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In Reply to: RE: Stunning performance with Peaktech ( velleman ) Linear PSU powering p24 & p4 posted by etiennelemay@gmail.com on August 11, 2010 at 17:13:11
Hi Etienne,
I stumbled on your post and would like too suggest too take care in chosing the right picoPSU model.
Chosing the right picoPSU model (which leaves the 12v line untouched) is important.
Not al picoPSU’s are made by the same concept. Some picoPSU models leave the 12 V line untouched and pas the 12V line straight on too the MoBo. But there are other picoPSU models that don’t leave the 12 V line untouched and also regulate the 12 V line.
I first bought the wrong picoPSU model. A PW-200-M w/P4-ATX. This model also regulates the 12 V line which results in almost no sound quality improvement over a standard ATX switching PSU with ‘smoothing caps’ on the P4. It’s not worth the trouble to change a ‘smoothing capped’ ANTEC ATX PSU for an picoPSU PW-200-M w/P4-ATX IMHO.
I know of at least one picoPSU model ( 150-XT ) that leaves the 12 v line untouched. This model passes the 12 V line straight on too the MoBo. But there may be more picoPSU models that leave the 12V line untouched.
fully AOB optimized cMP2 PC -> Lynx AES16 -> XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
Follow Ups:
It's done!!! Hurray! That upgrade was easyer than I though.
Sweet now my cMP^2 has 1 Velleman PSU which powers the P4 and the P24 and 1 GD that power the USB port and the HDD.
After just an hour of listening (not fully burned in yet) it's really stunning! I'm completely amazed!!
Can I leave the Velleman PSU running 24/7? Is that safe? I'm not 100% confident....
One other thing. Should I try to feed my PC exactly 12v or I should try to lower the voltage as low as I can?
Thanks for all your help!
Etienne
Hi Etienne,Indeed adding linear PSU’s to power the P4 and P24 pins on the cMP MoBo is really easy.
Keep in mind though that the 5 V and the 3.3 V line are still powered by switching circuitries on the picoPSU. Although I expect the switching distortion being lower in a 12v DC picoPSU than in a 230 AC Volt ATX. But I’m no expert in this matter.
The 5 volt seems to be the most critical power-rail, so that is why the real PSU diehards here on the forum, also power the 5 volt rail with a linear PSU. But as you can read on the forum, unfortunately that is not so easy at all. I still haven’t found an simple and easy way too do that.
I see no real logic in crippling your picoPSU / Mobo combo through lowering the voltage untill such a low level that it stops functioning. It’s designed to work with 12 V. Lowering the voltage will only make life harder for correcting and adjustment circuitries on the picoPSU and/or MoBo.
Like Gstew already suggested: do some experimenting what sounds best: the GD or the old ATX for USB & HDD.
Also do some experiments with your earthing arrangements. Since you have more boxes now earthing arrangements are also important to pay attention too.
First try too discover what the correct position is of your AC 230 Volt plug into the mains power socket. You should chose the position which results in the lowest possible ‘AC residue voltage’ on the outer housing of your Velleman. (put your multimeter on AC-position. And than check which plug position in the 230 AC socket, results in lowest possible ‘AC residue voltage’ on the outer housing and a REAL EARTH (!) connection.)
Also check your DAC, Amps, ect if they are also connected too the mains with the 230 V AC plug in a position that will result in lowest ‘AC residue voltage’ on the outer housing.
(grrr :-( Third Edit )
I forgot to mention: when you do these measurements, you first have to connect the equipment you want too measure, to a non-earthed AC socket and disconnect from other equipment. Make notes of which 230 AC V pin is the ‘hot’ / ‘live’ pin.
After you found out what the position is which results in the lowest ‘AC residue voltage’ on the housing, than re-connect to the aerthed 230 AC wall socket you normaly use. But… be sure too connect it again with the ‘hot’ / ‘live’ pin in the same position as you discovered while doing the measurements on the non-earthed AC socket. Hope this is a somehow a clear explanation :-)
Also like TheoB discovered (and Cics also suggested) earthing and earthing arrangements are also important. I discovered this too. When I wired together: the outer housing/ case of my DAC too the outer housing / Zahlman case of my cMP. The stereo-image became really much better. So do some experimenting by wiring together the outer housings of some / all of your ‘boxes’ and listen for improvement.
For safety reasons al outer cases must be aerthed inside the box. Thus al housings can already ‘see’ each other through these earth connections. Strangely enough though, sometimes there is still sound quality improvement when connection the outer casings together with an extra wire.
In my setup there is improvement when I connect the housing of the DAC and the PC-case together. Connecting other cases together makes no SQ difference in my setup.
Though when listening for improvements, beware of placebo-effects!!
I personally believe that much of the so called ‘break in improvements’ are placebo-effects and/or adjustment too the new sound.
(if there is any new sound or real sound quality improvement at all !)I switch off the Velleman, since it saves energy. I also always switch it of when leaving the house. Thus avoiding risk off overheating and fire when I’m away from home.
fully AOB optimized cMP2 PC -> Lynx AES16 -> XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
Edits: 08/19/10 08/19/10 08/19/10 08/19/10
Hi
Thanks (again!) for the nice reply (and your multiple edits!!)
By the way, I live in Canada so i'm on 120V.Thanks for all the detailed explanation about earthing, I'll sure get into that someday. For now I'll enjoy my current improvement. Plus, I'm not 100% sure I understood what you meant about the "position" of my plug into my main...
(Edit #1)
Unfortunattely I won't be able to test the audio difference between the GD and the Antec. I did some cable management to the Antec and I only left the P24 the P4 connectors. :-(
(end of Edit #1)This might be a weird and stupid question but are we 100% sure that the Velleman is a linear PSU? I looked at the operating manual (which is super small) and it doesn't really mention it. I was really suprised to find a linear power supply that cheap. Every other linear PSU were over 2 or 3 times (or more) the money. The sales guy was also sceptical that the Velleman (Peaktek) was linear, he thought it was a switching mode power supply.
Anyways, it was still a major improvement on my system and I'm super happy I made the move! I was really excited to get back from work today! :-)
Thanks again for your help and to everybody who made this possible!
Etienne
Edits: 08/19/10
Hi Etienne,
A while ago Cics pointed me at the Velleman linear PSU. It’s indeed very cheap but with good specs. However I don’t know how trustworthy those specs are. Chinese do everything to sell there products. Which often means: also bending the truth a little. I hope that Velleman will live up too there reputation.
Too make you feel comfortable I shot a photo of the inside. You can see the transformer coil. So it’s a linear one.
Enjoy.
fully AOB optimized cMP2 PC -> Lynx AES16 -> XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
Edits: 08/20/10
One again, hanks for the answer and for the picture!
So it is linear after all! Yay!
Good to know!
Etienne
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