Power FAQ
Q: NuForce's amplifier is so small and light, does it provide adequate performance?

A: NuForce's amplifier utilizes high-performance switch-mode power supplies (SMPS). SMPS, as opposed to traditional huge and bulky linear power supplies, offers smaller size and higher efficiency. Most importantly, SMPS operates at much higher frequencies. These are thousands of times faster than linear power supplies operating at 50/60Hz. Therefore, they respond faster to provide instantaneous power as required by high-performance music reproduction. Transformers and capacitors are more efficient and smaller at higher frequency. Hence, even a very small SMPS is still several times more capable than a 50/60Hz linear power supply. SMPS also offers sophisticated over-current and short circuit protection, in addition to meeting all leading safety and industry reliability standard. Running very cool, the SMPS used in NuForce's amplifier provides an unequalled regulated output without the 100/120 Hz ripple voltage found in linear power supplies (even when huge cans of filter capacitors are used such as the case of high end amplifiers).

Q: What are Peak and RMS (Root Mean Square) power ratings? What's the effect on audio output?

A: RMS power is continuous power that the amplifier is capable of outputting over long periods. Peak power is short-term power that an amplifier is capable of briefly outputting when faced with sudden, high-energy signals. Another power measurement that is very important for audio output is the Average Power Per Cycle of sine wave.

  • Vpeak = Peak output voltage of amplifier
  • R = Speaker load in Ohm
  • Peak Power = (Vpeak)2 / R
  • RMS Power = Power supply's RMS power
  • Max Power Per Cycle = (Vpeak)2 / 2R

Headroom is referred to an amplifier's ability to go beyond its rated average power (RMS or continuous power) for a short time in order to recreate loud or explosive audio signals that rise very quickly. In order to have high headroom (an ability to achieve loud peak levels without distorting), an amplifier must have a stiff power supply with a good amount of reserve energy on which it can call (stored in capacitors). The ability of the power supply to quickly recharge the capacitors is also very critical. A typical low frequency (50Hz for example) explosive sound consists of an attack followed by a series of rapidly decaying lobes of a 50Hz sine wave. Therefore, an amplifier with 140W peak power with 20ms holdtime is capable of providing 140W power to the 50Hz musical note (full cycle of 50 Hz is 20ms). A series of successive explosive sound might sounded very close to human ear, but their base notes are far apart enough (1 second = 1000 ms) for the amplifier to provide the required peak power. For most typical home listening, hardly more than 20W of power is consumed. Therefore, a good amplifier should provide sufficient RMS power and a high peak power with low distortion (NuForce's Amplifier is capable of generating the peak power at ultra low distortion of less than 0.05% THD+N).

Q:Is NuForce's 300W amplifier less or more powerful than a linear solid state or tube amplifier rated for 300W?

A:In terms of reproducing the dynamics and headrooms of music, the more power the better. The commonly accepted measurement is to rate the output power when the amplifier clips with a 1% THD. Now, what is clipping? Clipping occurs in a linear amplifier when its output signal tries to exceed the limits of its power supply voltage. In a linear amplifier using transistors and bulky a transformer/rectifier, the storage capacitor is recharged only once every 8.33 milliseconds, and its voltage is only slightly above the maximum output voltage, so it could clip rather easily. To put it simply, it has very little headroom. With tube amplifiers, the supply voltage is very high, typically 300 to 600V. Therefore even though tube amplifiers have higher overall distortion, perceptively, they sound more 'powerful'. NuForce's amplifier is a switching amplifier designed with lots of headroom, so that there is no clipping at its rated 300W. Its 300W is perceptively better sounding than a 300W linear amplifier.