ESL Electrostatic

About the ESL Electrostatic

The Innersound ESL Electrostatic Stereo Power Amplifier is a specialized solid-state amplifier engineered by Roger Sanders for driving demanding electrostatic speakers. It employs a massive output stage with 18 bipolar transistors per channel, each rated at 250W, enabling peak current delivery up to 135A and preventing current clipping at high frequencies common in ESLs. Operating at high voltage (±92V rail), it provides effortless, clear sound with low distortion and exceptional stability into reactive loads below 1 ohm. Originally priced at $2995 with a 5-year warranty, it features both balanced XLR and unbalanced RCA inputs, runs cool and silently without fans or protection circuits, and excels with planar magnetic speakers as well. Production has ceased, with designs continued by Sanders Sound Systems.