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In Reply to: RE: cPlay - the open source high-end audio player using ASIO posted by cics on May 05, 2008 at 12:31:58
For anyone considering a linear PSU + picoPSU
In the process of optimizing the power for the P24 connection, I did some current measurements on the 12 Volt DC powerline that feed the 12V Micro Power Supply from Mini-Box. Model: PW-200-M (200 Watt).
In some posts current draws on the 5 V lines of the P24 connector off over 4 Amp’s are reported (On a cMP optimized computer transport). So just to be sure that enough power can be delivered, I bought an 200 Watt version (PW-200-M) and also an linear bench/lab PSU capable of delivering up to 6 Amps at 12 V.
After measuring the current into the 12v Micro PSU the whole seams a little over dimensioned.
During boot-up the current to the 12V Micro Power Supply reads between 1.6 to 1.95 Amps with one short peak on 2.1 Amp.
During playback (or idle) it's 1,28 Amp. At a constant value.
This value is only a little influenced by bus speed, monitor resolution / color settings, type of sound-card. Ect. The LynxL22 draws 0,1 amp more than the Juli@ (without the analog part)
So in my cMP-setup the P24 pin uses/consumes:
- At start-up: 1.6 – 1.9 Amps. 1 peak at 2.1 Amps. x 12 Volt is about: 20 - 25 Watt’s
- when playing / idle: 1.28 - 1,35 Amps. x 12 Volt is about 15 – 16 Watt’s
If anyone considers buying a picoPSU for the P24 connector:
the smallest picoPSU version of 60 Watt, should be enough (for a cMP optimized PC).
Also a small linear bench / lap PSU (with low ripple specs) capable of delivering 2,5 Amp’s should be enough.
PSU-wise my cMP setup now looks like this:
- P4 pin: 1 linear bench / lab PSU output: 12V DC / 2,5 Amp max
- P24 pin: 1 linear bench / lab PSU output: 12V DC/ 6 Amp max -> Mini-Box PW-200-M. (with smoothing caps on all 3 voltages (3,3/5/12)
- USB, HDD, DVD, etc: ANTEC AW 430
Pin 16 (PS_ON) on the ANTEC P24 connector is grounded to pin 17 to start the Antec. The P24 pin isn’t used to feed the MOBO P24 connector. (The picoPSU now does that). Only the ANTEC’s molex connecters (5V + 12V) are used to feed USB, HDD and DVD as explained in Cic’s AOB manual)
Sound Quality <-> costs
ANTECH AW 430 PSU costs about 47 euro (in The Netherlands)
A picoPSU costs 37 euro + 30 euro for linear bench / lab PSU = 67 euro (in The Netherlands)
IMHO the extra 20 euro’s are definitely worth the extra costs.
I hope the placebo-effect is not fooling me but I think the picoPSU + Linear PSU sounds better than the ANTEC AW 430. Not a gigantic difference, just a little better. More space, better imaging, better treble , etc. Everything a little better.
And…… as with the power optimization for the P4 connector: its very, very easy to implement. Anyone can do it in 15 - 30 minutes.
Are there any other inmates that can comment on SQ-improvements when using a picoPSU (versus a 'normal' swithing ATX PSU) ?
Mark
N.B. How the currents measurements were done:
1 linear bench / lab PSU -> multi-meter -> Mini-Box PW-200-M.
cMP2 optimized as per Cics recommendations: all BIOS optimizations done (no EIST function) + all software + min logon. GigaB G31M-S2L, E7300, Core Speed: 840 MHz (140x6), FSB 560 MHz, 1Gb Kingston HyperX, at 3-3-3-5, FSB not undervolted, CPU GTLREF ratio at 0.65, CPU Voltage at 1.0000V (just enough for allowing passive cooling)
LynxL22 dig i/o XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
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