Power Supply Circuits

Figure 21

of the two amplifier circuits, allowing each ampli- fier cir- cuit to be optimized using its own power supply. Refer to figure 20. High power

amplifiers draw high current from the AC power line. The very large Power Transfomer, has toroidal windings on a toroidal core and can supply over 35 amps of continuous current. Refer to figure 21 (golf ball is for size compar- sion). It is enclosed in the legendary McIntosh Potted Enclosures and weighs over 12.06kg. The super size main filter capacitors can store over 600 Joules of energy for the five amplifier channels, necessary for the wide dynamic range that “Digital Audio” demands. The power amplifier draws high current from the AC power line. Therefore, it is important that they plug directly into the wall outlet. Also, most owners desire one power switch for the whole audio system. The MC1.2KW is equipped with a circuit that provides remote Power Control from a McIntosh A/V Control Center. When the A/V Control Center is switched On, a (+5V) signal operates the power relay in the MC1.2KW. The MC1.2KW also has a remote Power Control Out Jack. The Power Control signal from this jack is delayed by a fraction of a second so that the turn on power surge of the next power amplifier occurs at a later time. This helps prevent power circuit overload that could trip circuit breakers or blow fuses, a very important feature in a high power Home Theater System employing three or more MC1.2KW Power Amplifiers.

Figure 18 With Power Guard

Figure 19

Without Power Guard

Technical Description, con’t

audible and inaudible distor- tion levels exceeding 40%. The audible distortion is unpleasant to hear, but the inaudible ultrasonic distortion is also undesirable, since it can damage valuable loudspeaker system tweeters. You will never experience the harsh and damaging distortion due to clipping.

The Power Guard circuit is a waveform comparator, moni- toring both the input and out- put waveforms. Under normal operating conditions, there are no differences between the shape of these waveforms. If an amplifier channel is overdriven, there will be a difference between the two signal waveforms. When the difference exceeds 0.3%,

the Power Guard activates the PG light and a dynamic electronic attenuator at the amplifier input reduces the

input volume just enough to prevent any further increase in distortion. The Power Guard circuit acts so fast that there are absolutely no audible side effects and the sonic purity of the music reproduction is perfectly preserved. The MC1.2KW Power Amplifier with Power Guard is not limited to just the rated power output, but will actually produce distortion free output well above its rated power due to the McIntosh philosophy of conservative design.

To compliment the fully balanced design of the MC1.2KW there are two high voltage power supplies; one for each

CIRCUIT

BREAKER

Block Diagram

of the

Power Supply

Figure 20

MC1.2KW specifications

The McIntosh MC1.2KW is a powerful monoblock amplifier designed for audiophiles who demand top-tier performance and precision. With a robust power output of 1,200 watts into an 8-ohm load and a staggering 2,400 watts into a 4-ohm load, this amplifier is engineered to drive even the most demanding loudspeakers with ease. The MC1.2KW exhibits impressive dynamic range, making it an ideal choice for reproducing both subtle nuances and explosive crescendos in music.

One of the standout features of the MC1.2KW is its use of McIntosh's advanced Autoformer technology. This transformer allows the amplifier to deliver full power regardless of the speaker impedance, which ensures that users can connect it to a wide range of speaker systems without sacrificing performance. This provides versatility and reliability, as it can effortlessly transition between different speaker loads.

Another key characteristic of the MC1.2KW is its unique Power Guard system. This technology continually monitors the audio signal and adjusts the output to protect both the amplifier and connected speakers from distortion and clipping. This protection processes help ensure that listeners enjoy an uncompromised audio experience, while also prolonging the lifespan of the equipment.

The MC1.2KW features a sleek and elegant design, complete with McIntosh's iconic glass front panel and illuminated logo. The distinctive blue watt meters not only add a touch of aesthetic appeal but also offer a visual representation of the amplifier's output, allowing users to monitor performance at a glance.

Additionally, the unit is equipped with a balanced input and a high-quality 12V trigger, allowing for seamless integration into any high-end audio system. The robust build quality, coupled with meticulous craftsmanship, ensures that the MC1.2KW can withstand the rigors of everyday use while delivering impeccable sound quality.

In conclusion, the McIntosh MC1.2KW monoblock amplifier merges cutting-edge technology with stunning design to provide audiophiles with an unparalleled listening experience. Its powerful output, versatility, and innovative features set it apart in the competitive world of high-fidelity audio. Whether for music enthusiasts or serious home theater setups, the MC1.2KW stands as a testament to McIntosh's dedication to superior sound reproduction.