AI-generated product photo — not official manufacturer imagery.
Estimated price (community-sourced)
Around — community and catalog average, updates slowly
The Ypsilon Aelius is a hybrid monoblock power amplifier that uses a single-ended class-A tube input stage transformer-coupled to a push-pull MOSFET output stage, implemented with only two gain stages and no overall feedback for high transparency and musicality. Its original design employed a NOS Siemens C3g pentode tube for the input stage with tube rectification (EZ81/6CA4), while later production has also supported alternative small-signal tubes depending on market and revision. The current Aelius specification is 200 W RMS into 8 ohms and 350 W RMS into 4 ohms, with approximately the first 60 W operating in pure class A before transitioning to class AB, providing substantial power and control for real-world loudspeakers while retaining single-ended-like purity. The amplifier uses an interstage transformer for phase splitting and low-impedance drive to the MOSFET output devices, preserving signal integrity and wide bandwidth. Published specifications list a bandwidth of 11 Hz-75 kHz (-3 dB), input impedance of 47 kohm, voltage gain of x30 (~29.5 dB), and output impedance around 0.25-0.4 ohm depending on revision and measurement. The Aelius chassis measures about 425 x 425 x 230 mm (W x D x H) and weighs roughly 45 kg (99 lb) per unit. It is equipped with balanced (XLR) and unbalanced (RCA) inputs, with a rear-panel switch to select input type, and includes a ground-lift switch to help minimize hum from ground loops in complex systems. Hand-built in Greece, the Aelius is widely described by reviewers and distributors as combining high power, transparency, dimensionality, and a spacious soundstage, and is positioned to drive virtually any high-quality loudspeaker while maintaining the refinement associated with Ypsilon's tube-based designs.
Amplification power output and characteristics
Analog signal output specifications
Input and output connections
Size, weight, and appearance
Specifications are community-contributed and may not be accurate or complete. Verify all details with the manufacturer before making purchasing decisions. Terms & Conditions
Components that show up alongside the Aelius in real systems. A verdict means the pair has been checked for compatibility and headroom — open it to see how the two get along.
The closest alternatives on specs, description and the systems they turn up in, with the specs they share set side by side.
The M-900u's power @ 8ω is 150W against the Aelius's 200W, its power @ 4ω 300W against 350W, its output impedance 0.012Ω against 0.25Ω, and its input impedance 51Ω against 47Ω.
The A200's power @ 8ω is 120W against the Aelius's 200W, its power @ 4ω 200W against 350W, its output impedance 0.016Ω against 0.25Ω, and its input sensitivity 0.7V RMS against 1.0V RMS.
The Atlas's power @ 4ω is 400W against the Aelius's 350W and its input impedance 470Ω against 47Ω. Both share power @ 8ω (200W) and output impedance (0.25Ω).
The Delta Mono's power @ 8ω is 300W against the Aelius's 200W, its power @ 4ω 600W against 350W, and its output impedance 0.01Ω against 0.25Ω. Both share class (A).
The specs and the pairings above are open to everyone. Sign up and you get the system builder, the assistant, a compatibility check against the gear you already own, and a watch on this product so a price or pairing change reaches you.
Sign up freeConstellation Audio Inspiration 1.0