Pre/Power Amplifiers

Quite the most startling headphone preamp we have ever encountered is not the most powerful but it still has an (undocumented) trick up its sleeve! Currently, all the Marquis are being shipped with a moderate 10ohm source impedance (6-8ohm in practice) to better drive specialised, low impedance headphones, although the yellow/gold-anodised samples retain a higher 210ohm source impedance. Even with a ~7ohm source impedance, the Marquis' will incur a signal loss of some 1.5dB into a typical 25ohm headphone load with a commensurate undulation in system response if the headphone load varies with frequency. Moreover, into a high impedance load the Marquis' response is flat to within ±0.2dB from 20Hz-100kHz but there's a progressive bass roll-off into lower impedances. Into 25ohm the roll-off is already –1.5dB/100Hz and reaches –12dB/20Hz – an extreme result but perhaps very sensible if the equally extreme bass boost of so many modern headphones is to be countered...

Metaxas rates its Marquis 'Memento Mori' at 15V/50ohm with a gain of 26dB and distortion <0.05% (20Hz-20kHz) while, in practice, the figures are closer to 4.7V/47kohm [or 23mW/25ohm with the 200ohm version, black trace, and 135mW/25ohm, red trace, with the 10ohm version in Graph 1]. Gain is higher at 34.6dB gain and distortion is 0.013-0.05% at 1V output into a high impedance load [black trace, Graph 2]. However, into an 'average' headphone load (25ohm), distortion increases forty-fold to 0.4-2% across the same 20Hz-20kHz [red trace, Graph 2]. Distortion does remain reasonably steady with power output and the A-wtd S/N ratio is some 6dB wider via the 10ohm Marquis at 86.5dB. It's a colourful performer! PM

Maximum output (<1% THD into 47kohm): 4700mV
Max. power output (<1% THD into 25ohm): 135mW
Output Impedance (20Hz-20kHz): 6-8ohm (pre, 3.2kohm)
A-wtd S/N ratio (re. 0dBV): 86.5dB
Distortion (20Hz-20kHz, re. 10mW/0dBV): 0.43-2.0% / 0.013-0.05%
Frequency resp. (20Hz-20kHz/100kHz): –11.5dB to –0.1/+0.06dB
Stereo separation (20Hz-20kHz): 69-94dB
Power consumption: 3W
Dimensions (WHD) / Weight: 150x250x170mm / 3.6kg
Price: £6000