Slip Rings for Leslie Organ Speaker

Mercotac® Brushless Slip Rings have long been the preferred choice across many industries and applications since their inception with the Leslie Organ Speaker.

Key advantages include elimination of wire breakage, 360-degree continuous rotation, zero maintenance required, very low electrical resistance, and the ability to handle power and data signals, all in a compact design.

The Leslie Organ Speaker sparked the invention of the brushless slip ring in the 1960s when brothers Don and Bob Leslie worked together to improve the speaker’s sound quality. This new brushless slip ring inside the speaker cabinet allowed for a continuous transmission of electrical signals between the stationary amplifier and the rotating drum speaker to create the unique tremolo sound associated with the Leslie speaker. After many failures using a regular brush type slip ring this new brushless slip ring assembly eliminated the traditional shortcomings associated with the rubbing brushes and the resulting wear causing crackling sounds and having a short life. Instead, with this new brushless slip ring the speaker delivered pristine, high-fidelity sound, which quickly gained popularity at home and among numerous bands.

Leslie Organ Speakers, dating back to the 1940’s, were originally built using stationary speakers with the Leslie tremolo created by rotating baffles or horns. In the 1960’s, as an improvement to the Leslie sound, the Rotosonic drums were invented. This drum rotated the speaker instead of using baffles. In order to rotate the speaker there needed to be a high quality rotating electrical connection which made the invention possible. The results were that the tremolo effect of the speaker was greatly improved. As the Rotosonic speaker spins, the sound is altered by both the Doppler effect and also, depending upon which direction the speaker is facing, the change in sound amplitude. The Doppler effect causes the sound to slightly change pitch upwards as the speaker is heading towards the listener and then it goes slightly down as it heads away. This complex interaction between amplitude and pitch change results in the Leslie tremolo. These effects refine the sound of organ speakers to provide a deep theatre tremulant sound. The most common Mercotac Brushless Slip ring used in these products is the Mercotac Model 205, which is equivalent to the Original Leslie part # 015941 known as the Mercotac model 590.

Depending on the specific model and production year, these Leslie Model Numbers may include the roto-sonic drum and/or a Mercotac™ slip ring: 103, 205, 415, 590, 600, 610, 700, 710, 715, 720, 722, 750, 815, 822, HL-422, HL-722, HL-822, and X-77.

Utilizing this new brushless slip ring technology, Mercotac Inc. was founded in 1978 to manufacture these unique, high quality, low cost brushless rotating electrical slip rings. It was then discovered that many other applications could use the benefits these slip rings provide. Over the years the design and manufacturing process has gone through continual improvement and the product line greatly expanded from the original single model. Mercotac brushless slip rings have since the beginning been developed to meet the needs of a variety of industrial machinery and other applications