The Philips EL 3522 is a vacuum tube amplifier that was produced in the 1970s. It features a unique design with a classic aesthetic, often appreciated by audio enthusiasts for its warm sound characteristic attributed to the vacuum tube technology. The amplifier typically operates with a tube configuration that may include 12AX7 and EL34 types, providing around 15-20 watts of output power. This output is generally suited for driving medium to high-efficiency speakers, allowing it to perform well in home audio setups. The EL 3522 is equipped with multiple input options for various audio sources and may include tone control features to enhance sound customization. The build quality is solid, with a metal chassis that supports durability and longevity. Many users admire its sound signature, which delivers a rich and full-bodied audio experience, making it ideal for various genres of music. Some models may also have unique features like a headphone output or speaker protection circuitry.