Stello HP100

About the Stello HP100

The April Music Stello HP100 is a combined preamplifier and headphone amplifier designed for audiophiles seeking high fidelity sound. It features a full discrete Class A push-pull analog stage with JFET input stage and bipolar output transistors for the headphone section, ensuring low noise and excellent dynamics. The unit includes two analog inputs (RCA), one analog output (RCA), and a Neutrik 6.3mm headphone jack. It uses a specially designed toroidal transformer and a two-stage voltage regulator power supply for stable and clean power delivery. The volume control is an ALPS Blue Velvet potentiometer, and the input impedance is a high 1 megaohm, making it compatible with a wide range of sources and headphones. The HP100 can also function as a line-stage preamplifier with gain selectable between low and high settings. It has a filter switch to roll off frequencies above 20kHz if desired. The chassis is robust, made from all-black metalwork, and measures approximately 8 3/8" W x 2 1/4" H x 11 1/2" D, weighing about 8 pounds. The sound quality is praised for its clarity, dynamics, and instrumental timbres, competing with headphone amplifiers costing significantly more. The product is no longer in production but remains highly regarded in the audiophile community.