Madrigal Imaging Five Channel Amplifier manual Special Design Features, Multiple power supplies

Multiple power supplies

Low impedance power supply

Balanced inputs

Robust output stage

Extensive protection

Special Design Features

Congratulations on your purchase of a Proceed amplifier! While your new ampli- fier is straightforward in its use, it includes several design features which are re- sponsible for its outstanding performance. A few of these are given below.

Unlike other multichannel amplifiers, your new amplifier maintains outstanding isolation and independence among its five channels. Three large toroidal trans- formers are used, with complete left/center/right channel separation maintained throughout. Separate secondary windings for front vs. rear channels on the Left and Right transformers feed separate rectifiers and separate banks of filter caps. In short, after the transformer, each channel has its own, dedicated power supply.

This approach reduces crosstalk between audio channels for superior imaging and reproduction of acoustic space. Any demands placed on one channel have virtually no effect on the performance of the other channel(s).

A critical factor in the ultimate performance of an amplifier is its “power supply impedance,” which can be loosely thought of as the freedom with which the au- dio circuitry has access to the power it needs, when it needs it. The design of your Proceed amplifier has addressed this important characteristic in a compre- hensive fashion. For example, the power supply capacitors (which act as “reser- voirs” of power for the amplifier circuitry) are mounted directly to the printed circuit board rather than using point to point wiring. The layout of the circuitry uses short, thick traces for high current paths. Internal current capability is further enhanced with high purity copper bus bars. This attention to detail yields an op- timal environment in which the amplifier may operate to its maximum potential.

Each channel of your amplifier is individually configurable to receive either bal- anced or single-ended inputs. This approach allows you to take full advantage of the greater immunity from noise, RFI, and EMI which balanced transmission of audio signals offers on any preamp-to-amplifier connection where it is supported. At the same time, any or all channels of the amplifier may be configured for single-ended inputs to maintain compatibility with the majority of preamplifiers available today. The gain structure of the amplifier adjusts automatically when you select different inputs to facilitate this “mix and match” approach.

Each channel of your Proceed amplifier uses ten 150 watt power transistors. These transistors are all individually tested and sorted, and are used in matched sets to ensure that no one transistor bears a disproportionate part of the overall load. The combination of an “overbuilt” design specification and extraordinary atten- tion to detail in manufacturing improves performance, reliability, and longevity.

Your Proceed amplifier will shut itself down if it senses either the presence of either DC (direct current) or a short circuit at the output, or any unsafe operating temperature. In any case, a power relay will cause the amplifier to be discon- nected from the AC mains. In addition, the AC input to each transformer is fused to protect against any possibility of component-level failure that could draw dan- gerous amounts of power. Finally, inrush limiting prevents premature aging of

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