
Musikhaus Thomann e. K.
Treppendorf 30
96138 Burgebrach
Germany
Telephone: +49 (0) 9546 9223-0
E-mail: info@thomann.de
Internet: www.thomann.de
13.08.2012

Table of contents
1 General notes............................................................................................................................................... 4
2 Safety instructions..................................................................................................................................... 7
3 Features....................................................................................................................................................... 12
4 Installation and starting up................................................................................................................ 13
4.1 Pin assignment.................................................................................................................................. 14
5 Connections and operating elements........................................................................................... 18
6 Power consumption............................................................................................................................... 23
7 Technical specifications....................................................................................................................... 24
8 Protecting the environment.............................................................................................................. 26
Table of contents
D4-500
3

1
General notes
This user manual contains important information on safe operation of the device. Read and
follow all safety notes and all instructions. Save this manual for future reference. Make sure
that it is available to all persons using this device. If you sell the device to other users, be sure
that they also receive this manual.
Our products are subject to a process of continuous development. We therefore reserve the
right to make changes without notice.
This section provides an overview of the symbols and signal words used in this user manual.Symbols and signal words
General notes
digital power amplifier
4

Signal word Meaning
DANGER! This combination of symbol and signal word
indicates an immediate dangerous situation
that will result in death or serious injury if it is
not avoided.
CAUTION! This combination of symbol and signal word
indicates a possible dangerous situation that
can result in minor injury if it is not avoided.
NOTICE! This combination of symbol and signal word
indicates a possible dangerous situation that
can result in material and environmental
damage if it is not avoided.
Warning signs Type of danger
Warning – high-voltage.
General notes
D4-500
5

Warning signs Type of danger
Warning – danger zone.
General notes
digital power amplifier
6

2
Safety instructions
This device amplifies electric audio frequency signals to operate passive speakers. Use the
device only as described in this user manual. Any other use or use under other operating con‐
ditions is considered to be improper and may result in personal injury or property damage. No
liability will be assumed for damages resulting from improper use.
This device may be used only by persons with sufficient physical, sensorial, and intellectual
abilities and having corresponding knowledge and experience. Other persons may use this
device only if they are supervised or instructed by a person who is responsible for their safety.
DANGER!
Danger for children
Ensure that plastic bags, packaging, etc. are disposed of properly and are not
within reach of babies and young children. Choking hazard!
Ensure that children do not detach any small parts (e.g. knobs or the like) from
the unit. They could swallow the pieces and choke!
Never let children unattended use electrical devices.
Intended use
Safety
Safety instructions
D4-500
7

DANGER!
Electric shock caused by high voltages inside
Within the device there are areas where high voltages may be present. Never
remove any covers.
There are no user-serviceable parts inside.
DANGER!
Electric shock caused by short-circuit
Always use proper ready-made insulated mains cabling (power cord) with a pro‐
tective contact plug. Do not modify the mains cable or the plug. Failure to do so
could result in electric shock/death or fire. If in doubt, seek advice from a regis‐
tered electrician.
Safety instructions
digital power amplifier
8

CAUTION!
Possible hearing damage
The device can produce volume levels that may cause temporary or permanent
hearing impairment. Over an extended period of time, even levels that seem to
be uncritical can cause hearing damage.
Decrease the volume level immediately if you experience ringing in your ears or
hearing impairment. If this is not possible, keep a greater distance or use suffi‐
cient ear protectors.
NOTICE!
Risk of fire
Do not block areas of ventilation. Do not install the device near any direct heat
source. Keep the device away from naked flames.
Safety instructions
D4-500
9

NOTICE!
Operating conditions
This device has been designed for indoor use only. To prevent damage, never
expose the device to any liquid or moisture. Avoid direct sunlight, heavy dirt, and
strong vibrations.
NOTICE!
Power supply
Before connecting the device, ensure that the input voltage (AC outlet) matches
the voltage rating of the device and that the AC outlet is protected by a residual
current circuit breaker. Failure to do so could result in damage to the device and
possibly injure the user.
Unplug the device before electrical storms occur and when it is unused for long
periods of time to reduce the risk of electric shock or fire.
Safety instructions
digital power amplifier
10

