A modern MONA integrated amplifier, equipped with a Canadian Hammond power transformer model 290DX. The amplifier uses KT88 tubes, which are known for their robust power output and high quality sound. They are popular in high end audio applications, such as hi fi audio systems. The amplifiers use of KT88 tubes can result in a warm and clear audio output. The Hammond power transformer plays a crucial role in converting the incoming electrical power into a form thats suitable for amplification. Hammond is a reputable manufacturer of transformers known for its high quality products. Contemporary Amplifiers And Audio Technologies For Collectors.