Of all the components in an audiophile system, the amplifiers draw the most electricity and cost the most to use. Class A amps are always running at full power, drawing 4 times their rated power to reach spec. That means a Class A solid state or vacuum tube amp rated at 100 watts per channel will draw 800 watts continuously, dissipating 600 of those watts as heat. Class A tube amps are the least efficient amps on the market and deserve careful thought before purchase, those 800 watts can cost about $75 per month on your electric bill. Do they sound better than other types of amps? Some audiophiles think so but when we compare the total harmonic distortion between a tube amp and one of the new Essence™ digital amps, the Essence distortion spec is 1000 times lower and they are much less expensive to operate.
In the 1960’s, engineers pioneered the first solid state amps for hi fi applications, known as Class AB. These amps are 50% efficient, meaning half their output power is dissipated as heat and 50% is turned into watts to drive your speakers. Instead of being on at full power all the time like the Class A types, the Class AB amps are switching their transistors on and off to increase efficiency and lower distortion. If you have a Class AB amp rated at 200 watts x 2, it takes 800 watts of utility power to meet spec. When not in use, even if they’re on, they consume no power at all, lowering the power bill per month for just the amp to between $25 and $50, depending on how much its used.
Class AB amps are materials intensive, they require a large chassis with plenty of heat sink and fan cooling, one reason for their high cost is the packaging to make them work. All that weight adds to the freight costs that increase the carbon costs too.
Now we have the next generation of amps, called Class D, which some people think stands for “digital”. Its a convenient way to think about how Class D amps work, they certainly are not analog, they use Pulse Width Modulation method to amplify analog signals, faster than any other type of amplifier now on the market. These are the first amplifiers that increase efficiency to 90%, meaning only 10% is wasted. These are the least expensive to operate ($10 per month) and you get a lot more power for your money at a much lower level of distortion. Because they are efficient, they run cool and dont need huge heat sinks or fans, their chassis can be much smaller and lighter, lowering the production cost.
They also have the lowest distortion (typically .002%) in audio history and are completely silent, two features audiophiles hold dear. As an analogy, Class AB amps are like the incandescent light bulb, Class D amps are like LED lights. Due to climate change and global warming, everybody, including audiophiles, needs to reconsider the use of in-efficient, high carbon cost power amps. Modern thinking people wont hesitate to upgrade to digital amplification; its cheaper, cleaner, and eco-friendly.
Essence™ has a digital amp in production now, shipping in September. Preliminary specs are 125 watts x 2 into 8 ohms, 250 x 2 into 4 ohms, and 500 watts bridged for mono into a 8 ohm load. THD is rated at not more than .02% from 20 Hz to 20 KHz and is down to .003% across most of the audible band. Separate gain controls are provided for each channel along with balanced XLR inputs and single-ended RCAs. Deluxe 5-way binding posts connect the amp to your speakers.
Essence™ is committed to an all digital system architecture for hi res playback. The amps join the our 24/192K HDACC Preamp and Essence Electrostatic speakers to form a digital playback system that according to Wikipedia will reproduce hi res content that’s 200-300% cleaner than conventional speakers, with superior stereo imaging, clarity, and resolution. Live your life in Hi Res with Essence™, nothing makes more sense now.
As Robert Harley concluded in his Absolute Sound report on Class D amps “certain sonic qualities — dynamics, bottom-end weight and control, transparency — seem to come much more easily to Class D than to linear designs. This is somewhat true in an absolute sense, but startlingly so when Class D amplifiers are compared to similarly priced linear models. At a given price level, Class D outperforms conventional designs in some performance parameters.