NOTICE!
Magnetic fields
The device generates strong magnetic fields that can interfere with the function
of poorly shielded devices. The strongest magnetic fields are directly above and
below the power amplifier. Therefore, never place sensitive devices such as preamplifiers, radio transmission systems, or tape decks directly above or below the
power amplifier. When installing the power amplifier into a rack, you should place
it in the lowest position, and further equipment such as pre-amplifiers in the
highest position.
Safety instructions
D4-500
11

3
Features
n Output power
– 4 × 500 W @ 4 W
– 4 × 250 W @ 8 W
n 4 inputs, 4 outputs
n Frequency response 20 Hz to 20 kHz
n 19" rackable (1 RU, installation depth 240 mm)
Features
digital power amplifier
12

4
Installation and starting up
Unpack and check carefully there is no transportation damage before using the unit. Keep the
equipment packaging. To fully protect the device against vibration, dust and moisture during
transportation or storage use the original packaging or your own packaging material suitable
for transport or storage, respectively.
Establish all connections as long as the unit is switched off. Use the shortest possible highquality cables for all connections.
Installation and starting up
D4-500
13

4.1
Pin assignment
You can use XLR and 1/4" plugs with balanced or unbalanced wiring. In the following, we will
give you an overview of the various options. Drawings and tables indicate the XLR pin assign‐
ment.
Balanced wiring:
1 Ground, shielding
2 Positive signal (+)
3 Negative signal (–)
XLR connections for signal
inputs
Installation and starting up
digital power amplifier
14

Unbalanced wiring:
1 Ground, shielding
2 Signal
3 Bridged to pin 1
Drawings and tables indicate the pin assignment of 1/4" phone plugs to be used.
Unbalanced wiring of a TS plug:
1 Signal
2 Ground, shielding
1/4" phone sockets for signal
inputs
Installation and starting up
D4-500
15

Unbalanced wiring of a TRS plug:
1 Signal
2, 3 Ground, shielding
Balanced wiring of a TRS plug:
1 Positive signal (+)
2 Negative signal (–)
3 Ground, shielding
Installation and starting up
digital power amplifier
16

The drawing alongside shows the pin assignment of the lockable NL4 mounting connectors.NL4 mounting connectors
Installation and starting up
D4-500
17

5
Connections and operating elements
Front panel
Connections and operating elements
digital power amplifier
18

1 ON | OFF
Main switch to turn the device on or off.
2 LED Power
This LED indicates, that the unit is operational and lights up constantly as soon as the device is switched on.
3 LEDs –10 dB and –20 dB
These LEDs indicate the intensity of the input signal (–10 dB or –20 dB). If none of the LEDs lights up, increase the
signal level with the controls CH-A to CH-D and -if required- check the wiring.
If these LEDs are lit without an input signal is present, there is an error. In this case, disconnect the speakers from the
power amplifier and turn the controls for the input gain of channels CH-A to CH-D down to minimum. If the LEDs still
light up, the device must be inspected by an authorized service centre.
4 LEDs Clip
Overload indicator for channels CH-A to CH-D. These LEDs light up when the distortion of the output signal increases
1 %.
Connections and operating elements
D4-500
19

5 LEDs Fault
Error indication for channels CH-A to CH-D. These LEDs light up when one of the protective circuits triggers (see
Ä
Chapter 7 ‘Technical specifications’ on page 24).
When turning the device on, the LEDs light up for three seconds. During this time, there is no signal present at the
output yet . Once the LEDs turn off, the device is operational.
6 LEDs Thermal
Over temperature indicator for the channels CH-A to CH-D. These LEDs light up when the respective heat sink
exceeds a certain temperature.
When turning the device on, the LEDs light up for three seconds. During this time, there is no signal present at the
output yet . Once the LEDs turn off, the device is operational.
7 CH-A …-D
Input gain control for the channels CH-A to CH-D.
Connections and operating elements
digital power amplifier
20

