Trafomatic Rhapsody Integrated Amplifier Lab Report

Lab Report

With the 'Anode Dissipation' mode set to 'Solid' the Rhapsody succeeds in achieving its 2x20W rated output into 8ohm, albeit at 7% THD. The relationship of distortion versus power output is fairly linear in this instance, the amplifier offering 8.3W, 12.0W and 16.8W into 8ohm at 2%, 3% and 5% THD, respectively, and 7.5W, 11.0W and 16.0W into 4ohm (via the 4ohm tap) also at 2%, 3% and 5% THD, respectively. There's a little extra output available under dynamic conditions, to the tune of 20W/8ohm and 13.5W, 6.5W and 8.5W into 4, 2 and 1ohm, respectively, via the 4ohm tap [all up to 5% distortion, see Graph 1 below]. Sensitive loudspeakers, like the DeVore models from Absolute Sounds' Ten range, are ideal partners although the amplifier's modest 83.5dB A-wtd S/N (re. 0dBW) and –63dBV residual noise suggests some mild background hiss may still be audible.

The Rhapsody's 'colour' extends well beyond its gorgeous metallic red chassis, particularly at bass frequencies where THD is ~2% at 20Hz/1W before falling away to a steady ~0.35% through mid and high frequencies. At just 5W output into 8ohm, distortion hits ~9%/20Hz – presumably through transformer core saturation – and falls to a minimum of 1.3-1.5% through mid and treble [see Graph 2, below]. This is significantly higher than we typically measure from today's loudspeakers at 90dB SPL/1m, for example. Additional colour is introduced from the Rhapsody's interaction with the attached loudspeaker's impedance trend but is already reflected in a response which shifts from a 'flat' +0.4dB to –0.6dB into 8ohm down to +1.0dB to –20.3dB into 1ohm (all 20Hz-20kHz). Reviews of the Rhapsody should be judged as very specific amplifier/speaker combos. PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 2.9A


Distortion versus frequency versus power output (1W/8ohm, black and 5W/8ohm, red)

Power output (<3% THD, 8/4ohm) 12W (8ohm tap) / 11W (4ohm)
Dynamic power (<5% THD, 8/4/2/1ohm) 20W / 13.5W / 6.5W / 8.5W
Output imp. (20Hz–20kHz/100kHz) 1.9-2.3ohm / 2.6ohm
Freq. resp. (20Hz–20kHz/100kHz) +0.4dB to –0.6dB / –6.8dB
Input sensitivity (for 0dBW/20W) 125mV / 660mV
A-wtd S/N ratio (re. 0dBW/20W) 83.5dB / 96.5dB
Distortion (20Hz-20kHz, 1W/8ohm) 1.8-0.35%
Power consumption (Idle/Rated o/p) 240W / 243W
Dimensions (WHD) / Weight 470x260x370mm / 32kg
Price £19,998

Trafomatic Ltd
Supplied by: Absolute Sounds Ltd
0208 971 3909