How much headroom is enough?
Subscribe to Ask Paul Ask a QuestionCan you ever have enough headroom? What benefits does headroom afford and how is it measured?
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Can you ever have enough headroom? What benefits does headroom afford and how is it measured?
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Paul has mention his thoughts on McIntosh before. He’s not a fan, but they have a ton of headroom. So that must be why he mentioned that headroom is great IF the amp is designed correctly to be musical.
Paul is saying (if I understand correctly) that the amplifier sounds best in the range where the open-loop characteristic is basically linear. Beyond this, the open-loop performance is not so good, and so overall negative feedback has to work harder, with a detrimental effect on sound quality.
Two questions occur:
(a) If a designer could create a circuit with excellent linearity across an extended portion of the output range, perhaps using local negative feedback, the amplifier might have some additional complexity, but overall there should be a saving in cost from lower capacity power supply and output devices.
(b) How does this apply to Class D? Can you measure open-loop performance in Class D, and does the 20% rule of thumb apply in a switching output stage?