Technically speaking, the Obelisk defies conventional measurement. Mere specifications can be wildly misleading here. Consider output power: the Si is conservatively rated at 35 watts per channel into 8 ohms. While this represents a humble enough watt/cost ratio, here 35 watts don;t exactly equal 35 watts, since the Obelisk's non-DC-coupled design behaves rather more akin to valve amplifiers (roughly speaking, Richard Hay's approach was sort of a "valve amp built with transistors") of similar rating. With this kind of power on board, better valve amps are capable of astonishing dynamic authority, and we're more than satisfied that the Obelisk Si adheres to this paradigm and then some. In practice even speakers as low as 85dB can be driven to very loud levels. Sound quality is something of a revelation at the price. We dare anyone to find any comparably priced amplifier with a more natural midrange - tubed or solid state!