The Mueta® benefits
 

Compact and efficient

A MUETA® amplifier capable of delivering several hundred watts fits in an enclosure about the size of a cigarette box, thanks to efficiency in the order of 90 to 95 percent and the absence of a bulky heatsink. The reduced supply voltage stability requirements mean the power supply can be much smaller, simpler and more cost effective. This reduces the overall size, a huge benefit in automotive applications where space and power are severely limited, and in home cinema systems where up to seven high-quality amplifiers are squeezed into a ‘standard’ width housing.

High-end audio performance

MUETA® amplifiers are totally ‘honest’. What comes out is the same as what goes in, only LOUDER! The frequency range spans the entire audio spectrum (from 20Hz to 20kHz), and is completely load independent (see figure 1). There is almost no harmonic distortion. Measured results (see figure 2) show THD at around 0.002%. A high-end class AB amplifier costing as much as $15,000 rarely gets better than 0.005%, while a good-quality amplifier achieves 0.01%. A very expensive non-MUETA® class D, however, struggles to reach 0.02%. The measured signal-to-noise ratio (S/N) is better than 130dB compared to 90dB for an ‘average’ audio amplifier (see figure 3). Considering a difference of 40dB would imply S/N performance 100 times better, this highlights just how accurate the MUETA® really is – just 5µV of noise on the output. This is over 50 times less than the theoretical S/N ratio of CD!

 Figure 1
 Frequency response
 (from 20Hz to 20kHz at 1dBV input)

 Figure 2
 THD + N vs Frequency
 (output power 50W RMS no filters are used)

 Figure 3
 Fastest (Multitone ) Noise at 4Ohm
 (200W equals 29dBV - 120 dBV = -149dB - 1uV noise)

Insensitivity to output load

Thanks to the MUETA® control method, it doesn’t matter what is connected to the output. Speaker-amplifier matching is usually a weak link in an audio chain, and even many of the highest quality speakers do not represent a consistent load across all audio frequencies. Most high-end amplifiers, particularly non-MUETA® class-D, are unable to deal with this. The sound fidelity of the MUETA® solution, on the other hand, is unaffected by varying loads.

Excellent bass clarity

A critical aspect in reproducing clear bass is the damping factor of an amplifier, and the output impedance determines this. Because a speaker is an inductive device, coil movement also creates a signal that can cause a ‘muddy’ sound if the amplifier has a low damping factor. The MUETA® amplifier has a damping factor of over 1000 at 10kHz, and in the critical bass region below 1kHz, it is greater than an astonishing 4000. A good quality class-AB amplifier achieves around 200 in this region, and a non-MUETA® class-D amplifier just 40! The output of MUETA® amplifiers is short-circuit protected without compromising output impedance.