JAMO 250 Speaker User Manual


 
Electronics
The important things on subwoofer amplifiers are the ability to deliver high
power – especially peak burst are important to reproduce e.g. an explosion or a
bass drum with full fidelity. This has to be done with a minimum of distortion
and a very tight control of the woofer.
Due to the nature of a normal class AB amplifier we would need to have a very
big power supply since only approx 60% of the power is turned into sound –
the rest is turned into heat. Consequently the heatsinks of these amplifiers
would also have to be enormous in order to cool the amplifiers sufficiently.
On the other hand a class AB amplifier has some excellent qualities – such as
musicality, low distortion and high damping factor.
So, if we could combine these qualities with the efficiency of a Class D amplifier
it would be ideal . . .
Consequently, the development team turned to a specialized technology that
matched our demands perfectly: High power output with high efficiency while
maintaining musicality, low distortion and tight control of the woofer. A
patented technology called BASH®.
The key idea of the BASH technology is based on a continually variable supply
voltage which tends to zero when there is no input signal and reaches its
highest level when the amplification requires power. This supply voltage is
continuously variable but always lower than that of an AB class amplifier and
thus a much higher efficiency is achieved.
The outstanding energy efficiency (85%) achieved by this technology, allows
very high output power, without heating up the amplifier and thus elimination
of the need for excessive heat sinks.
The power supply itself uses a high speed D class unit in order to constantly
supply the amplifier with the appropriate power.
Due to its voltage switching capability a BASH amplifier plays louder than a
conventional amplifier of comparable RMS power. Simply by not being a
voltage limited amplifier it has tremendous dynamic power capability.
Controls & Features
All the subwoofers features volume-, variable phase- and variable cut off
frequency controls to make sure that the sound from the subwoofers can be
adjusted to blend in seamlessly with the sound from the rest of the speakers.
SUB 650 also features a 12V trigger input, so it can be turned on and off from a
A/V receiver/controller that has a 12V output, ensuring that the subwoofer
always will be active when the A/V receiver/controller is turned on.