Integrated Amplifiers

Drawing a full 280W from the wall at idle, the TT Anniversary’s two black, extruded alloy heatsink ‘towers’ have hotspots that reach 70°C within one hour after switch on. During this very literal ‘warm-up’ period, distortion falls from a high 0.8% to a similarly high 0.75% (re. 1kHz/10W), a figure that’s indicative of Pathos’ ‘feedback-free’ InPoL circuit configuration [HFN Dec ’25]. Pathos suggests a distortion slightly lower than this but it’s worth noting that THD halves into 4ohm loads [red trace] from 0.075%/1W to 0.25%/10W and 0.9% at 20W (all re. 1kHz/4ohm). We saw the same with the Burson Voyager power amp [HFN Jul ’26]. That said, the TT’s limited 2x37W/8ohm and 2x22W/4ohm output [and 11W/5W into 2/1ohm, respectively, see Graph 1] suggests sensitive ‘8ohm’ speakers will still be the better match for the maximum 2.4A available current.

The tonal ‘colour’, meanwhile, is set by the dominant 2nd/3rd harmonics of the ECC803S (12AX7) triode tube input/voltage stage – more feedback applied here would reduce levels of distortion while also likely influencing the +34.9dB overall gain and 87dB A-wtd S/N ratio (re. 0dBW). In addition to the triodes themselves, the InPoL circuit’s inductor brings a ‘tube amp-like’ quality with increasing distortion at bass frequencies [Graph 2] although the ‘flat’ 0.31-0.36ohm output impedance (re. 20Hz-20kHz) is still lower than achieved by many valve amplifiers. As a result, the TT Anniversary’s unified amp/speaker response shows less variation. Into 8ohm, the bass has a –0.2dB to –0.7dB dip from 100Hz down to 20Hz while the top-end rolls gently away to –0.6dB/20kHz and –4.8dB/100kHz. However you look at the data, the TT Anniversary shouts ‘warmth and sweetness’. PM