If it turns out that the linear supply sounds a whole lot better, then I've told my friend that can he can have that one, because his speakers are far more demanding than my Cornwalls.
I would actually expect a decent SMPS supply to be able to deliver more current:
SMPS Power Supplies vs Linear Power Supplies Per Linn
"I'd like to answer your question firstly with a bit of background information about the larger power amplifier supplies and why a SMPS is benefitial in that case, as I think it will aid the understanding overall, and then move onto the specifics about SMPS for line level products.
The nature of a musical signal means it doesn't present a constant load, particularly in a power amplifier where large amounts of current are provided to move the drive units. A linear power supply relies on the smoothing capacitors on its output to provide the power that the circuits use, which works well enough for a constant load, however as the load draws power from these capacitors they are only getting topped up at mains frequency, 50 or 60 times a second depending on the local mains supply, so as the load increases the capacitors are unable to keep up with large demands at higher frequencies than 50 or 60Hz. The signal created by a kick drum typically used in rock/pop music is a damped impulse, containing large amounts of energy at significantly higher frequencies than 50Hz which causes the smoothing capacitors to start discharging, and the power rails to droop, increasing the likelyhood of power amp clipping.
A switching power supply not only tops up the capacitors at its switching frequency, in the case of our power amplifiers that is in the region of 50,000 times a second, but it also has a feedback network that is monitoring the power rails being delivered. Meaning that the power rails are significantly less prone to mains related pumping (which will eventually occur with a switching supply if you increase the load on it far enough, in the case of our power amp supply that is when delivering over a kW continuously) and the power rails are significantly more stable.
In the case of a line level product, the loads are more constant so they are less susceptible to pumping in the fashion described above, but the circuits are still susceptible to the mains frequency and the harmonics thereof, all of which are audible frequencies, getting onto the power rails and signal ground. The devices within the audio circuits whether it be digital or analogue need to rely on their own power supply rejection ratio and bulk storage capacitors to prevent these frequencies from interfering with the audio.
A well designed switching supply won't introduce the mains frequency to either the power rails or the signal ground and will filter the rails such that the impact of the inaudible switching frequency is minimised (our switching frequency for line level products is 132kHz). It is much more practical to filter out high frequency noise than it is to filter low frequency due to the physical sizes of the components required to perform the task in hand.
The very nature of any switching supply means that it needs an input filter to prevent emissions getting onto the mains, this filter also doubles up to protect the power supply itself from noise that is already on the mains. In the majority of cases a linear power supply doesn't feature any form of filtering against RF noise which will then get through the mains transformer and into the connected circuitry.
