This is a huge step in the right direction getting rid of another point of noise (the smp), with the added lift of future higher switching frequency/filters and the benefits it brings, would spell the end of all linear amps. And Srajan's tubes below.
Practically all supplies are switchers. So called linear are very primitive -switching at 120Hz when voltage is the highest, creating a lot of high frequency noise. Current is drawn in narrow spikes of high amplitude. SMPS on the other hand, when done right, is far better in many respects. It is quiet, switching at zero voltage/zero current. It operates at high frequency that is easy to filter out (much easier than 120Hz ripple) and is line and load regulated (vs. unregulated linear supply). It has fast response to load demands - vs. slower response caused by inductance of huge electrolytic caps. It tolerates DC on the mains (It even operates from DC). Rowland switched completely to SMPS using them for class AB amps as well as for preamps (to lower the noise). Benchmark improved S/N ratio by 10dB by replacing linear supply in their DAC with SMPS. New class AB amp from Benchmark ABH2 also utilizes SMPS resulting in 132dB dynamic range.
Why then, designers still use linear supplies with huge transformers and capacitors? For two reasons: First, it is very difficult to design good switcher. Second, they follow market demand - many people believe that it has to be "linear" and heavy.
