A compact audio powerhouse ideal for guitar or PA work or for use as a general-purpose subwoofer or hifi amplifier. Many people prefer Mosfets because of their legendary ruggedness. Altronics had a Mosfet amplifier module which produced 200W into a 4 Ohm load and so we decided to take a look it. It turned out to be based on the "Pro Series One" as mentioned above, although this version by Altronics has been derated and adapted to different Mosfets. It has a rated power output of 140W into 8W and 200W into 4 Ohm. Frequency response is within 1dB from 20Hz to 80kHz. Total harmonic distortion is rated at less than 0.1% up to full power and signal-to-noise ratio with respect to 200W is better than 100dB unweighted.