How Do Digital Amplifiers Clip?


I will be moving the speakers from the current "A" system to a secondary system where the current solid state amplifier is underpowered. I am fond of the old speakers and do not want "kill" them as the ads used to say by clipping the amp. This got me wondering how digital amplifiers clip and how an underpowered digital amplifier affects the speakers when over driven?
zmrs13
This got me wondering how digital amplifiers clip and how an underpowered digital amplifier affects the speakers when over driven?
a digital power amplifier is a switching amplifier (a cousin to the omni-present switch-mode power supply in our computers). So, the output is toggling between plus/minus supply rail & ground. This switching waveform is filtered (usually by a LC filter or many LC filters, each of which is/are a 2-pole filter) to produce the average signal, which is the music signal amplified. As long as the input signal is within the power amplification limits the output signal switches with a duty cycle well below 100% & well above 0%. Once you start over-driving the digital power amplifier, the digital switching output starts switching with a duty cycle approaching 100%, which basically means that the switching output stays a long time at plus/minus supply rail for a much longer time than it stays at ground voltage. The average/filtered version of such a waveform is a (near) DC voltage at the output.
So, at clipping levels, the digital power amplifier will output high levels of DC that will be fed to your vintage speakers & THAT (the DC) will be the death of them. The tweeter usually has a high-pass network which means that it has a series capacitor that will block DC but the woofer (& even the midrange) does/do not have a series capacitor so DC will be fed directly to the driver & it'll damage very quickly, if not immediately.
hope that this helps.....
It's a good question. If my Class D amps have clipped, I have not heard it yet. Avoiding clipping like death is a big reason I went for 500w/ch Icepower amps. I like my music loud and my large OHM speakers are not particularly efficient (87db or so I believe). I've heard a lot of amps both SS and tube clip over the years. If the BC ref1000ms have ever clipped, I am not aware of it. Nothing I throw at them can seem to make them even break a sweat.
I have the bel cantos too. They have a soft clipping feature to smooth the waveform and cut output slightly as clipping approaches. I believe that feature is built into the B and O ICE module. Like mapman above I never run out of steam. I just keep turning it up and the soundstage gets bigger, deeper and wider.