Special Features
Stewart Audio’s new “Compact Series” Power Amplifiers utilizes the latest
in Digital Audio Technology. The new, all Digital DA Series Power Amplifiers
were developed by Stewart Audio’s Digital Audio Team and represent the
pinnacle of Stewart Audio technology and design.
Please take a few moments to read through this section of the manual,
which provides an overview of the features that makes this amplifier
unique.
How is the DA-770-2 Amplifier different from other Amplifiers?
Advances in semiconductor technology have enabled a digital
revolution and spawned products that entertain us and im-
prove our productivity. From CD players to digital high defini-
tion TV; from the PC, through optical networks, to the Inter-
net and wireless telephones, digital electronics and signal
processing has been the core enabling technology that brings
the performance and cost for mass adoption.
Stewart Audio Inc. has used its Digital Power Processing tech-
nology to create a new breed of digital audio Power Amplifi-
ers. This new class of digital amplifiers provide the audio fi-
delity of traditional linear (Class-A/B) amplifiers with more
than twice the power efficiency of these devices. This leads to
higher levels of integration and smaller packages at the semi-
conductor level. At the system level, these advantages re-
duce the size of power supplies and heat sinks and signifi-
cantly reduce the heat management challenges of today's
modern Power Amplifiers. Power conversion efficiencies of
80% to more than 90% is typical of this design.
While pulse width modulated (PWM) switching amplifiers
(Class-D) can also achieve similar power advantages, none
have been able to do so without a significant compromise in
audio fidelity. Hence the new Stewart Audio digital amplifier –
A new standard in audio performance and power efficiency.
Customers no longer have to choose between sonic fidelity or
efficiency. Both can now be achieved with Stewart Audio’s
new Digital Technology.
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Trouble shooting
If you experience difficulty in operating your new DA-
70 Series amplifier, Chances are good that you will be
able to remedy the problem yourself using standard
troubleshooting techniques and the suggestions offered
in the troubleshooting table on the next page.
When wiring cables it is imperative that all connections
be made cleanly with no stray wire strands to short ter-
minals. Make sure the wire clamp screws are tight. For
proper connection all wire should be stripped to bare
approximately ¼ inch of wire. Make sure that the con-
nector set screw seats on copper, not insulation.
Keep in mind that other components in the system can
cause problems which may appear to be caused by the
amplifier; systematic troubleshooting will allow you to
isolate the source of difficulty.
If you fail to correct the problem by following the out-
lined chart on the next page,
do not attempt
to open
or repair the unit yourself.
Please contact Stewart Audio at 209.588.8111 to
obtain a Return Authorization (RA) Number and
shipping instructions
. Once an RA Number is ob-
tained, return the unit to Stewart Audio at the address
indicated on the RA Form. Refer to the enclosed War-
ranty information for Terms and Conditions of War-
ranty.
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