Gilderfluke&Co Sd-25 Audio Repeaters w/Amplifier - Manual

Sd-25 Configuration & Installation
Before the Sd-25 can be used, you will need to load your SoundFiles onto a MMC/Sd flash card, attach a power
supply, speakers, and (optionally) a switch to start the Sd-25. Selecting the operating mode will tell the Sd-25 how you
would like your SoundFiles to be played.
MMC/Sd Card:
Any 3.3 volt Multi Media Card (MMC) or Secure
Digital (Sd) flash memory card
can be used with the Sd-25.
Starting with version 1.16 of
the Sd-25 firmware, Sd HC
cards are also supported.
These will be available with
c a p a c i t i e s u p t o 2 0 4 8
GBytes. As of this writing, Sd
cards are available in sizes
up to eight GBytes. These
hold about 2000 typical Mp3
songs for about four days of
continuous audio playback.
The Sd-25 supports up to
255 SoundFiles in most op-
erating modes. Some modes
support up to 32,767 Sound-
Files.
The flash card should be
formatted ʻFATʼ or ʻFAT32ʼ (it
will probably come that
way). The order in which
the SoundFiles are placed
onto the card is the order
in which the Sd-25 will
play them. You can load
Mp3 and .wav files onto
the card using a flash card
writer attached to a PC or
Mac.
For the Sd-25s to recog-
nize a SoundFile, its FileName must start with an
alphanumeric character, and it must have the exten-
sion of either ʻ.wavʼ or ʻ.Mp3ʼ. If a SoundFile meets
these criteria, the Sd-25 will attempt to play it. If the
Sd-25 canʼt play a SoundFile for any reason, it will
give up after about three seconds.
The Sd-25 will play just about all Mp3 or .wav file
formats. Mp3 bit rates up through 320 Kb/second
are supported. .wav files of up to 48 Kbytes/second
and sixteen bit are supported. If a file does not play,
it is most often caused by a large (more than 2
MBytes) ʻid3ʼ tag at its front. These typically
hold the album cover artwork for files down-
loaded from iTunes and similar sources.
Since a Sd-25 canʼt use album artwork, it
simply takes up additional storage space,
delays the time it takes a SoundFile
to start playing, and (in the worst
case), will keep a SoundFile from
playing at all. Most audio programs
(including iTunes) have an option to
delete ʻid3ʼ tags.
Speaker Outputs:
The Sd-25ʼs amplifier is a ʻClass-Dʼ
design. Its efficiency is near 90%. If
you feed 50 Watts of 24 vdc into the
Sd-25ʼs amplifier, you will get al-
most 50 Watts into your speakers.
ʻLinearʼ amplifiers have only about
20% efficiency. Fully 80% of
the power you put into
t h e m g o e s i n t o t h e
heatsink as waste heat. A
50 Watt linear amplifier
would only feed 10 Watts of
power into your speakers,
and 40 Watts into the
heatsink. This makes the
Sd-25ʼs amplifier roughly
equivalent to what would be
a 200 Watt linear amplifier!
If you are going to run your speakers at high SPLs,
you will need to select speakers that can handle at
least a 125 to 150 Watts or more of continuous
power. Speakers smaller than this may clip or be
damaged if run at too high an output power level
from the Sd-25.
The amplifier outputs from the Sd-25 can be used
with speakers of four to eight ohms impedance. As
with any amplifier, you can series/parallel a number
Gilderfluke & Co.• 205 South Flower Street • Burbank, California 91502 • 818/840-9484 • 800/776-5972 • fax 818/840-9485
page 1 of 16 • © February 11, 2014 Gilderfluke & Co. DCM
Audio Repeater
Sd-25
Gilderfluke & Company
Burbank, California
B
Left Right
12–24 vdc
Power
Power
12–24
vdc
A
R
un
ni
ng
S
ta
tu
s
Level
Sd-
Left
Line In Level Line In Level Level
Sd-
Right
Trigger
Inputs
Speakers
(4! to 8!)
Mixer
Right
Mixer
Left
Power Supply
12 to 24 vdc
Optional Line
Level Source
Switch 'B'
Switch 'A'