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Hotrodding the X-Fi: A Layman's Guide (No 56k) - Page 116

post #1726 of 2194
I currently use LME49720, is there any other opamp I should try? Planning to try either LT1364 or LT1361
post #1727 of 2194
Quote:
Originally Posted by Apocalypsee View Post
I currently use LME49720, is there any other opamp I should try? Planning to try either LT1364 or LT1361
ad8620
post #1728 of 2194
Quote:
Originally Posted by qwerty009 View Post
ad8620
Hmm, its hard to get that opamp. What about LM6172? Or am I crazy to use that?

EDIT: After reading around, I think I wanted to try AD8599
post #1729 of 2194
Quote:
Originally Posted by qwerty009 View Post
ad8620
AD8620 expensive here, USD$18++...
post #1730 of 2194
Quote:
Originally Posted by Apocalypsee View Post
EDIT: After reading around, I think I wanted to try AD8599
I've got AD8599. I like it, although I can't compare it with anything but stock opamps.
post #1731 of 2194
coolkwc - Panny FL capacitor is nowhere near to be found, not even as discontinued ones, on Panasonic site:
Capacitive Products - Leaded Electrolytic
Hence it is fake cap.

Quote:
1.) I replaced C72, C74, C75, C43 -->Rubycon MBZ 1000uf 16v
I recommending different capacitors (before you ask, check my thread first) but still a good work. Maybe 1000uF is overkill, but... good.

Quote:
C46, 91, 107, 119 -->Rubycon MBZ 1000uf 10V
Also good, but I would go with 6.3V and Panny FM as it have far better ripple specs at the size. Rergardless, anything is better that known failing bad caps Jamicons.

Quote:
and C16 -->Panasonic FL 680uf 4v...do you think my mod is suitable? any inappropriate? well, i'm poor, those cap i all taken from the mobo and GC...
Yep, reasonably good, except for these questionable caps. Especially in the C177, C16 and C46 positions where it matters. A Samxon GD 470uF 6.3V if a miracle for the last two positions.

Quote:
2.) Since you said that the recommended cap ripple value is around 1500mA, but the application design by using Sanyo Oscon SVP 330uf 16v has a rated RMS ripple current 4720mA as well, how you going to explain it?
I would urge you to re-read the PDF again You got it wrong and it was explained why and how... it all depends on the powering voltage, switching frequency and impadance of used coil. For components present on X-Fi is a surprisingly mediocre cap the best.
Oscons cause huge voltage spikes there. Because of their super-low-ESR nature and very high ripple currents...

Quote:
3.)In this case the input ripple voltage would be 140 mV and the RMS ripple current would be 1.5 A. The maximum voltage across the input capacitors would be VIN max plus delta VIN/2. The chosen bulk and bypass capacitors are each rated for 25 V and the combined ripple current capacity is greater than 3 A, both providing ample margin. It is very important that the maximum ratings for voltage and current are not exceeded under any circumstance.

I think the ripple current you said was came from here, rite? Ok, if the RMS ripple current is 1500mA, that means we suppose should use the cap that can handle at least or above this current rating? is that any wrong?
No, this is dangerous and wrong oversimplification that does not take into the account the exisiting components on the X-Fi. Few quotes from the PDF:

Quote:
The ESR is important because along with the inductor current it determines the amount of output ripple voltage.
Quote:
Consider the relationship between the desired closed loop crossover frequency of the design and LC corner frequency of the output filter. In general, it is desirable to keep the closed loop crossover frequency at less than 1/5 of the switching frequency.
Quote:
In Figure 28, the TPS54356 shown with a single 100-µF
6-V POSCAP as the output filter capacitor.
Quote:
Calculating the RMS ripple current in the output capacitor using equation 16 yields 156 mA. The POSCAP 6TPC100M capacitor selected is rated for 1700 mA.
Quote:
In Figure 29, the TPS54356 shown with two 180-µF 4-V special polymer dielectric output filter capacitors(C2 and C5). The RMS ripple current in the output capacitor is the same as before. The selected capacitors are each 3.3 A.
Quote:
The special polymer electrolytic capacitors used in this design require that the closed loop crossover frequency be lowered due to the significantly lower ESR of this type of capacitor.
Quote:
bro, comment on it, just give any suggestion or correction or even criticism, i will please to hear it, thanks...
Well, I think everything is written long time ago there. Since most (if not all for the time being) of the X-Fi modifications are simple opamps and capacitor replacements/removal/shortage and no-one is modyfying the frequency of the regulator used to power the main X-Fi chip, then Os-cons is a bad bad bad idea. Around page 54 of this thread I tried it too myself.
So, unless you want fiddle with the frequency used, I suggest you use around 1000uF 6.3V capacitor with reasonable specs (not too low ESR, not too high ripple). It could be better even bellow average one - eg. lower specs Samxon GD would probably yield better results in voltage stability (read output ripple) that the Samxon GC 1000uF 6.3V I used.


apatN - yes, never.


Apocalypsee - Well, that's the beauty of it. Ask 20 hifists about witch opamp they would recommend, get 20 recommendations

AD8599 is awailable in only SOIC package, but that is ideal for X-Fi. LM4562 is either as SOIC, or as DIP8 - witch is great.

