GoldenEar Class D
Amplifiers

The SuperSub XXL 1400 Watt Class D Amplifier
Classy Class D
In the last edition of our newsletter we discussed common audio amplifier classes. Now we'd like to tell you about the advanced amplifiers we've developed for our GoldenEar powered systems. You might suspect that since they "only drive the woofers" we've chosen to use off the shelf generic amplifiers, an easy and inexpensive choice. Well, nothing could be farther from the truth. In Sandy and the engineering team's mission to bring truly spectacular sonic performance to you at affordable prices they consistently put our resources where they count most: in elements that deliver on that stated mission. And the amplifiers we've developed for our speakers are perfect examples of that.

Early Class D amplifiers rightly had a mixed reputation among audiophiles for a number of reasons. However as time and development have progressed, advanced Class D amplifiers have gained the respect of many in the high end audio community and they can now be found in some excellent products.

The amps in the Triton powered bass sections and our subwoofers are all advanced "Class D" high efficiency types with switching power supplies meaning they don't require large, expensive power transformers. Since the GoldenEar amplifiers are dedicated to our proprietary low frequency bass drivers we can precisely match their performance to the electrical and acoustic characteristics of those drivers. And we're not just talking about equalization using the Digital Signal Processing (DSP) built into these amps that enhances the speaker's performance. Because we know the exact speaker driver(s) that each amplifier will be connected to, engineering can make sure that the amplifier/speaker interface and operation is totally optimized. Here are a few technical highlights about the GoldenEar Class D amplifiers:
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  • GoldenEar amplifiers incorporate advanced computer controlled operation. A high speed Programmable Logic Device (PLD) controls the Class D output stage in real time. It manages such things as soft clipping (reducing the possibility of the amplifier damaging the speaker by being overdriven), DC offset control, power on/off control, output stage anti-saturation protection and audio muting. All this contributes to the reliability and very low Total Harmonic Distortion produced by these amps as much of the output stage control logic takes place in the PLD.
  • Fundamental circuit distortion is an order of magnitude less (less than 0.1% THD without negative feedback) than typical Class D designs and much less negative feedback is needed to achieve low distortion, yielding excellent stability and superb transient response. The power supplies are very low impedance designs capable of delivering large amounts of current for high demand transients, especially critical for the demands of subwoofer operation.
  • Up to 56-bit DSP capability means the digital optimization of performance is at an extremely high level of precision. The high resolution processing ensures superb signal processing with low distortion and excellent fidelity to the original source. 
  • The amps all include Digital Signal Processing audio filters and limiters. The limiters have up to 26dB of range (twice that of typical analog limiters used in the past). The limiting is frequency-dependent, as the limiter selectively applies limiting based upon the driver and enclosure's ability to reproduce different frequencies. Ultimate driver excursion is controlled by the DSP for best linearity at high power levels.
  • All subwoofer audio equalization is done in the digital domain with 0.01% accuracy. (By comparison, analog filter solutions struggle to provide 7% filter accuracy). Level errors in the filters are kept to well under an inaudible 0.1%dB compared to analog filter solutions that often exhibit combined filter errors of several dB or more, leading to sound differences between any two speaker samples.
  • The micro-processor based control of the PWM (Pulse Width Modulator, see the last newsletter for more on PWM) link between the DSP and the Class D power amp stage allows the "tuning out" of THD errors in software for ultra-low system-wide THD specifications.
     
  • Lightning fast processor-based overload protection (only a 45uS update time) and processor based auto turn-on allows for precise, silent control of system power on/off.

These amplifiers are just another example of what makes GoldenEar different. The ground breaking performance GoldenEar achieves in terms of price and enclosure size isn't the result of magic. It's due to an exceptionally talented engineering team focused on Sandy's vision: Superb audio capability and great musical enjoyment from speakers that easily compete with others that sell for several times their price.
 
For specs on individual GoldenEar units please go to GoldenEar.com .
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