The NuForce Capacitor Array Technology

Beginning with its implementation in the Reference 18 Mono Power Amplifier, NuForce Cross Matrix Array (CMA) capacitor board has been designed to improve power delivery to its new, large-chassis amps. In order to describe what sets the CMA apart, a bit of background is in order.

Typically, for an amplifier to deliver large amounts of electrical current on demand, an equal amount of current is held in reserve within its power supply¸ filter-capacitor stage. Received wisdom would have us believe that, in order to be as effective as possible; these current-delivery systems need to reside in larger or, alternatively, a greater number of capacitors. In practice, however, the matter is considerably more complex.

Along with other amplifier components, a capacitor possesses features that are often hidden from obvious view. In engineering terms, we refer to these concealed aspects as parasitic parameters. In the case of capacitors, inductance and resistance comprise the principal parasites. In practice, they combine with capacitance to produce an unwelcome resonance at certain frequency bands. Among other potential negative effects, if left unattended, this resonance can reduce the speed of power delivery significantly below what theory would otherwise suggest. Simply using larger sizes or quantities of a single value, as is commonly done, leads to a single resonant frequency of a large magnitude. From a design standpoint, this is a worst-case arrangement.

Having identified these issues in our development of the Ref 9 Series, we addressed them with the Sequential Linear Array (SLA) capacitor board. Operating within the Ref 9 chassis-size limitation, the SLA dealt well enough with the problems we mention here. The SLA represents a reasonable, cost-effective compromise. In transcending î™”easonable,?we recognized that further improvements would require more space.

And so we developed the CMA as a no-compromise route to the ultimate in performance. The Ref 18 CMA employs the highest-quality capacitors of various values arrayed in a quasi-random pattern in order to spread resonances over a wide range of low-amplitude frequencies. In order to minimize stray magnetic fields, and hence, to reduce parasitic inductance, the capacitors are positioned so that their polarities are reversed with respect to each other. By lowering inductance, any remaining resonance is elevated to frequencies where its elimination becomes an easier task. Finally, low-value resistors combine with capacitors in strategic locations in order to dampen residual resonances. In engineering terms, the resonant peak Q, in other words, its steepness, is reduced to a value of 0.707 or lower, thus enabling damping to operate to a degree where resonance no longer poses a problem.

This is no mere marketing gambit. In terms of audibility, the CMA's stable, high-speed current delivery to the amplifier stage translates to improvements the end-user will cherish.