I agree, in general, that when a manufacturer or its representative is asked a direct question re. a change (such as use of a SMPS in the latest rev) & the subsequent answer avoids answering that question, that is not inspiring & leads the mind to think that something's being hidden. Maybe Almarg can press the issue at a later date when he's ready to purchase the HDP-5?
OTOH, SMPS power supplies for use in power amps have made good strides in the overcoming their output noise issues (that would increase distortion in the music signal path & wreck performance). We see this evidence in many amps today - Anthem's Statement M-1 mono, Benchmark's AHB-2, Belcanto amps, Jeff Rowland amps & the quite popular Ncore 1200 series amps - just to name a few. So, the technology of low-noise SMPS for audio applications is out there; whether DEQX has accessed it for their HDP-5 is the question that needs confirmation. It seems to be a reasonable assumption that they have but we know quite well where assumptions can lead us sometimes!! ;-) I also think that DEQX wouldn't do something regressive to ruin their highly touted HDP-4 & Premate by putting a noisy SMPS in the latest HDP-5 but who knows sometimes manuf do things that they think are progressive only to be told by the user community it's regressive....
I agree with Almarg that it's a safe bet to think that the HDP-5 has a quiet SMPS but reading/hearing it from the manuf rep would have a reassuring effect...