lpv said:
surely the salesman was aware of AEX 2 volts output...
The output of the AEX is about 1 volt, the retailer did not 'consider the AEX to be hi-fi'.
This was several years ago and the setup was as follows, Flac files on a Macbook, over Airplay to a Mk 2 'plug in' AEX, then either via Toslink to the M-Dac then analogue to amplifier or analogue direct to the amplifier. There was no direct switching, the optical and analogue cable into the AEX were switched by hand with the amp muted.
With the M-Dac in 'dac mode', the output was clearly much higher than the AEX, so the M-Dac was switched to 'pre-amp mode' and the output turned down. A test tone (1kHz sine wave) was played by the Mac and the voltage, in millivolts, measured at the speaker terminals using my old Fluke digital multimeter, the output of the M-Dac was adjusted to be the same as the AEX.
The switching was done blind, informally so, but I was never sure which combination I was listening to, given the delay, about 5 or 6 seconds maybe, It was virtually impossible to tell which was which.
The test had several flaws, the use of Airplay with it's ALAC compression, the time taken to perform the switching, the poor jitter performance of the AEX etc, but the retailers only comment was that the M-Dac sounded better in 'Dac mode' rather than 'pre-amp mode'.