Philips DA1102 - Manual (Page 17)

DA11 Operation
13
2.) Connect the main output of the DA11 directly to the input of a power amp or powered monitors
and use the Volume control of the DA11 to adjust the speaker volume.
PLEASE NOTE: When operating the DA11 connected directly to a power amp or powered
monitors, it is important to reduce the VOLUME of the DA11 to a very low setting BEFORE
turning the AC power of the power amp or monitors “ON!”
Because the DA11 is capable of driving professional level balanced inputs as well as consumer
level unbalanced (RCA) inputs, some care is needed when using the DA11 with unbalanced
consumer HiFi equipment. Although exceeding the absolute maximum input level is not likely to
cause damage, it will reduce the quality of the listening experience. It is recommended that the
first time you use the DA11 feeding equipment with a volume control, you start with the DA11 at a
very low setting, and raise the volume on the preamp or receiver to a level you would use to listen
to other inputs (Phono or FM radio, for example). Switch to the input that the DA11 is feeding,
and raise the Volume setting of the DA11 until the acoustic volume is the same as other sources.
Matching the acoustic level between sources will almost certainly mean you are not exceeding
the input rating of your equipment!
There is wide variation in the absolute maximum input level that HiFi equipment is capable of
accepting without distortion. When this level is exceeded, the music program can be distorted
regardless of the volume setting of the HiFi equipment because the distortion can be caused
before the volume control. This could also occur when feeding a power amp or powered monitors
directly, especially if the input level control of the power amp/monitors is turned “down” very low.
It would be harder to detect in this situation, because the corresponding acoustic volume would
typically be very loud.
- Most consumer equipment with RCA inputs are designed to operate with an absolute maximum
input level of 2V rms (which is 5.6 V peak-to-peak). When operating in unbalanced configuration,
the VOLUME setting on the DA11 that corresponds to this level is “46.” It is recommended to
check the specifications and confirm this corresponds to the absolute maximum input rating of
your equipment according to the manufacturer! If it does not, you should determine the correct
setting of the DA11 that is the absolute maximum setting for your system. Please see the section
titled “Determining the Correct DA11 Volume Setting for other input ratings” (below).
- For professional equipment with balanced inputs, a VOLUME setting of 56 corresponds to
+24dBu. Some professional equipment has a maximum input rating of +18 dBu, which
corresponds to the VOLUME setting of “50” on the DA11 for balanced operation and “56” for
unbalanced operation.
In cases where the DA11 is feeding a consumer receiver or preamp, once the absolute maximum
level has been established, the actual level used for typical listening may be lower than this value.
As a rule, if you switch between analog sources on the receiver or preamp and there is a large
difference in volume between other sources and the DA11, it is probably better to lower the
VOLUME setting of the DA11 below the absolute maximum level if it is much louder than other
sources. It will probably take some experimenting with different music program to establish a
good “working volume” with your system. There is a possibility that the optimum DA11 level
setting will still result in the DA11 being slightly louder than other sources. It is also recommended
that you not exceed the absolute maximum level, even with music program that has large
variations in level, because a loud peak could occur that would cause distortion.
In most cases, lowering the volume setting on the DA11 will degrade the signal quality less than
lowering the volume control on the receiver below a setting which is “normal” for other analog
sources (phono, FM broadcast, etc.). The digitally controlled analog level circuitry of the DA11
degrades the signal less than typical “knob” potentiometer volume controls on consumer
equipment, particularly at lower level settings.