimportant whether an individual
component is phase correct or phase inverting, as long as the system
as a whole is phase correct. This will be the case if 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, and use the phase invert switch on the D/A-2b to correct for
phase incorrect recordings.
The Importance Of Wires
Interconnect and speaker wires are an important element in your stereo
system. Interconnects are available which will permit a reference quality
system to blossom and fulfill its promise of musical reality. Others will
strangle the system to the point where it becomes little better than
D/A-3 Owner’s Manual 7

average. To complicate matters, our experience suggests that the
choice of interconnects will be system dependent - those that are top
ranked on one system may be a poor choice for a different system.
Consult your conrad-johnson dealer for recommendations for your spe-
cific system.
Performance Tip
Warmup theD/A-3before listening:The sonicperformanceof theD/A-3
improvesnoticeablyas the unit warmsup.Themidrange becomes more
lucid, the highs smoother, and the soundstage expands. The warm up
period can be expected to last for several days. For this reason, it is
recommended that the D/A-3 be left on at all times.
Questions: If you have questions about the installation or function of
your D/A-3 do not hesitate to call Customer Service at [phone].
D/A-3 Owner’s Manual 8

SPECIFICATIONS
Output @ 0 dB: 1.0V
Frequency Response: 20Hz to 20kHz +0,- 1.0 dB
Hum and noise: 92dB below 1.0V output
Output impedance: less than 200 ohms
Mechanical:
Dimensions: : 14.375 "D x 19"W x 3.315"H
Net Weight: 14 lbs.
Fuses
The D/A-3 has a fuse on the ac power line to protect it’s
transformer. Failure of this fuse is a symptom of a more serious
problem, and a competent service technician should be consulted.
In no event should the fuse be replaced with a value or type
different than that originally supplied. The correct fuse is:
If configured for 100 or 120V operation: 1/2 amp, fast blow
If configured for 220 or 240V operation: 1/4 amp, fast blow
D/A-3 Owner’s Manual 9