Symposium introduced lateral ball bearing isolation with the original Rollerblock® in 1997; since then, Symposium's Rollerblock® Series 2 has been the standard of excellence for ball bearing isolation in the high end audio industry. Many rave reviews and customer comments reinforced their position as the premier ball bearing isolation device. However, it became evident that there was a need for a lower cost "introductory" ball bearing isolation device designed with the same audio expertise and commitment to quality as the original Rollerblock. Thus, Rollerblock Jr. became a reality.
Rollerblock Jr. consists of of 6 tops and bottoms and 3 center bearings, to make 3 "Double Stacked" isolator/coupler units. Each top and bottom is constructed of black anodized, aircraft alloy aluminum, and has a 1.875" diameter (4.76 cm) and 5/8" (1.58 cm) thickness. These dimensions were carefully chosen to make Rollerblock Jr. easy to use and set up, yet strong enough to withstand the rigors of use under heavier equipment such as large amplifiers and heavy loudspeakers. The special cup interior has been designed so that the top and bottom "sandwich" is stable with the ball inserted in the center, making for easy setup. The bottom and top are flat and suitable for all equipment chassis, as well as flat surfaces and carpeting.
Version 1.1 introduced
After its first production run, Rollerblock Jr. was modified to include a 1/4-20 threaded hole dead center on the opposite face from the cup. This threaded hole allows the Rollerblock Jr. body to be screw-mounted to many existing equipment foot fastener systems, and facilitates secure fastening to Symposium Precision Couplers (this allows making a very high Rollerblock Jr. for clearing extremely high equipment feet, or other applications) or with "hanger bolts" for securing into wood platforms, etc. Also, the alloy material of the blocks was upgraded to a higher grade aircraft aluminum. Cup sphericity and all other geometric relationships were maintained. Rollerblocks used under a large VPI turntable, and coupled together with Precision Couplers for added height.
Standard Rollerblock Jr. is supplied with 3 chromium steel balls, with Super-precision Grade 10 Tungsten Carbide balls available as an optional upgrade. This configuration is known as "Rollerblock Jr.+", with Tungsten bearings included.
Rollerblock Jr. is effective with virtually all components, especially digital sources (CD players and transports), preamplifiers, and amplifiers, but can also be used to isolate and couple entire shelves and platforms, turntables, power supplies (including AC "line conditioners") and loudspeakers. Rollerblock Jr.'s virtues, like the original Rollerblock Series 2, are subtractive in nature. That is, rather than attempting to compensate for an existing problem or deficiency in a system through the introduction of new resonance, Rollerblock Jr. is designed (as are all Symposium products) to remove the cause of resonance and distortion. Footer devices and accessories should not create another problem by adding a new resonance; many will thicken bass and lower midrange with artificial bass overhang, lending a false "warmth" and impression of superior bass, which eventually becomes fatiguing, damaging timber accuracy and transient response of the entire music system.
Proper installation results in increased transparency, dynamics and musicality, properties which include better harmonic separation and reduction of vibration-produced excessive sibilance. Further, one may expect to discern greater clarity between instruments in the sonic field, and better defined bass performance with more accurate timbral balance.
Theory of Operation
The purpose of a ball bearing isolation device is to laterally isolate a component from external mechanical waves (vibration) without inducing additional colorations or distortions (which can be induced through poor choice of materials, which in turn may resonate or vibrate, inducing new distortions in the component being treated). While it may seem that any sort of ball-and-race bearing will do (such as "marbles and spoons"), proper execution requires care and precision. The careful engineering of the problem is the difference between a "toy" and an essential component, and if not done correctly, will create new problems.
A Few of the Problems - and their Solutions
All bearings create noise, called chatter, as they roll upon a surface. This noise is directly transferred into the component, and can become a secondary source of distortion. If chatter is not adequately reduced, the "cure" can become worse than the "disease." Devices which use more than one ball induce more noise than devices with fewer balls, all things being equal. Accordingly, Rollerblock Jr., like all Rollerblock devices, use the fewest number of balls possible - one per device - to ensure the lowest possible chatter. Further, not only is the ratio of the ball diameter to the cup critical for the best compromise between mechanical stability and performance, but so is the absolute size of these elements. Symposium pioneered the lateral plane ball bearing device for use with active components; since 1996 we have experimented with many different combinations and found that a 1/2" ball with our standard cup sphericity offers the best solution for real-world performance. Many positive reviews and a virtual avalanche of positive responses from owners seem to confirm these findings.
For this reason, Rollerblock Jr. employs the same basic ball and cup relationship which is so successful in the state-of-the-art Series 2+ Rollerblock. Experiments with different cup sphericities and ball materials have suggested that while different resonant conditions may be created, lateral isolation performance is no better, and in most cases, worse.
Rollerblock Jr. uses two cups of similar sphericity, positioned in opposition to each other, with a single ball in between. This "double stack" design was invented and first described by Symposium in our original patent on the Rollerblock, which was filed in 1997 and predates all descriptions of similar "DIY" ("Do It Yourself") devices by several years. The use of a cup, as opposed to a flat surface race, has several advantages when operated without external force fields to damp ball motion (Symposium has since obtained a patent for magnetic bearing bias and stabilization; at present, this technology is employed in the Symposium Isis Rack. For a further technical discussion of the theory behind ball bearing isolation devices, please click here.
Materials Choices and Mechanical Drainage
The material used in the Rollerblock body is critical to non-resonant, neutral performance: Rollerblock Jr.'s robust aircraft alloy construction resists inherent resonance and also transmits energy through itself and out of the component to mechanical "ground" (in other words, the support surface), for best sonic results. Aluminum alloy is chosen for a specific reason: it is better as a coupling medium than brass, steels, or other materials because of its superior mechanical transmission speed which is bettered in nature only by two other metals, silver and copper; however, aircraft aluminum's excellent machinability, strength, hardness, general resistance to corrosion and reasonable cost make it the best choice.
Similarly, listening tests in different systems with various components confirmed that Tungsten Carbide was the best ball bearing material. While many might assume that this is due to Tungsten Carbide's extreme hardness, Tungsten Carbide's excellent mechanical transmission qualities, which are close to aluminum, make it a better "match" to aluminum alloy and thus a better choice than ceramic balls (which have slightly greater hardness but inferior transmission characteristics) for preserving mechanical transmissivity through the entire Rollerblock structure, a primary design consideration.
As with all Symposium products, Rollerblock Jr. is made in the USA. We're very proud of its unmatched quality and precision, as well as its rock-solid and simple-to-use design. If dynamic, engaging, and musically truthful performance is the keynote of your goal in an audio or home theater system, we are confident that you will find that Rollerblock Jr. will outperform devices at several times its price, and "open" up your existing system - or the system you will own years from now - to a new and greater level of enjoyment. If not, we will refund your money - it's as simple as that.