In audio PA system it is common to use 70V or 100V speaker.
I have some experience in systems which are implemented by a standard amplifier developed for the required audio power in conjunction with a trasformer increase the output voltage and adapts the impedance.
It looks like there are implementations which explot a calss-D amplifier with a half-bridge or full-bridge output stage which drive the 100V line without the need of the transformer. I suppose a big issue with this approach should be the EMI. In any case it looks impossible (or very difficult, I was not able) to find a reference design for a system like this.
I wonder wheter there is a reason for which this approach is not pursued. Any consideration will be very appreciated. Thank you.
