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RE: 'ranking' bypassing the MoBo

Hi Mark,

thanks for asking, I'll try to produce something meaningful on this issue - but I'm afraid the answer is not so straightforward... ;-)

Those of us that use the ESI Juli@ soundcard are in a very comfortable position when it comes to judging which solution is best - we unsolder the on-board regulator (5->3.3V), cut the respective traces on the PCI connector that carry in the voltages from the MoBo, feed Juli@ with clean 3.3V and 5v lines, and we're there. Juli@ has dedicated input/output points (kind of little "drill holes") that are wonderfully suited to take this external voltage supply.

I currently use a Juli@ too but have used a Lynx AES16 before. I have just taken my now obsolete Lynx in my hands and am looking at it - and especially when comparing it with Juli@, it's so §$%§& complex, and sadly this is a complexity that for the most part we don't need... It is an excellent piece of engineering, but I have a hard time identifying a good injection point for clean external power. Ok, there are SMD devices that look like input rail smoothing caps to me, labelled C50 and C51 (far left front side down at the PCI connector) and C52 (far right side), from what I see those could potentially do the job. You also had to take care of 3.3V and +/-12V. While poking around with my multimeter I saw that the PCI traces for these voltages are connected on the board but couldn't find chips that would share that connection. This of course needs more work and thorough analysis. But overall I would say that I do not see why it shouldn't be possible to power at least the whole card with clean external voltages. I personally would prefer cutting traces and soldering regs directly to the board. One next step would be to further identify regulators further "downstream" that do additional regulation, and eventually inject here. But this is open heart surgery ;-)

So since you say you could imagine using a riser card or something similar, i think that goes without bloodshed ;-) and should be easily doable - give it a try!

Do I understand you correctly that solution 3 would be to inject external power directly to the chips or parts of the soundcard? This is complex and challenging and would take a lot of analysis, including soldering then of course, but indeed would be very elegant, since then you maybe could shut of whole parts of the card that are not needed by cMP2 which would be great! But to call that "advanced" would be a massive understatement... ;-)

So apart from my estimation that solution 2 (at least for a start) is the only feasible and viable, here's my judgement od the effect of such an operation: when I did this to my Juli@, i.e. cut the PCI traces, unsoldered the on-board reg, connected clean 3.3V and 5v lines (battery plus cap/resistor plus reg) to the respective onboard connectors, the effect was not subtle at all but in an order of magnitudes. See, by doing that we (i) isolate the soundcard from all the powerline "pollution" on the MoBo, and (ii) feed it with dedicated clean power, thus massively increasing the stability and purity of its working environment. Ok, a card like the Lynx creates its own mess and pollution through its complexity and all that stuff that's onboard and working, so maybe the effect is a bit less, but you could think of adding caps and replacing regs (see Greg/Gstew mods to Juli@) and further improve.

So again: I would expect a top-of-the-ranking improvement. The more regs and caps you can replace or upgrade, the more you can add to this improvement. And as you already suggest: the first step is simple, get yourself a riser card, identify which voltages are really needed, and replace them with external ones (that's how Alfred/sonics had proceeded when developing the Juli@ PSU mod). in a next step you then could follw the way the current takes and improve upon its lines. Give it a try, IMHO you can't loose! :-)

Good luck!
Robert

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  • RE: 'ranking' bypassing the MoBo - Bertel 06:29:59 11/16/09 (0)
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