Operation Manual
12. Rear panel
E SERIES Operation Manual rev 2.1.0
13
The following features are located on the rear panel of the E Series:
1 Attenuators – Individual attenuation for the two amplier channels. Range is 0 dB to -innity. The 12 o’clock
position indicates -10 dB attenuation. The sensitivity for the amplier is 4 dBu when the attenuator is at 0 dB and
14 dBu when the attenuator is at -10 dB.
2 SIG – The green indicator will be lit whenever the input signal is above the signal present threshold. Indication
is the same as the front panel indicator is currently playing.
3 High-pass / Full-range – Selects either at down to 2 Hz or High Pass lter at 50 Hz.
70 V / Lo-Z – This switch denes the settings for the Rail Sensing Limiter
TM
(RSL).
• 70 V should be used for constant voltage systems and if full rated power into 8 or 16 ohms loads is required.
• Lo-Z should be used for rated power into 2 or 4 ohms loads. It can also be used to limit the maximum power
into 8 or 16 ohms loads.
If more than half the total power is required for one channel driving an impedance of 4 ohms or higher, then the
70 V setting can be used for this channel.
Operation into 2 ohms is not recommended when using 70 V mode.
4 Output – The detachable output block connectors are designed and approved for 41 Arms (much more than
the maximum capacity of the ampliers). Cables up to 8 mm
2
(8 AWG) may be used. Please ensure that all leads
are securely attached inside the connector to avoid short circuits. Also verify that the loudspeakers are connected
with the same polarity to avoid low frequency cancellation losses.
5 GPIO – The amplier comes with an Automatic Power On / Down APO / APD scheme triggered by the program
material, so in many applications external power control is not necessary. If remote power control is desired, then
an external relay can be connected to the GPI control port.
12.2. Input Signal Present Threshold (SPT)
As shipped the default input signal threshold is set at -56 dBu (-60 dB relative to 4 dBu, which is the sensitivity).
This threshold applies to the input signal present indicators on the front and rear panels as well as to the
Auto Power On / Down (APO / APD).
If this threshold is deemed too high or low, it can be trimmed by pressing and holding the power button for two
full seconds. The amplier will then sample the input signal and set the SPT threshold 6 dB above the sampled
noise oor. The procedure should be done with all “front end” equipment on, but with no active signal input. Please
ensure that no audio is accidently passed during this calibration as that can lead to a high SPT that in turn could
generate and store an undesirable threshold for APD.
A typical scenario for changing the default would be when the source has a very high noise oor. In this case,
adjusting the threshold prevents the noise from triggering a false APO. The calibration procedure detects the higher
noise oor and sets the SPT threshold at 6 dB above it.