AV-525
amplifier
$460
Used market: $330*
Specifications
3 of 6 values have a recorded sourceExpert Audio Engineering Commentary
Headroom Notes
A hybrid: EL84 and 6K4 tubes in the preamplifier with a WY2P rectifier, Toshiba 2SA1943/2SC5200 bipolars in the output, dual toroidal transformers. Rated 100 W + 100 W at 4 ohms and 70 W + 70 W at 8 ohms - the ratio between the two is 1.43, not the 2.0 that a stiff supply would give, which is the honest signature of a real transformer-based power stage rather than a class-D board.
What the datasheet actually says
Quoted verbatim from the manufacturer’s own page, with the date we checked it. We state what is printed, not what anyone intended by it.
«Output impedance: 4-16Ω»
Output impedance is a property of the amplifier itself, and in a solid-state output stage it is a fraction of an ohm - a value of 4 to 16 ohms would mean a damping factor below 2. What this row actually gives is the range of loudspeaker impedances the amplifier accepts; the elsewhere-stated speaker output '(4/6/8Ω)' confirms the reading. It is recorded here as the minimum supported load, not as source impedance.
checked 8/5/2026* Estimated with the depreciation fallback (~72% retained value). · checked on 8/5/2026