The baffless main audio system is based on current drive amplifiers. They work almost 10 years now very well, but they need to be improved. The requirements for the new design are:

• Very high performance galvanically isolated I2S input DAC should be integrated on amplifier board. 

      This simplifies future multiway systems. Just add and multiply concept. Simple plug and play.

       DAC integration on board improves performance. No possibility for ground loops. No additional wiring.

• Current drive amplifier should be floating load design

      This means not to use improved howland current pump design previously used. Main reason is the

       possibility of circuit linearisation with low current low voltage precision circuit. Power circuit can be quite bad and simple. Low          power circuit will take care of that.

• Power circuit should be simple bullet proof design

      This means it has to be powerful and reliable with minimum parts involved. Power supply connection, standby power and

      isolated digital in connection.

• Amplifier should be cold design

     It should be kind B class design. AB class design for high voltage amp makes much heat even for modest biasing. This is a

      big loss of efficiency in there. Depending on listening level AB class biasing can contribute to more energy loss than actual

       music signal energy loss. High quality music has high crest factor and average listening is not so high in level and not so long in

       duration. Switching amps would be even more efficient, but EMC compatibility and pollution with noise of circuits near by would

       be a very big development challenge for a very high performance for now, so not used.

• Auto power on feature should be added

      Amplifier should not be controlled by another system, it should be independent from other systems. It knows when to power

      on and when to shut down by himself.

• Amplifier has to be current drive all the way except at resonant frequency of the driver

      It is because voltage drive has better THD at resonance at least for tested high quality drivers and provides electrical damping

      in case it needed. This can be done in DSP also.

• Amplifier has to be high performance first, price will be good anyway as no alternatives are existing