Controls And Functions; Protection Devices - dB Technologies HPA Serie Bedienungsanleitung

1 CONTROLS AND FUNCTIONS

1.1 Frontal Panel
1. MAINS SWITCH
This switch powers up and powers down the amplifier by cutting off both power
phases.
2. VOLUME CONTROLS
These controls are used to regulate the volume of the two channels separately.
In the MONO and BRIDGE configuration, only use the CH1 and set CH2 to the
minimum.
3. PROTECTION INDICATORS - "PROTECTION"
These red LED indicates i.e. direct current, radio disturbances or subsonic
frequencies or also when an overcurrent situation occurs.
Such a situation is usually caused by a short circuit on the appliance outputs or by a
speaker impedance that is too low.
4. PEAK INDICATORS - LIMITER"
These yellow LED indicators tell you that the maximum amplification level has been
reached, with relevant limitation if LIMITER is active. The continuous illumination of
these indicators denotes an excessive input signal.
5. LEVEL INDICATORS
These green LED indicators progressively lighting up show output levels from -
30dB to 0dB.
6. AIR INTAKE GRILLES
Air is sucked in through these grilles to cool the amplifier. Do not obstruct the grilles.
Clean the air filters when necessary.
7. BRIDGE CONFIGURATION INDICATOR "BRIDGE" (HPA3100L only)
The yellow LED indicator lighting up means that the amplifier is configurated for
"BRIDGE" mode use, it is selected from dedicated switch on rear panel.
8. POWER INDICATOR - "POWER" (HPA3100L only)
The green LED indicator lighting up indicates that the amplifier is operative.
1.2 Rear Panel
1. POWER CABLE SOCKET
For connecting the power cable supplied with the amplifer.
2. SPEAKON CONNECTOR (CH1 output)
Use this connector to take the CH1 amplified signal and the bridge configuration
signal.
3. SPEAKON CONNECTOR (CH2 output)
Use this connector to take the CH2 amplified signal.
4. CONFIGURATION MODE SELECTOR - "MODE"
Use this three-position selector to choose the required configuration mode (MONO-
STEREO-BRIDGE).
5. INPUT SENSITIVITY SELECTOR - " GAIN SENSITIVITY"
Use this three-position selector to choose the input sensitivity (26dB-32dB-1,4V), it
is indipendent for every channel.
Selecting 26dB or 32dB the input gain is the same for all models.
Selecting 1,4V obtain the same input sensitivity for all models.
6. LIMITER SELECTOR - "LIMITER"
Use this two-position switch to activate or deactivate the integrated limiter, it is
indipendent on every channel.
7. XLR CONNECTOR Input CH1
Use this XLR connector to pilot CH1 channel with balanced or unbalanced signal.
Use only CH1 for the MONO and BRIDGE configurations.
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8. XLR CONNECTOR Link CH1
This XLR connector is in parallel connection to INPUT CH 1 (7), it is possible to use
to send audio signal to other amplifiers.
9. XLR CONNECTOR Input CH2
Use this XLR connector to pilot CH2 channel with balanced or unbalanced signal.
10. XLR CONNECTOR Link CH2
This XLR connector is in parallel connection to INPUT CH2 (9), it is possible to use
to send audio signal to other active loudspeaker, recorder or amplifiers.
11. AIR INTAKE GRILLES
Air is sucked in through these grilles to cool the amplifier. Do not obstruct the grilles.
Clean the air filters when necessary.

2. PROTECTION DEVICES

2.1 Thermal protection devices
If the amplifier overheats (temperature >105°C), the amplifier will protect itself by setting
the input audio signal to "mute" mode until normal operating conditions are restored.
This is shown by the PROTECT red LED indicator on front panel .
All models are fitted with a thermal protection device for the toroidal transformer,
ensuring safety even in the most severe operating conditions. The activation of this
protection feature indicates machine utilisation at the extreme limits of the amp's
specifications and cutout will occur as before.
Subsequent power-up and restoration of all the functions is automatic and occurs when
the normal working temperature has been restored. The protection device intervention
time might be very long since the core of the transformer will take a long time to dissipate
the heat that has accumulated.
2.2 DC/RFI protection devices
All the amplifier models are provided with relays on the audio outputs. These devices
protect the speakers in the case of direct current, radio disturbances and subsonic
frequencies and they also perform an anti-bump function when the amplifier is powered
up.
The tripping of this cutout is indicated by the lighting up of the red indicator on the front
panel of the amplifier, marked PROTECT.
Normal operations are restored automatically when the interference is eliminated.
2.3 Short-circuit protection devices
The amplifiers feature output short circuit cutouts. Such cutout put in "mute" state the
input signal, this condition is interrupted by signal restoring attempts (about every 3-4
seconds).
Normal amplifier operation is restored automatically once the short-circuit has been
corrected.
This cutout also trips in the event of the appliance supplying too much current (load
impedance too low).
2.4 Limiter (selectable)
The models are fitted with two limiter circuits ensuring correct operation with input
signals up to +10dB from the correct sensitivity value. In addition to optimising the
amplifier's performance, these devices also protect the speakers against distorted
signals that might damage them.
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