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?
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?