These requirements cover power-operated musical instruments and accessories rated 300 volts or less, intended for household and commercial use on supply circuits in accordance with the National Electrical Code, NFPA 70. Musical instruments include organs, electronic pianos, music synthesizers, and other such products that produce music under the direct control of the player. These requirements also cover accessories for use with musical instruments, such as rhythm generators and similar equipment having self-contained tone generators, tone cabinets, music tuners, and the like. These requirements do not cover commercial audio equipment, such as amplifiers, mixers, and signal processors for general use; or special effects units, amplifier-speakers, and the like, that are intended for use by professional and semiprofessional musicians. These requirements do not cover musical instruments that are categorized as electrically operated toys and are covered by the Standard for Electric Toys, UL 696. A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire, electric shock, or injury to persons shall be evaluated using the appropriate additional component and end-product requirements as determined necessary to maintain the acceptable level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific provisions of this standard cannot be judged to comply with this standard. Where considered appropriate, revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.