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In Reply to: RE: P24 current measurements. posted by hfavandepas on November 18, 2009 at 08:56:17
Mark,
I strongly recommend to cut (or just mask if you will) the PCI traces to Juli@, unsolder the regulator U1 (no big deal, really) and supply it externally with clean 3v3 and 5v (remember that only the analog part of Juli@ plus one or two chips consume very little current on the 5v rail, the vast majority are 3v3 consumers!) - you're isolating Juli@ from all interferences, noise etc. coming from the mobo's voltage rails plus supply good quality power in addition - little effort gives you maximum return! In terms of return on effort invested as well as in achievable sonic improvement, I'd say this is clearly priority #1! The results at least in my system (when also adjusting voltages externally supplied to exactly match those on the mobo) were in order of magnitudes above most others I had done.
Best,
Robert
Follow Ups:
Hi Bertel,Change off plans.
Since Gene_ showed how too power up the MoBo manually, my efforts to improve power supply to the cMP2 PC (PSU improvements part 3), will again be directed back to the 3,3 Volt and 5 Volt rail of the P24 connector.
In theory it now looks strikingly simple to realise a full linear power supply for the P24 connector:
- power the 3.3 Volt, 5 Volt and the 12Volt rail with a good Linear PSU or battery;
- also power the +5Volt stand-by on pin 9 (purple wire) to activate the Power Control Circuit on the MoBo;
- also give some -9 <-> -12 Volt (bleu wire) for starting the serial controller on the GA-G31M-ES2L MoBo;Switch manually (or with a relay) a +5 Volt signal (PWR_OK signal) to pin 8 (grey wire) and there you go. The PCC will start the MoBo.
Gene_ proved that giving the PWR_OK signal on pin 8 (grey wire) is not time critical at all.
It doesn't have to be done within 500 milliseconds as the ATX formfactor suggests.
The PWR_OK signal can be given at any desired time.
When there is power present on the 3.3 Volt, 5 Volt and the 12Volt rail and the Power Control Circuit is active (+5 volt on pin 9 (purple wire)), the PCC will start the MoBo.I tested this in my setup with the ANTEC Earth Watts and it works.
Giving the PWR_OK signal manually on pin 8 (grey wire) at P24 connector. cMP2 project. Gene_ already showed that it also works in his setup with a combo of linear PSU’s and battery power.
So when I have sold my Lynx L22 card, I will buy myself from that money, a very nice and decent linear laboratory PSU with two (3.3V, 5V) or may be even three (3.3V, 5V, 12V) quality DC outputs. And PSU improvements part 3 will be realised !!
A hybrid Power Supply solution on the P24 connector will no longer be necessary. A full computer linear power supply on the P24 connecter will than be realised. (with again many thankx to Gene_)
fully AOB optimized cMP2 PC -> Lynx AES16 -> XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
Edits: 11/25/09 11/25/09
...power the 5V/3.3V rails directly with clean linear supplies, and the rest with your Pico PSU. Just buy or build the 5V/3.3V linear supplies, and you're good to go!
"We should no more let numbers define audio quality than we would let chemical analysis be the arbiter of fine wines." N.P.
Hi ‘ForgotPassword’,
Thank you very much! I didn’t think of that.
Indeed, the picoPSU is still very useful. The pico can provide the -12V and do ‘the talking’ too the Power Control Circuit to start-up the MoBo the easy way.
May be the shut-down process also could be handled nicer with the help of the pico.
I think your tip is also a good idea for battery users. I read that battery users also struggle with providing the voltages which do ‘the talking’ to the Power Control Circuit.
I hope that these threads inspires other inmates too, to come up with ideas to realise a full linear power supply the easy way.
Your tip made the setup for a full linear power supply again more simple and more easy (read: more ‘DIY-doable’).
Thank you.
Mark
fully AOB optimized cMP2 PC -> Lynx AES16 -> XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
Pico surely makes life alot easier for novice DIYers like me. I believe it also helps SQ indirectly by reducing the number of relays/power switches in the power supplies.
On a side note, don't hesitate to aim for "overkill" capacity when building these supplies. I built the the 5v, 12v, and 3.3V supplies with 130VA trafo/LT1083, ~130VA/LT1084, and 30VA/LT1086, respectively. You could use a smaller transformer for the 12V supply, though. My 12V supply is excessively big only because it's the same one I used to power the Pico in its full glory.
"We should no more let numbers define audio quality than we would let chemical analysis be the arbiter of fine wines." N.P.
Hi Robert,
You make things easy. Thank you for the advice. So option 1. it will be.
1. Only the Juli@ soundcard (with PCI power supply traces cut). (bypassing the MoBo)
I think it’s also the most cost effective one.
As other inmates reports very good results with battery power, I’m even prepared to take a close look at ‘battery power’. :-)
Mark
fully AOB optimized cMP2 PC -> Lynx AES16 -> XLR AES/EBU -> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
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