AD8599 also could be "slow" for electronic music/game SFX... but I quess personal preferences and the rest of the setup play much major role that these opamps.
But I like the AD8599 as replacement.
There is also another reason for AD8599, not widely known. When using 5.1 output from the card (eg. utilizing most of the opamps) the LM4562 draw a 500mA, while AD8599 only 450mA. Even the difference is small, it could affect good the circuit that lack a big capacitor somewhere in middle of these opamps so the actull current draw from any / all of them does not affecting the nearby ones much.
That is why C46 position is critical.
Adding aditional voltage filtering cap is a good idea.
Also little cooper heatsinks on these opamps and on the DAC would help to
a) add shielding
b) cool the components down, hence minimizing the noise
post #1732 of 2194
Quote:
Originally Posted by BigSurSpoon View Post
If you don't want to replace the power filter capacitor with the BG 16v 2200uF, what would be some good alternatives?
Quote:
Originally Posted by coolkwc View Post
Well, i use Panasonic Low ESR 680uf 4v solid cap, work perfectly...
See following two old posts, ultra-low ERS capacitor considerations (solid-polymer, ie., OSCON, NPCAP, PXA, SP-CAP, etc.) feeding X-FI CA20K1. (C161, SB0550 or C177, SB0460)
http://www.head-fi.org/forums/3269637-post1295.html
http://www.head-fi.org/forums/3269940-post1296.html

Component/Location Reference Pictures:
SB0460:
X-FI-MOD-029b - eSnips, share anything
SB0550:
X-FI-MOD-109 - eSnips, share anything

Holland
- thanks for the ethical support!
http://www.head-fi.org/forums/4198481-post38.html

Trodas,
- request you unlink my work from your Imageshack/past posts
- information is not complete without my comments and must be linked to original location(s).
http://www.head-fi.org/forums/3773655-post27.html
http://www.head-fi.org/forums/4165909-post31.html
post #1733 of 2194
Keep up the good work.
post #1734 of 2194
Quote:
Originally Posted by trodas View Post
coolkwc
Hence it is fake cap.
i took it from ASUS mobo, i don't think it was fake cap, and i can find FL series in ebay, only got high capacity...but i can't explain why it was not in Panny product list even in discontinued list, its weird...

Quote:
Originally Posted by trodas View Post
coolkwc
Oscons cause huge voltage spikes there. Because of their super-low-ESR nature and very high ripple currents...
ermm, i saw you used Oscon in the C177 before, how is the voltage spikes measured? i just wonder the voltage spikes you mentioned always...thanks
post #1735 of 2194
Asus is well-known for using fake brands of caps and even fake caps. Seen this only too many times...
The reason why Panny FL is not into Panny caps list is clearly simple. They did not made them. It is that simple. I can show you many examples, but this is a X-Fi thread, not fake caps thread

Yes, I used Oscon as C177 before, and quess what. The voltage is nowhere as clean, as with the Panny FM 470uF 16V or the Samxon GC 1000uF 6.3V ... spikes are measured with scope, of course. DMM is useless for measuring at mainbords, because in case of AC voltage or DC with spikes/noise it always only show the effective average, where you are most interesed about the noise, spikes and/or the highest spike to know, what is the absolute max voltage on the cap, so what voltage cap you can use there. That is why I in my thread took the time and measure ALL the caps on X-Fi for their max voltages
post #1736 of 2194
Quote:
Originally Posted by trodas View Post
Asus is well-known for using fake brands of caps and even fake caps. Seen this only too many times...
The reason why Panny FL is not into Panny caps list is clearly simple. They did not made them. It is that simple. I can show you many examples, but this is a X-Fi thread, not fake caps thread

Yes, I used Oscon as C177 before, and quess what. The voltage is nowhere as clean, as with the Panny FM 470uF 16V or the Samxon GC 1000uF 6.3V ... spikes are measured with scope, of course. DMM is useless for measuring at mainbords, because in case of AC voltage or DC with spikes/noise it always only show the effective average, where you are most interesed about the noise, spikes and/or the highest spike to know, what is the absolute max voltage on the cap, so what voltage cap you can use there. That is why I in my thread took the time and measure ALL the caps on X-Fi for their max voltages
lol, just link him to your cap thread on tpu, i think he'll get the idea.
post #1737 of 2194
Thread Starter 
dammit my x-fi doesn't work when i install my Radeon video card. is there some kind of weird incompatibility between the SB0460 and certain motherboard/video card combos?
post #1738 of 2194
Quote:
Originally Posted by cotdt View Post
dammit my x-fi doesn't work when i install my Radeon video card. is there some kind of weird incompatibility between the SB0460 and certain motherboard/video card combos?
no, none that i know of.
irq issue maybe?
post #1739 of 2194
Thread Starter 
Quote:
Originally Posted by Random Murderer View Post
no, none that i know of.
irq issue maybe?
i tried manually assigning the IRQs and tried all the different PCI slots but nothing works. the computer would not even turn on. Audigy2 works fine though, but not X-Fi.
post #1740 of 2194
Quote:
Originally Posted by cotdt View Post
i tried manually assigning the IRQs and tried all the different PCI slots but nothing works. the computer would not even turn on. Audigy2 works fine though, but not X-Fi.
how much ram do you have installed?
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