I have long been familiar with the practical difference between "valve watts" and "transistor watts". i.e. My hundred watt all valve head sounds louder than my 700 watt transistor power amp. But recently I was told that from a practical perspective there are different kinds of transistor watts. In particular, switching mode power supplies (as used in the modern light weight power amps such as the QSC PLX) were not well suited to bass use because they had trouble supplying currents approaching DC at lower frequencies. Can any of the more technical members advise whether there is any inherent limitation in switching mode power supplies that make them less suitable for bass applications than "conventional" designs with big transformers / capacitors?