I normally drive my Klipsch La Scalas with a variety of SET amplifiers, but this week, the Bay Area is having a “heat dome” with temperatures even in San Francisco hitting 90 degrees! I am running my La Scalas with a Lyngdorf 2170 PWM digital amplifier with RoomPerfect room correction. It works quite well. Not a SET sound, of course, but very transparent and musical given the right recordings. It won’t sugarcoat a bad recording, but with well-recorded material, it is a nice cool running one box HiFi setup (the 2170 has a USB input, and decodes all codecs including DSD).
One advantage of true PWM digital amplifiers like the Lyngdorf is that there is no volume control in the circuit at all (digital or analog). When you reduce the volume, you are adjusting the power supply voltage. The bitstream is converted into a pulse-width modulated signal at a constant level (using the Equibit method), and the sound is kept in the digital realm till the last passive RC network, which converts the very high bitrate PWM bitstream directly into analog. If you want to do digital amplification, this sounds like the way to do it. With RoomPerfect as the cherry on the cake, this really does feel like a true 21st century solution to Hi Fi.
Of course, with my 105 dB efficient La Scalas, my volume setting is like -50 dB (!), but like I said, with PWM digital,
there’s no digital truncation like you get in a normal DAC that throws bits away. I wish Lyngdorf would release a high efficiency model with something IIke 5-10 watts, but that’s not going to happen!