Automotive Electronics

Audiophile’s Dream: First Power Supply Ever To Use Today’s Best Capacitors Receives U.S. Patent

GreenForce™, the first music signal power supply in the world that can be built using only Teflon film capacitors, has been patented by Bob Backert of RHB Sound Dezign, an electronics modification firm serving audiophiles around the world. Mr. Backert’s power supply is used primarily in RHB’s preamplifier modifications, also referred to as preamp mods. It is the first major advance in linear power supply design since the 1930s.

Bob Backert has been modifying and improving amplifiers for decades. His tubed amplifier designs are all hand-built, and never use negative feedback. “For me, it’s all about live music,” said Mr. Backert. “When you walk into a restaurant or club, you can tell right away if the music is recorded, or live. I wanted a power supply that would deliver the same speed, accuracy and powerful dynamics as live music, so it would be much harder to tell if the music were recorded. GreenForce is the realization of that dream.”

Your home’s wall outlet provides AC power, but your preamplifier requires DC to operate, which is generated by its power supply. Specifically, your preamplifier receives DC power from a part in the power supply called a capacitor. A capacitor looks, and functions, like a battery. A poor-quality capacitor will not deliver power to your preamplifier exactly as required by your music. For example, loud drum hits and bass pulses require more power than soft violins and flutes. All music requires very specific, exact power delivery to sound live. Inaccurate power impairs the tone and dynamics, and smears the timing, the “feel,” of your music.

The best category of capacitors is “film and foil”. Some of the best film and foil capacitors use polypropylene film. Many believe that the very best capacitors are those made with Teflon film.

So, the best preamplifiers have the best capacitors in their power supplies. Right? Wrong. Surprisingly, not a single preamplifier in the world has all Teflon-film capacitors in its music signal-producing power supply. Until now, with GreenForce.

Even more surprisingly, many preamplifiers, even the most expensive, use a fairly low-quality type of capacitor. These, called “electrolytic” capacitors, do not respond accurately and exactly to the power demands of your music. They age over time, further impairing sound quality. And they sometimes burst open, leaking destructive chemicals onto your preamplifier’s circuitry. Film and foil capacitors have none of these problems.

Like a flashlight using “D” batteries that won’t work with “AAA”, the power supplies in today’s preamplifiers simply require more power than a Teflon film capacitor can deliver. For example, a linear power supply that produces music signal might require capacitors with 50 uF (a tubed preamp) or 5,000 uF (a solid-state preamp). But Teflon film capacitors are much smaller. The largest size made by the popular V-Cap brand ( is 3.3 uF. Just one of these retails for $699.99. Clearly, it is not practical to use Teflon film capacitors to meet a 50 uF or 5,000 uF power supply requirement.

The patented GreenForce power supply requires only about 0.5 uF in a tubed preamplifier. This makes either Teflon or polypropylene film capacitors easily affordable. In a solid-state preamplifer, GreenForce requires only about 10 uF, which allows the use of high-quality polypropylene capacitors, a significant upgrade over the stock electrolytics.

The GreenForce power supply gives your preamplifier improved dynamics, and noticeably better, more swinging rhythm. Bass has faster attack, soundstage expands, and music becomes more tonally accurate. Orchestras and bands sound more cohesive, while solo instruments and vocals become more immediate, compelling, and “right there.”

RHB Sound Dezign can install the GreenForce power supply for less than $1,000 in most preamplifiers, phono preamps, some sources such as CD players, and some power amplifiers.

RHB Sound Dezign
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