Technical Description
Control Circuit is unacceptable for use in the C2300, as it does not match the classic McIntosh Volume Control Audio Taper. The C2300 incorporates electronic circuitry together with sophisticated firmware to produce electroni- cally the classic McIntosh Volume Control Audio Taper, while maintaining the channel balance and freedom from control noise.
The Volume Control on the Front Panel of the C2300 is actually a special digital optical encoder. As the Volume Control is rotated, a beam of Infra Red Light is picked up
by two internal sensors as a series of digital pulses. Refer | ||
to the exploded view in figure |
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Optical Disc | ||
29. The number of and time | ||
Infrared | ||
between pulses are counted by | ||
a Microprocessor which in turn | LED | |
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controls the McIntosh designed |
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Precision Electronic Attenua- |
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tor that provides 213 steps in | Sensors | |
0.5dB increments and maintains | ||
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the channel balance to within + | Figure 29 | |
0.1dB.
With most Preamplifiers the Volume Control is placed ahead of the Amplifying Circuitry providing large dynam- ic range and freedom from input overload however, back- ground noise level is higher at lower settings of the volume control. By placing the Volume Control after the Amplify-
ing Circuitry there is lower background noise however, a reduction in dynamic range and input overload is the result. The only correct way to design a high performance Preamplifier is with two volume controls. This provides the benefits of wide dynamic range, freedom from Input overload and a background noise level that actually goes down as the volume control setting is reduced. The special controlling circuitry for this dual volume control design is known as the McIntosh “Dynamic Control Multiplexer”.
Meter and Circuitry
McIntosh solved the problems with ordinary meters in the C2300. By developing electronic circuits the meters are made to respond to short intervals with an accuracy of 95%! To permit the eye to see such high speed motion, the electronic circuits that drive the meter pointer are time stretched. Special logarithmic circuitry allows the meter to indicate a 60dB plus range, without resorting to a Meter Range Switch.
Power Supply Circuits
To compliment the design of the C2300 there are fully regulated power supplies. The special “R” core transform- ers supplies the necessary voltage/current for the low and high voltage regulated circuitry.
C2300 Block Diagram
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