15-Feb-2016, 01:44
(This post was last modified: 15-Feb-2016, 02:23 by Joseph Jones.)
or Le120: True or false? All analog inputs pass through ADC, are digitized.
Independent confirmation is helpful in this case. I'd prefer my strain gauge phono stay in the analog domain rather than pass through ADC. Has any pro or amateur review described audible distortion in the ADC?
If true, I suppose I can adapt my thinking to it.
Comment at THIS review: "...is actually class A and class D run in parallel all the time and at all levels. Class A defines the sound character and provides voltage while the class D stage deliver current and ‘drive’. As far as I’ve understood, the class A amp also outputs a correction signal (created by the powerful DSP) to cancel the switching noise inherent to most class D..."
Peter Walker of Quad invents "Current Dumping" amp:
"...Peter put this principle into practice using two amplifiers per channel instead of one. The first stage ‘error’ amplifier is low powered but very high quality. The second amplifier is high powered, but of lesser audio high quality. (It’s a lot more difficult to achieve very low distortion in high powered amplifier stages). Peter designed a way to compare the high powered output with the original audio input and derive the required error correction signal which is then injected into the audio path, in such a way that the high power audio output achieves a very low distortion figure, even at very high power levels. This innovative product earned Quad the Queen’s Award for Technological Achievement in 1978..."
In the early-mid 00s Linn released their "Chakra" amps, which employ Quad's current dumping circuit modified/shrunk to analog ICs. I very much enjoyed the performance of my Majik Chakra power amp.
I suspect Devialet further improved Walker's invention, fully converting the current dumping stage to a digital platform (ideal for this purpose), while maintaining a Class A analog stage to correct errors in the current dumping section. The fact that the error correction circuit acts in the digital domain likely increases its accuracy, contributing much to the apparently stellar performance.
Independent confirmation is helpful in this case. I'd prefer my strain gauge phono stay in the analog domain rather than pass through ADC. Has any pro or amateur review described audible distortion in the ADC?
If true, I suppose I can adapt my thinking to it.
Comment at THIS review: "...is actually class A and class D run in parallel all the time and at all levels. Class A defines the sound character and provides voltage while the class D stage deliver current and ‘drive’. As far as I’ve understood, the class A amp also outputs a correction signal (created by the powerful DSP) to cancel the switching noise inherent to most class D..."
Peter Walker of Quad invents "Current Dumping" amp:
"...Peter put this principle into practice using two amplifiers per channel instead of one. The first stage ‘error’ amplifier is low powered but very high quality. The second amplifier is high powered, but of lesser audio high quality. (It’s a lot more difficult to achieve very low distortion in high powered amplifier stages). Peter designed a way to compare the high powered output with the original audio input and derive the required error correction signal which is then injected into the audio path, in such a way that the high power audio output achieves a very low distortion figure, even at very high power levels. This innovative product earned Quad the Queen’s Award for Technological Achievement in 1978..."
In the early-mid 00s Linn released their "Chakra" amps, which employ Quad's current dumping circuit modified/shrunk to analog ICs. I very much enjoyed the performance of my Majik Chakra power amp.
I suspect Devialet further improved Walker's invention, fully converting the current dumping stage to a digital platform (ideal for this purpose), while maintaining a Class A analog stage to correct errors in the current dumping section. The fact that the error correction circuit acts in the digital domain likely increases its accuracy, contributing much to the apparently stellar performance.
