Curious to know if you are considering building a digital amp?
Some of my switching amplifier thoughts:
I've been playing with switching amplifiers for years. Basically the difference between an analog amplifier and a switching amplifier is in the way you modulate power to the loudspeakers.
Switchers are more efficient than analog but the trade-off is that they can be (read: are) very noisy.
Switchers have been used for years in mid-fi applications with moderate success and in the past three years or so have started to show up in some high-end audio products.
Switchers can sound open and airy because they are fast, but if an analog amp is well designed and fast it can sound open and airy as well.
Today I see some nice switchers out there from a few companies that have put a lot of thought and effort (R&D) into their products. Improvements being made by these companies are in the modulation techniques. It requires a big commitment to develop new technology and I applaud the few companies that are blazing the trail.
Even though switchers today are better than ever, IRD has no plans to build a high-end switching amplifier any time soon. Our next amplifier will be the MB-250 which is an analog design.
I am an expert switching power supply desiner (a close cousin to switching amplifiers) but I don't have the expertise today to design an exceptional high-end audio switcher.
IRD has a 50W switcher in R&D for one of our U.S. customers mid-fi applications which will give us some practical experience with switch modulation, controlling the excessive noise, and passing the strict FCC regulations. Perhaps after we get past this project, if we like what we did, we might consider taking a more advanced step towards high-end audio.