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Hotrodding the X-Fi: A Layman's Guide (No 56k) - Page 93

post #1381 of 2194
Quote:
Originally Posted by bichi View Post
TurtleTrax:
This is your lucky day. The "damaged" pad you show is not used. Just be sure it is left "open..."

X-FI Board model SB0460:
- original MC33078 opamp is MIC-IN configured in MONO mode and NOT a LINE-IN opamp, as shown in other parts of this thread.
- only half the opamp is used.
- inputs, In+2 and In-2, are shorted to ground. (to keep the second, unused opamp in quiescent state)
- output, Out2, is left open. (to insure opamp current demand is minimal)
- SB0460 Line-IN is capacitively coupled to the Wolfson WM8775 ADC, via C21 (J1 connector) and C22 (MIC-IN/Flexijack)

Picture:
http://www.esnips.com/doc/0b57366d-e.../X-FI-MOD-083b

REF:
MC33078 Datasheet: http://www.onsemi.com/pub/Collateral/MC33078-D.PDF
You rule Bichi. PM me with your addy and I will send you the cap

Whew
post #1382 of 2194
Just got my first SB series card after like 10 years of absence, I used to have a SB Pro a long long time back.


I have traced the wire that concern the primary two channels, it originates from DAC's pin 23, 24, 25, 26. Which is the differential output for the L and R channel. Since it is differential output into a op-amp with differential input, the net result of the DC on the original signal is canceled out. leaving only the signal in place.

People were right about those cap are not output caps for the opamp, those are actually the output caps for the DAC to OP. Which is really redundant. I have a AD1955 based DAC that uses similar circuit, and the DC bias automatically cancels out without the need for coupling capacitor.

Some might feel uneasy about it, as in times of failure, there's no cap to block DC.


But one gotta ask themselves, how often does that happen? If a reference design from a reputable DAC supplier is like that, I feel that there is no need for concern and just go for it. (Which I did)

I just took out some enamel wire, strip the coating and shorted all four caps of the primary channels.


But as usual, YMMV, Do it at your own risk.
post #1383 of 2194
Hey all,
So I read about this mod that seemed pretty easy... Well... (don't ask). I now find myself in need of a new SMT cap next to the opamp (I think it's a cap, it's beige as opposed to brown). It's this one:

Trouble is, I can't get a new one since don't know what the value is. I don't suppose anyone here knows what it is, do they?
post #1384 of 2194
Can anyone link me to some good caps to replace the 4 by the opamp? Preferably from mouser or newark and less than $10 for all 4.
post #1385 of 2194
Quote:
Originally Posted by Gautama View Post
Can anyone link me to some good caps to replace the 4 by the opamp? Preferably from mouser or newark and less than $10 for all 4.
you don't need a cap there, just short it out.

Creative's designer in their infinite wisdom decided to put coupling cap between DAC and OP amp when DAC is sending out differential signal. As an app note in National's audio product had said, a simple copper wire works better then caps, even those uber expensive teflon caps.

(Damn, it must be fun using company money to play with stuff like that....)

When you do short it out, do not remove the cap just yet. The cap will exert no effect on the signal once you have short it out, and the cap's leg also works as the "support" for your short copper wire. It takes about 5 minute including the warm up time of my soldering iron.
post #1386 of 2194
Quote:
Originally Posted by lutorm View Post
Hey all,
So I read about this mod that seemed pretty easy... Well... (don't ask). I now find myself in need of a new SMT cap next to the opamp (I think it's a cap, it's beige as opposed to brown). It's this one: xxx Trouble is, I can't get a new one since don't know what the value is. I don't suppose anyone here knows what it is, do they?
Lutorm,
- another lucky fekker-head...
- just happened to have the SB0460 out while repairing Germanium's blown SB0550.
- your missing cap measures 952pF and is connected to pin 3 (+INPUT) of the Line-Out opamp and signal ground, with opamp out of circuit.
- reads the same value for same capacitor, but on the "other" channel, pin 5 (+INPUT), Line-Out opamp.
- (see Cirrus Logic CS4382 Eval board datasheet, page 12, C67 and C63, link below)
- CS Eval datasheet specifies a 1500pF, C0G type capacitor and appears to be SMT size 0603.
- given unknown Creative design specs, Cirrus Eval datasheet, tolerance variences, and direct measurement results, my guess is:

1000pf (1nf), C0G (NPO) type, 0603 size, SMT, ML capacitor.

REF:
AVX PN: 06035A102KAT2A - DigiKey PN: 478-3718-1-ND
Digikey Catalog, page 1593: http://dkc3.digikey.com/PDF/T073/1583-1601.pdf

Cirrus Logic CS4382 Eval Board Datasheet:
http://www.cirrus.com/en/pubs/rdData...cs4382eb-2.pdf
post #1387 of 2194
Quote:
Originally Posted by bichi View Post
- your missing cap measures 952pF and is connected to pin 3 (+INPUT) of the Line-Out opamp and signal ground, with opamp out of circuit.
- reads the same value for same capacitor, but on the "other" channel, pin 5 (+INPUT), Line-Out opamp.
- (see Cirrus Logic CS4382 Eval board datasheet, page 12, C67 and C63, link below)
- CS Eval datasheet specifies a 1500pF, C0G type capacitor and appears to be SMT size 0603.
- given unknown Creative design specs, Cirrus Eval datasheet, tolerance variences, and direct measurement results, my guess is:

1000pf (1nf), C0G (NPO) type, 0603 size, SMT, ML capacitor.

