2 X Mean Well DRP-480-24 trans make into 48V AC

I assume you mean 48V DC?

You really can't. The power supply you list puts out 24V DC, most likely with the -V (Ground) tied to the chassis. If you connect these in series like stacking batteries, one of the supply cabinets will be sitting at +24V DC with respect to everything else around it that is at ground, a very bad condition. A short circuit would be really bad. You need to purchase one of the 48V power bricks that typically power TI 3255 designs. There are many to choose from.
 
According to mean well, it should go. But whether the TI 3255 likes this is unknown.

https://forum.digikey.com/t/connecting-mean-well-power-supplies-in-series/19294

That is not a good solution. It still needs the serial diodes (which lower the voltage by ~1,4V) and requires also capacitors to buffer the power supply. That also does not prevent any issue with a stray connection and the power supplies will probably try to out-compensate each other in a high current situation or strong phase shift. That solution is meant for a quite constant power demand, which an amplifier is not. I would not recommend it, even if it would work to a degree but might result in a voltage surge or drop out without notice.