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RE: P24 current measurements

Greg,

thank you. Yes, I'm completely with you that powering every power rail separately is a good idea - it might be a bit of overkill, but separation and elimination of interference and cross-balancing issues (quite a concern in "standard" ATX power supplies) will help bring the various components even more "at rest" and let them play as easy and effortless as possible. When I have swapped my Lynx card with Juli@ and powered it separately, P24 "only" has to power MoBo and memory (still and awfully complicated task), that'll help. I'm planning on using completely separated supplies (i.e. battery packs) for every voltage line anyway, including thorough regulating plus filtering caps - more to follow as I progress ;-)

Regarding booting with -12V and 5V standby turned off: You'd loose your bet ;-) PS for P4 and P24 has been my special field of interest for the past weeks, and while P4 is easy, P24 needs quite some attention... As you might know, ATX standard requires a proper and quite stict power up scheme (more details can e.g. be found here: www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf). 5V has to be there in the first place for the computer's power switch to have the MoBo's power control circuit (PCC) start the sequence, hold low the formerly held high 5V "Power_On" line (the green line on P24) to have the power supply ramp up the three main voltage lines and after successfully doing this issue the Power_Good signal (5V, the grey line on P24). This all has to be done in a corridor in a 100ms range with specific ramp rates, and I found the Gigabyte board be rather strict at that - I tried for weeks to emulate that timing and ramping manually (with switches and caps etc.) but didn't succeed, you need some kind of power management component to take care of this. I'm currently looking for someone to build such a power sequencing model from readily available components like Actel's Fusion or Linear Technologies' LTC2928 (cost currently quoted at 10-15k and above for developing that...), but in the meantime as a workaround just power up with my regular ATX PS (Antec) and then switch off the special rails not needed and switch over the main rails to battery power. Quite rough a method, I know, but works well for 12V and 3.3V for the time being, but still stability issues with the "workhorse" 5V rail. Will keep you updated once I have gathered more experience and details. Nevertheless, 5V standby and -12V line is a must to be present at startup, otherwise MoBo's PCC will not power up.

Regarding my P4 battery PS: No special timing etc. issues have to be taken care of here, powering P4 is pretty easy and straightforward as many have shown us here before (many thanks for their respective guidance and information!). In my case I power this with a pack of 3 boards with 5 high-quality 1.2V/1.8Ah NiMH cells each, i.e. 18V/1.8Ah (recharged by a transformator fed into the central control unit, all of these modules are manufactured by a small local electronics company). Since the current draw is low at ~350mA during playback, this is good for a 4 hour listening session (I usually don't have that much time in one go anyway...). Power then is fed into a voltage regulator which brings it down to precisely 11.94V as measured to be optimal by Bernd and confirmed by Theo recently. Since the regulator is designed to be quite "slow" and "weak" on purpose and thus is very forgiving, large caps can follow - I run the power into 5 x 10kuF Mundorf caps followed by a 47uF cap as quick buffer and a 1uF one as bypass (I am extremely positive about the Mundorfs, can't praise them enough). this setup works like a charm without any hassle for me. While the sonic effects were rather subtle from the start, I feel it overall added transparence and clarity and ease of playing, especially in midrange and upper bass - to my ears it rather sounded a bit as I could here the processor working now without the limits of a rigid, tight and polluted power supply as before, but that's what I wanted to hear for sure ;-) That's more or less a similar setup I'll try to follow with P24 too, will let you know once I get there (will require mighty PB cells instead of the NiMH for the 5v rail though).

Mushkin memory has been a recommendation by Alfred/sonics, so he's the one to both take the credits and comment on that in more detail. Haven't done much comparison myself - I almost exclusively play 16/44.1 WAV files upsampled to 24/192, had ValueRam 256MB before, swapped that with an "original" HyperX UL stick w/ 512MB which brought significant improvements to me , but still swapping that to the 1GB Mushkin stick made things even more "right", beautiful and in place - for me quite a substantial improvement. I started with SPD in BIOS set to "Auto", CPU-Z showed it had clocked itself in at 4-3-3-7, so the only thing I did was lower the first value (cycles) to 3 which had an unexpectedly clear effect in bringing back lateral spacing and soundstage.

I think that's more than enough for one post now - thanks for your patience... ;-)
Robert



Edits: 05/04/09

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  • RE: P24 current measurements - Bertel 20:16:42 05/04/09 (0)

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