Richard12

Both smps and Lps will be "quit" when passive cooled. In case of fans for cooling (as common on ATX smps) you will hear the fan noise only. Pico psu are quit! When using a good LPS (as i.e. HDplex) directly connectd to mb, ripple will be even smaller as with the DC-DC converters from i.e. Pico or HDplex which need to be used with 230VAC smps adapters with 12 or 19 VDC output. I have no audiofiel comparison between full LPS and DC-DC converters powered by smps adapter or powered by LPS with 12 or 19V DC. But LPS are rather expensive compared to the DC-DC converters and at least from price perspective they should sound clearly better. If they do??

OK, I did not read all threads but did not notice noise issues with Pico psu. The only reliable contribution I found was from jonnyguru Pico PSU Round Up Review. Jonny's measurements show low ripple and no noise issues for Pico psu. The same results as my measurements for HDplex DC-DC psu (measured with both single ended as differential oscilloscope probes) Audible noise (humm,hisses etc) has been noticed but are related to improper grounding. When using a 12V adapter (or any other adapter) attention shall be paid to grounding aspects. The adapter may interrupt the grounding wire from the wall socket outlet to the metal pc housing. Also the minus of the DC supply (5V- 12V) shall be connected to the metal housing, what is normal for ATX smps supplies. Pico as well as HDplex DC-DC converters are very well suitable for pc-audio. Hopes this helps?

Hi, why do you state that Pico is noisy? And do you really mean noise (hf spikes stc) or ripple? Did you found any reference to reliable measurements? If yes pelase can you share these reference. I'm interested. I'm using a HDPLEX DC-DC convertor (what is more or less comparable with Pico system) and am happy with it. It is powered by Dell laptop supply with 19,5 Vdc output and works fine. The measurements I performed showed no noise and small ripple. Very acceptable and a cheap solution for noise free supply. Far better as the noisy ATX smps supplies . See also http://www.computeraudiophile.com/f10-music-servers/hdplex-linear-power-supply-21175/

In the mean time I performed some noise and ripple measurements at HDPLEX 160W DC-ATX Power Suppl, which pleases me very much! No noise was measured at all (hf spikes) as are heavily present as common modes disturbing signals in normal ATX smps. Ripple was about 40mV at 12V and 10 mV at 5Vrail. Pretty good at all! No need for separate 5V suply of my SSD anymore.

Just want to share my experience with HDPLEX 160W DC-ATX Power Supply. I just installed HDPLEX 160W DC-ATX Power Supply this weekend wich is supplied by Dell 19V laptop adaptor. Also performed some noise measuements on the 12V and 5V output with my scope. The way of measurement is basically incorrect because it shall be performed with differential probes due to common mode injection. I only have single ended probes but when compared with the standard smps ATX supplies it's a big improvement in noise. Next week i hope to repeat measurements with differential probe to obtain from collegue. The most important however is the improvement in sound! More detail and space are clearly noticible. I preferred to try the HDPLEX above the pico due to the wide voltage input range and the availability here. The HDPLEX has a heatsink and has to be mounted on a steel frame. That's a disadvantage in way of location and installation compared to pico, but for me it feels more solid to dissipate the heat this way. Just curious about anyone's else experience with DC/DC converters.