Originally Posted by
MrRadish
I feel like I'm drifting off topic answering this, given where the rest of the thread has gone :-)
I've had or have some Maplin test bench LPSU, HDPlex LPSU, iFi iPower SMPS, Russ Andrews PowerPak 2 SMPS, Longdog Audio LPSU, cheap Maplin SMPS and SoTM mbps-d2s battery pack. I used them to power either a PPA v2 card, SoTM PCIe card or a Hi-Face EVO converter. I didn't have them all at the same time, but the Maplins and HDPlex provided a constant reference point. I had two of most of the units to handle 5v and 9v, but found the results (comparisons) were the same regardless of what I was powering. I mostly swapped them over in pairs, where feasible.
The cheap Maplin SMPS was awful, noisy and just yeeuch...
The Maplin test bench were mediocre with poor transparency, poor liquidity and a slight treble roll off, though they were reasonably musical and had decent bass weight.
The HDPlex was almost identical to the Maplin LPSU but a little more rolled off in the treble and slightly more musical. Pleasant but low-fi.
The iFi were technically fine (no roll-off), reasonably transparent and didn't draw attention to themselves, but they weren't particularly musical. I just got bored listening to them.
The Russ Andrews SMPS was beautifully sweet, open and transparent with excellent treble purity and very musical, but slightly lean in the bass. I only had a 9v one of those, so that was testing with the EVO.
The SoTM battery pack was a good all-rounder with no deficiencies and reasonably musical, but not as transparent or enjoyable as the RA (testing with the EVO).
The Longdog supplies are the best of the bunch, with a musical, liquid, well-balanced sound that doesn't draw attention to itself. I don't know if they're as open as the RA, but it's not something I can compare any more.
I should also add a couple of riders:
1. All my testing used substantial mains filtering or regeneration. The SoTM battery supply's main strength is that it doesn't need any of that (for itself), so the other supplies had a helping hand.
2. I've used both SMPS and LPSU ATX power at various points and on one occasion devoting an AG1500 just to the SMPS ATX unit and running the USB card and everything after that from a different regenerator produced excellent results. That was with the Maplin LPSU in place, so the quality and cleanliness of the AC feeding these supplies seems to matter a lot.