PA-MC5500 THX Ultra 2-Certified 9-Channel Amplifier—Newly Released
With an advanced specification that puts it firmly in high-end territory, Onkyo’s 26 kg flagship power amplifier is sure to impress any cinephile. Benefitting from a host of exclusive amplifier technologies developed in-house by Onkyo, the PA-MC5500 power amplifier was designed as the ideal complement to the PR-SC5507 network controller.
One drawback of integrated amplifiers is that they must accommodate both digital and analog signals within close proximity of one another, raising the possibility of noise interference. To reduce such interference, audio engineers prefer to divide the pre- and power amplification sections into separate enclosures.
In the case of the PA-MC5500, Onkyo has opted for an all-analog amplification design in preference to using digital power amplification. This way, it is possible to achieve a full-bodied and musical sound quality—something that is still a rarity in the home theater world. The PA-MC5500 features balanced connections via gold-plated XLRs and non-balanced connections via solid brass RCAs. For optimal performance, the former are strongly recommended. The PR-SC5507 has balanced outputs for all channels, allowing the use of long interconnects.
Each of the PA-MC5500’s nine channels delivers a powerful 280 W into 6 ohms, more than enough to drive an ambitious home theater loudspeaker system to realistically high levels. At full output, the amplifier draws more than a kilowatt of power from the mains supply. As the THX engineers will attest, the PA-MC5500 performs with distinction in large rooms where viewers are seated more than 4 meters away from the viewing screen.
This amplifier is built on a weighty steel-plate chassis designed to be as physically inert as possible. A huge toroidal power transformer is separated from the sensitive amplifier stages by a massive heat sink that runs the full width of the amp. Working in tandem with large-capacity 22,000 µF audio-tuned capacitors, the transformer ensures a consistent supply of power under all conditions.
The PA-MC5500 employs a push-pull amplifier design with three-stage inverted Darlington circuitry to minimise distortion. It also incorporates WRAT (Wide Range Amplifier Technology), a basket of technologies developed by Onkyo to help deliver high-fidelity home theater sound.
A low negative feedback design, for instance, enables a frequency response out to 100 kHz—more than adequate for SACD playback. Meanwhile, HICC (High Instantaneous Current Capability) allows the PA-MC5500 to stay fully in control when there are speaker impedance fluctuations.
Carefully designed closed ground-loop circuits and low-impedance copper bus plates ensure that circuit noise (created by varying ground potentials) is kept to a minimum and that users hear only what the content creator intended.
To further guarantee consistent performance, especially when dealing with two-channel music, the PA-MC5500’s power amplifier channels are designed as wholly separate modules that are identical electrically, structurally, physically, and electromagnetically.
Short signal paths, symmetrically laid out power devices, and a fully discrete output stage all play their part in helping the PA-MC5500 deliver ultra-clean, high-fidelity power to a home theater’s multi-channel loudspeaker array.
