If you're old enough to have grown up with a parental radiogram, you'll remember how it sounded. It had what the adults called 'a lovely tone,' as thick as the gravy you had for Sunday lunch and about as transparent. Indeed, turning the knob marked 'Tone' would only make it more congealed, by giving a severe treble cut. Hi-fi separates manufacturers, though, adopted the superior tone control circuit devised by Peter J Baxendall, cleverly using the amplifier's negative feedback loop to provide boost as well as cut. A treble cut in the feedback loop gave a treble boost at the output, while a bass cut produced a bass boost.
展开▼
