Technical Description, con’t, Power Output Meter

Figure 14

Figure 15

Technical Description, con’t

feedback designs.

The fully Balanced Push-Pull design is used from input to output. The resulting fully balanced configuration can- cels many forms of audible distortion and greatly improves the Signal-to-Noise ratio of the amplifier.

While conventional designs only take output from the plate, the Patented Unity Coupled Power Amplifier Circuitry takes the Power Output from both the plate and cathode of the Power Output Tubes. This allows for only one half of the turns ratio in the Output Transformer used in conventional designs. The result is much lower distor- tion, wider bandwidth and increased loudspeaker damping factor. Refer to figure 13.

Figure 13

The output signals of the two matched Patented Unity Coupled Circuit Power Amplifiers operate in a push-pull balanced circuit and are coupled together in the unique McIntosh MC2301 Dual Core Output Transformer. Refer to figure 14. It provides low distortion power transfer at frequencies from below 20Hz to well beyond 20,000Hz with optimum impedance points of two ohms, four ohms and eight ohms. The unequaled expertise of McIntosh in the design

and manu- facturing of trans- formers is legendary in the high fidelity industry.

Preci- sion metal film resis- tors and low dielec- tric absorp- tion film capacitors

are used in all critical circuit locations. The circuit design of the MC2301 contributes to low operating temperatures using convection cooling. No fans are needed.

Power Output Meter

The McIntosh MC2301 has a large Output Watt Meter that responds 95% full scale to a single cycle tone burst at 2kHz. Refer to figure 15. The voltage outputs are electroni- cally measured and fed to a special circuit that accelerates the pointer

movement in the upward direction. When the pointer reaches

its peak it pauses only long enough for the hu- man eye to perceive its position, then drops.

It is almost 10 times faster than a professional VU meter. A front panel switch is provided to change the meter to

the Watts Hold Mode of operation. This allows fast upward movement of the pointer but greatly increases Hold Time at the peak of its travel. The highest power output of the source material is thus recorded.

Sentry Monitor Protection Circuit

The MC2301 incorporates the newly designed Sentry Monitor Tube Protection Circuitry. Refer to figure 16. This circuit provides protection to the Power Amplifier in the event of an improper load (mismatched impedance), shorted loudspeaker cable or if a Power Output Tube

Figure 16