Rear panel
Connections and operating elements
D4-500
21

8 IEC chassis connector with fuse holder for operating voltage supply.
9 INPUT CH-A …-D
Lockable XLR / 1/4" mounting combo connectors for signal inputs.
10 OUTPUT CH-A …-D
Lockable NL4 mounting connectors for signal outputs.
11 Pushbutton Stereo | Parallel | Bridge
Toggle switch for the operating modes ‘Stereo’ (all channels operate independently of each other), ‘Parallel’ (the
inputs of a channel pair are interconnected) and ‘Bridge’ (two channels are interconnected to form one channel with
double output).
12 Pushbutton Lift | Ground
Use the Ground / Lift switch to separate the connection between the earth pin of the device and the signal ground in
the unit. This prevents ground loops (position ‘Lift’ [switch is not pressed]: no connection. Position ‘Ground’ [switch is
pressed]: earth pin and signal ground are electrically connected).
Connections and operating elements
digital power amplifier
22

6
Power consumption
The following table shows the typical current consumption depending on the output power
level (RMS value A
RMS
).
Load 1/8 power
(pink noise)
1/3 power
(pink noise)
Full power
(sine wave)
8 W (× 4)
130 W / 1.3 A 190 W / 1.9 A 640 W / 4.2 A
4 W (× 4)
180 W / 1.6 A 420 W / 3.1 A 1200 W / 7.4 A
8 W bridged (× 2)
190 W / 1.6 A 430 W / 3.2 A 1200 W / 7.2 A
Power consumption
D4-500
23

7
Technical specifications
Rated output power @ 8 W
4 × 250 W (THD = 1 %, 1 kHz)
Rated output power @ 4 W
4 × 500 W (THD = 1 %, 1 kHz)
Max. voltage swing (RMS) 35 V (THD = 1 %, 1 kHz)
Slew rate (1 kHz)
26 V/ms
THD
< 0.1 %, typical
DIM 30
< 0.1 % (3.15 kHz, 15 kHz)
Crosstalk
> 75 dB (ref. 1 kHz, 10 % rated power)
Frequency response 20 Hz … 20 kHz (–2 dB) (–1 dB, ref. 1 kHz)
Input impedance
20 kW (balanced)
10 kW (unbalanced)
Input sensitivity 1 V
rms
(for rated power @ 1 kHz)
Damping factor
> 500 (100 Hz / 1 kHz, 4 W)
Technical specifications
digital power amplifier
24

Signal-to-noise ratio 107 dB (A-weighted)
Protective circuits VHF, direct voltage, temperature, short circuit, Undervoltage, overcurrent, lim‐
iter
Operating voltage supply
AC 230 V , 50/60 Hz
Power consumption
see Ä Chapter 6 ‘Power consumption’ on page 23
Dimensions 1 RU in a 19" rack, installation depth 240 mm
Weight 4.6 kg
Technical specifications
D4-500
25

8
Protecting the environment
For the transport and protective packaging, environmentally friendly materials have been
chosen that can be supplied to normal recycling.
Ensure that plastic bags, packaging, etc. are properly disposed of.
Do not just dispose of these materials with your normal household waste, but make sure that
they are collected for recycling. Please follow the notes and markings on the packaging.
This device is subject to the European directive 2002/96/EC.
Do not dispose of the device with your normal household waste.
Dispose of this device through an approved waste disposal firm or through your local waste
facility. When discarding the device, comply with the rules and regulations that apply in your
country. If in doubt, consult your local waste disposal facility.
Disposal of the packaging mate‐
rial
Disposal of your old device
Protecting the environment
digital power amplifier
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Musikhaus Thomann e.K. · Treppendorf 30 · 96138 Burgebrach · Germany · www.thomann.de