McIntosh C36 Owner's Manual page 17

control circuit design. An integrated circuit operational amplifier is used with two separate
feedback circuits. One feedback loop has flat frequency response, and the other loop has
loudness compensation. A potentiometer placed between these two feedback loops makes
it possible to select any degree of frequency response from flat, to full loudness compensa-
tion. The overall gain of the loudness circuit is 20dB, which remains constant at mid frequen-
cies, regardless of the position of the loudness control. The bass and treble compensation
increase from the reference gain, and the desired amount of loudness compensation can
be selected at any volume control setting.
TONE CONTROL AMPLIFIER
The tone control amplifier uses high technology integrated circuit operational amplifiers.
The output stages have been optimized for optimum transient performance and minimum
distortion. Another set of operational amplifiers are arranged in a circuit configuration
equivalent to series tuned circuits. The series tuned circuits can be inserted into either the
input, or the feedback loop by means of a potentiometer. The proper choice of circuit com-
ponents results in a 12dB boost or cut at the desired bass and treble frequencies. When the
tone control potentiometers are at their center or detent positions, all tone control elements
are removed from the signal path, and the frequency response is perfectly flat.
TECHNICAL
DESCRIPTION
15