Contains Hybrid Drive™ technology, which uses the best features of tubes and semiconductor technology to achieve the best possible sound reproduction.
- Designed with bi-amplified speakers in mind.
- 150 watt tube amplifier and 300 watt semiconductor amplifier in the same chassis.
- The tube section gives power to the middle and treble elements.
- The transistor terminal controls power-hungry bass elements.
- DualView™ power meter.
The MC451 double mono hybrid power amplifier offers a great solution for double speaker amplification. Like the MC901, the MC451 uses McIntosh's Hybrid Drive™ technology, which combines separate tube and solid-state amplifiers in the same chassis to achieve the best possible sound reproduction from a bi-wired speaker. Unlike the sensible MC901, the MC451 has a more conventional McIntosh shape and size (so it's not small either!), which makes it easier to fit into a home audio system. By adding a pair of MC451 speakers to your stereo system, you can make your beloved speakers perform better than ever before.
The MC451 consists of a 150 watt tube amplifier and a 300 watt solid state amplifier, which is more than enough power to fully control almost any speaker.
The 150-watt tube amplifier includes four KT88 power tubes located under a removable wire cage, as well as two 12AT7 and one 12AX7A signal tubes; it uses a proprietary Unity Coupled Circuit output transformer to deliver a full 150 watts to almost any speaker, whether its impedance is 2, 4 or 8 ohms. Similarly, a 300-watt solid-state amplifier delivers its full 300-watt power to a speaker with an impedance of 2, 4, or 8 ohms using Autoformer™ technology.
Designed to work in full synergy, the MC451's two amplifiers are specifically engineered to ensure that each amplifies only its intended frequencies. The large but quiet transformer produces enough power, and neither amplifier steals power or performance from the other. All this leads to easy bi-amping, thanks to which the performance and sound reproduction of the speakers rise to a new level. MC451 internal crossover Tailor each amplifier section to the connected speaker. Just set the adjustment control on the back of the MC451 to the crossover frequency point of the speaker, so that frequencies below the crossover are sent to the solid-state amplifier and frequencies above to the tube amplifier.
This adjustable crossover allows you to optimize the performance of both amplifier sections according to your speaker specifications and listening preferences. The gain level of the tube amplifier can be adjusted between -6dB and +3dB. A direct feed can also be connected to both amplifier sections, in which case the internal divider filter is bypassed.
The MC451 features an impressive DualView™ power meter. The DualView gauge features two traditional, fast-response mechanical gauges stacked on top of each other in the same gauge window; one meter is for a 150 watt tube amp and the other for a 300 watt solid state amp. Both meters work independently of each other and show a real-time power reading from each amplifier section.
Naturally, the MC451 is packed with many clever McIntosh features:
- Power Guard®, which monitors and adjusts the input signal of the 300W transistor amplifier at the speed of light, making real-time adjustments to prevent harsh-sounding and potentially speaker-damaging distortion.
- Power Guard Screen Grid Sensor® (SGS) - The 150 watt tube amplifier section features Power Guard SGS® technology. Power Guard SGS helps prevent premature pipe failure by monitoring the operation of KT88 terminal pipes. If the current gets too high, the Power Guard SGS activates a circuit that dynamically attenuates the input signal in real time to keep the tubes at a safe operating level.
- Sentry Monitor™ - a fuseless short-circuit protection circuit that shuts down the output stage before the current exceeds a safe operating level and automatically recovers when operating conditions return to normal.
- Power Control sends power-on signals to other connected McIntosh components (such as CD players, turntables, tuners, and media players) to easily turn the system on and off.
- Patented Solid Cinch™ speaker connectors that easily but securely attach speaker cables to prevent them from coming loose and potentially causing short circuits; the connectors are also gold-plated to prevent corrosion and transmit a high-quality signal through the speaker cables.
- The MC451's uncompromising look and finish are accentuated by familiar McIntosh design features. The front features a signature black glass faceplate with three clear windows that reveal the vacuum tubes, a DualView gauge, two rotary control knobs, an illuminated logo, and aluminum handles. The top is highlighted by block diagrams printed on glass inserts, outlining the device's circuits and specifications. All of this is housed in a stainless steel body that has been polished to a flawless mirror finish.
Technical information:
- Amplifier power: 150 + 300W @ 2, 4 or 8 Ohms
- Frequency response: 10 Hz to 70 kHz (+0, -3dB)
- Signal-to-noise ratio: 112 / 118 dB
- Dynamic reserve: 1.2/2.5 dB
- Dimensions (W x H x D): 45.4 x 30 x 54.6 cm
- Weight: 60.3 kg