REF:
AVX PN: 06035A102KAT2A - DigiKey PN: 478-3718-1-ND
Digikey Catalog, page 1593: http://dkc3.digikey.com/PDF/T073/1583-1601.pdf
Sweet, there is still hope! Thanks a bunch!
post #1388 of 2194
Quote:
Originally Posted by Maniac View Post
you don't need a cap there, just short it out.
When you do short it out, do not remove the cap just yet. The cap will exert no effect on the signal once you have short it out, and the cap's leg also works as the "support" for your short copper wire. It takes about 5 minute including the warm up time of my soldering iron.
Or you could use a silver conductive paint pen... takes about 10 seconds for all 4 caps :P
post #1389 of 2194
Quote:
Originally Posted by hardnrg View Post
Or you could use a silver conductive paint pen... takes about 10 seconds for all 4 caps :P
Aha~~ That's the spirit.

Kinda expensive tho, last I checked, it had been classified in my mind as the "Too expensive, too rarely used" type of tools

Still, good idea for those who don't want to use soldering iron.
post #1390 of 2194
Germanium, I put the 2 caps back, and these days I use a fan to blow the card directly, everything is okay, but when I disconnect the fan, the card disconnect itself. This lead me to think the self shutdown is really caused by the heat.

Only the regulator above the DSP is pretty warm,,, no other parts that warm,,,

Do you have advice how to get rid of this strange situation? the fan is noisy and it's just a workaround...
post #1391 of 2194
Quote:
Originally Posted by bichi View Post
Lutorm,
- another lucky fekker-head...
- just happened to have the SB0460 out while repairing Germanium's blown SB0550.
- your missing cap measures 952pF and is connected to pin 3 (+INPUT) of the Line-Out opamp and signal ground, with opamp out of circuit.
- reads the same value for same capacitor, but on the "other" channel, pin 5 (+INPUT), Line-Out opamp.
- (see Cirrus Logic CS4382 Eval board datasheet, page 12, C67 and C63, link below)
- CS Eval datasheet specifies a 1500pF, C0G type capacitor and appears to be SMT size 0603.
- given unknown Creative design specs, Cirrus Eval datasheet, tolerance variences, and direct measurement results, my guess is:

1000pf (1nf), C0G (NPO) type, 0603 size, SMT, ML capacitor.
I got my capacitor today, and was very happy to see that (after I finally managed to sold it in place) my card is now working again, with the 4562 in place! At this point I'm so happy that it would probably sound awesome even if I had put the old opamp in... The 0603 size is a little bigger than the stock components, at least on my card, but it's close enough that the pads fit, and it just made it a little easier to see to solder.

Just wanted to thank you again for measuring out that part and saving me $140 on a new card! I owe you man!

I picked up an XtremeGamer Fatal1ty in case this one was beyond saving, but it looks like I can return it now. Incidentally, my old XtremeMusic picks up absolutely zero EMI, nothing audible. The new "Fatal1ty" was awful, it hissed and hummed loudly with mouse motion, frame rate in games, etc. Kind of annoying to get a more expensive card and then have it perform so poorly... Much more happy with my old one! Is it just random between different cards, or are the Fatal1ty ones just worse than XtremeMusic across the board in picking up noise?
post #1392 of 2194
No. Sounds like you have a crappy card.
post #1393 of 2194
Quote:
Originally Posted by Twitchy_one View Post
Also, how do you short the other caps? I see it explained but I don't know how to do this. I'm pretty much completely new & without tools but I am interested in tinkering with it...

And for the ERS paper, does it have a sticky surface on one side, otherwise how does it stay on the card? Thanks, Twitchy
You can buy the ERS paper with or without the sticky back...the latter is more expensive. Like you, I am also wondering what precisely must be done to short the caps?
post #1394 of 2194
Quote:
Originally Posted by applevalleyjoe View Post
You can buy the ERS paper with or without the sticky back...the latter is more expensive. Like you, I am also wondering what precisely must be done to short the caps?
Does anyone have a high res pic of the back of the sound card? xtrememusic's back to be exact, if it have a clear image of the cap, I'll point out where to short it.

I must repeat that those bank of electrolytic caps are NOT power supply caps, or else something WILL blow up if you short it. If you are careful and have a strong light/good eyes, you can trace the wires going from the cap to the DAC chip. 2 cap per channel, 4 cap per OP.
post #1395 of 2194
Quote:
Originally Posted by Maniac View Post
Just got my first SB series card after like 10 years of absence, I used to have a SB Pro a long long time back.


I have traced the wire that concern the primary two channels, it originates from DAC's pin 23, 24, 25, 26. Which is the differential output for the L and R channel. Since it is differential output into a op-amp with differential input, the net result of the DC on the original signal is canceled out. leaving only the signal in place.

People were right about those cap are not output caps for the opamp, those are actually the output caps for the DAC to OP. Which is really redundant. I have a AD1955 based DAC that uses similar circuit, and the DC bias automatically cancels out without the need for coupling capacitor.

Some might feel uneasy about it, as in times of failure, there's no cap to block DC.


But one gotta ask themselves, how often does that happen? If a reference design from a reputable DAC supplier is like that, I feel that there is no need for concern and just go for it. (Which I did)

I just took out some enamel wire, strip the coating and shorted all four caps of the primary channels.


But as usual, YMMV, Do it at your own risk.
You are very correct. The only things negative I found by shorting the coupling caps is a slight & I mean slight increase in second harmonic distortion. All other harmonic distortion the same or reduced. There is a slight increase in noise below 1KHz on the elite pro card as well but you will not likely see that on the lower cards. What you will see though on the lower cards but not on the elite pro card is high D.C. offset. About 180mv or more as opposed to less than 5mv on the elite pro.
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