8
1- When starting up the amplifier and until ends the Stand-by time needed to stabilize the
internal voltages.
2- Because there is a shortcircuit at the amplifier output. The PAM models are equipped
with a protection system that does not interfere the sound quality. They can supply loads as low as
0.3
Ω
for short periods of time and up to 150 A peak current. In case of a permanent shortcircuit,
the protections will disconnect the amplifier in less than 70msec. The protections also become
active when there exist an excessive high frequency clipping, thus protecting the treble
loudspeakers.
3- If the amplifier is supplying DC signal or very low frequencies that could damage the
loudspeaker. The protections detect frequencies under 4Hz and DC voltages greater than 2Vdc.
If the indicators are permanently lit, this is a symptom of missfunction and it should be
investigated.
The protection circuit can get active when the amplifiers operates under circumstances
such as very low load impedances or high level transitory input signals. The Autoreset system will
restart the amplifier after a few seconds. If the protections are activated 4 times in less than 5
minutes then the amplifier will stop and a manual Reset will be needed by means of the POWER
switch. If the problem is still there, please consult our Technical Services.
4.3.c) Clipping indicators 'CLIP' (4)
They will shine when the output signal is 0.3dB under the true clipping. This system takes
into account the possible changes of the mains supply and always gives a true measure
independently of the mains voltage. It is usual that the CLIP indicators shine following the bass
frequencies when the amplifier operates at high power levels. Take care that the CLIP indicators
are not permanently lit.
4.3.d) 'MONO BRIDGED' indicator (2)
It shines when the back panel OP.MODE switch is placed on the BRIDGED position (option
not available on PAM2000/2600 models).
4.3.e) Thermal protection indicator 'THERMAL' (6)
It shines when the cooling tunnel temperature reaches 90ºC. The amplifier will
automatically restart when the temperature lessens to 80ºC.
4.4. Operation at 2
Ω
Operation at 2
Ω
considerabily reduces the sound quality and the system efficiency; e.g.,
the loss on the loudspeaker cable reduces the Damping Factor by a 76% because of operating at
2
Ω
instead of 8
Ω
.
Almost all the amplifiers in the market base their operation at 2
Ω
on the use of destructive
protections to keep the components safe, with the penalty of sound quality. Also, and for both
technological and power supply reasons, the power gain involved in operation at 2
Ω
instead of 4
Ω
is usually very low.
The 4th Generation SPM ECLER amplifiers are able to operate at 2
Ω
keeping its
philosophy of non destructive protections and supply all the available power ( about 70% more
than at 4
Ω
) with the only limitation of the Thermal protection., wich would only get active after a
