Key contact reliability and durability is enhanced in that the key switch current is less than that required by even a single chest magnet; in addition, it is non-inductive. This means no contact sparking... never any pitting or burning. Finally, because there are no action magnets to constantly consume power, a much smaller and less costly rectifier can be used. The total power consumption is essentially that required to operate the chest magnets.

With the Diode Matrix Switching System, no special power supplies are required, and a regular 12 to 18 Volt organ rectifier may be used. Voltage appearing at the chest magnet is about one volt less than the voltage at the rectifier. As in any organ, the minimum voltage required depends on the characteristics of the chest magnets. Polarity is important and normally the key switch feed must be positive, but the stop tablet feed can be specified to be either positive or negative.

Where couplers are used, a separate solid state coupler system may be mounted in the console or in the organ chamber. When certain features are required, a Peterson OrgaPlex(TM) coupler system is often used with a Diode Matrix relay. If desired, a conventional console having mechanical couplers can be connected in the usual manner. Where any Peterson Solid State Coupler System is used, each playing key operates a single key contact, which controls all functions.

The modular design of this system, together with its unique proprietary connector system, allows unlimited future additions or changes with no preparations and with no cost penalty. It is also practical to add a Diode Matrix System to control new ranks that are being added to an old organ with an electropneumatic or other existing relay.

Each Peterson Solid State Switching System includes a Sforzando terminal which, when energized, turns on all stops. Any stops not desired in the Sforzando combination may be deleted by clipping a wire or unsoldering a connection. The provision of the Sforzando terminal saves the very considerable cost of special Sforzando switches and wiring that was traditionally required.

The operation of the Diode Matrix relay is remarkably simple. A comprehensive technical manual, which describes in simple terms how the equipment works, is supplied with each system. Even without this resource the modular concept, logical layout of the various components, connectors and built-in test junctions make trouble shooting easier than with most other relays, electronic or otherwise. Consider, for example, the common "cross" or "run" where two or more notes sound together. Usually, the short circuit causing this can be in any of several locations, but with the modular concept, the various assemblies can be quickly disconnected from one another and the trouble immediately localized. Components and connector terminals are mounted on special printed wiring boards in octave groups so that the parts related to a specific function are readily

identified. While a complete system necessarily looks complex, a more careful examination shows it to consist of a large number of identical, very simple, easily understood circuits. Any technician who can find his way around a mechanical relay will quickly feel at home with Peterson Solid State.

Each type of Peterson control system has advantages for particular organ specifications. The Peterson Diode Matrix Switching System is often less expensive on small organs with all or most of their ranks straight rather than unified and where features such as a transposer, MIDI interface and/or a movable console are not required. In some cases, Peterson will recommend a "hybrid" control system using OrgaPlex(TM) couplers connected to a Diode Matrix Switching System to operate the note actions. Peterson's technical staff will be happy to discuss options and pricing with you.