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Hotrodding the X-Fi: A Layman's Guide (No 56k) - Page 121

post #1801 of 2194
He must got the wires wrong or got a broken vire, because you can't map the Front Right to -> Rear Right. This is impossible to do with simple opamp change. Front Right and Left is done with the first opamp on the top, while the Rear Right is done in the middle opamp from the there ones in line...
So this is not possible. He swaped the wires and one wire is broken lose. At least I think it is like that...

Regardless, I have a question. Some smart recommendations for hi-quality the mic input M33078 opamp replacement? (if this is even a opamp, but I think it is...)
post #1802 of 2194
Quote:
Originally Posted by trodas View Post
Regardless, I have a question. Some smart recommendations for hi-quality the mic input M33078 opamp replacement? (if this is even a opamp, but I think it is...)
it is a standard-pinout dual opamp.
post #1803 of 2194
Quote:
Originally Posted by trodas View Post
He must got the wires wrong or got a broken vire, because you can't map the Front Right to -> Rear Right. This is impossible to do with simple opamp change. Front Right and Left is done with the first opamp on the top, while the Rear Right is done in the middle opamp from the there ones in line...
So this is not possible. He swaped the wires and one wire is broken lose. At least I think it is like that...

Regardless, I have a question. Some smart recommendations for hi-quality the mic input M33078 opamp replacement? (if this is even a opamp, but I think it is...)
I've triple checked all the connections with a multimeter and all the wires are connected to the right place. I have an X-Fi board as well so I used that one as a reference for where the wires should go.

The only thing I can think of is the fact that I am using extremely thin wires, would interference cause a problem like that?
post #1804 of 2194
Random Murderer -
Quote:
Some smart recommendations for hi-quality the mic input M33078 opamp replacement? (if this is even a opamp, but I think it is...)

it is a standard-pinout dual opamp.
You sure? And witch one? Searching for M33078 returned only results like:
http://www.alldatasheet.com/datashee.../ADM3307E.html
ADM3307E - 15 kV ESD Protected, 2.7 V to 3.6 V Serial Port Transceivers with Green Idle

...witch is certainly not the chip we see above.


NoKKiE - no, no amount of interference could change your Front Right to -> Rear Right. You must connected the jacks wrongly. And use less thin wires anyway
post #1805 of 2194
Quote:
Originally Posted by trodas View Post
Random Murderer -

You sure? And witch one? Searching for M33078 returned only results like:
http://www.alldatasheet.com/datashee.../ADM3307E.html
ADM3307E - 15 kV ESD Protected, 2.7 V to 3.6 V Serial Port Transceivers with Green Idle

...witch is certainly not the chip we see above.


NoKKiE - no, no amount of interference could change your Front Right to -> Rear Right. You must connected the jacks wrongly. And use less thin wires anyway
yea, i'm damn sure.
post #1806 of 2194
Quote:
Originally Posted by NoKKiE View Post
I've triple checked all the connections with a multimeter and all the wires are connected to the right place. I have an X-Fi board as well so I used that one as a reference for where the wires should go.

The only thing I can think of is the fact that I am using extremely thin wires, would interference cause a problem like that?
I seem to have fixed it and everything runs fine now. I cleaned up some solder that was connecting the 12V connection to the connection right next to it (not on the op amp, the other thing). I used my multimeter and it seemed they linked together anyways so I didn't bother cleaning it up earlier. I did it just out of completeness and all the problems went away... heh. Thanks for all the help guys!
post #1807 of 2194
Quote:
Originally Posted by NoKKiE View Post
I seem to have fixed it and everything runs fine now. I cleaned up some solder that was connecting the 12V connection to the connection right next to it (not on the op amp, the other thing). I used my multimeter and it seemed they linked together anyways so I didn't bother cleaning it up earlier. I did it just out of completeness and all the problems went away... heh. Thanks for all the help guys!
Yup, thanks for all the help! Too bad I thought it was hopeless and went ahead and ordered a Xonar D2 anyways. =(
post #1808 of 2194
I'm glad you figured it out!

I'm not faulting you, but one of the first steps in troubleshooting something like this should have been to reflow all the solder joints. At least that's what I do. I flood the area in flux and just make each leg look shiny. Then it just takes some alcohol and a little time with the brush to make everything pretty
post #1809 of 2194
Just wondering whether I can upgrade the I/O bay of X-Fi platinum. The bay has two boards, of which the top one is for digital out, the bottom one includes the headphone out and line-in. So I show the bottom board here. When I look the board, I can immediately think of replacing the JRC 4556A with a better OPAMP, such as LM4562, or any better one if you could suggest. However, I can’t guess which capacitors needed to change for coupling and power filtering. Could you please take a look at it? I attached the pictures. Thank you.

I am also wonder it is a good idea to mod the I/O bay, since there is a long data bus from sound card to the bay’s board. There is big path for the EMI enter the data bus. Will it create a lot of noise? I am interested in mod the I/O bay because I would like to use it for headphone amplifier for good quality music, while listen the regular sound with the speakers from the line out of the sound card.
LL
LL
post #1810 of 2194
Of course there IS a much better one that picky LM4562 - AD8599!

Just check there for the results: http://www.head-fi.org/forums/f6/x-f...91/index5.html

Add shielding to the cables and to the bay too, use the TI shield material, I seen it in Percy's Audio site for reasonable price. Shield both EMI and RFI well.
post #1811 of 2194
How much is the DC supply on board to the 4556A and 4558C on X-Fi platinum? if it is only +-5V, maybe it is not enough for AD8599, which requires +-9~36V
post #1812 of 2194
Have a bit of faith, will ya?

We tested that already and X-Fi Fatal1ty supply only +/- 5V to them. I using them NOW and I'm more that happy.

Regardless, the +/- 5V might sound as "not meeting the specs", but if you read the datasheet you actually notice that this is 10V - both these voltages have to be added into the calculation, so we are at 10V and we are fine, well within the specs. Near lower range, true. But you can always and easily tweak up the 7805 / 7905 output voltages. You sure know that. It is just a matter of two resistors...

Analog Devices: AD8599: Dual, Ultralow Distortion, Ultralow Noise Op Amp :: Operational Amplifiers (Op Amps) :: Amplifiers and Comparators
post #1813 of 2194
Trodas:

what is 7805/7905? Can I increase the bias by tuning some resistors?

I want to comfirm the bias to a OPAMP.
For example, for the AD8599, +5 to V+ and -5 toV- is the same as 10V to V+ and ground to V-?

thank you.
post #1814 of 2194
The 7805 / 7905 is well-known fixed voltage regulators. (sidenote - if you don't know what 7805 is, then you should not even consider moding the card, you are messing with things w/o knowing what they are, that could end up pretty bad...) However their output voltage can be easily adjusted by just a simple two resistors voltage divider, increasing the voltage on the chip "common ground" and since it trying to stabilize the voltage to the fixed amount between output and common ground, then you can easily regulate/modify the output voltage...
Just check the datasheed for many and many and many examples how to use these fantastic chips: http://www.st.com/stonline/products/...143/l7812c.pdf

Bias to opamp? I would say opamp operating voltage...
And yes and no.
Yes for the calculation of the minimal operating voltage, but you have that mentioned already in the pdf datasheet I linked there. Please read materials first, before asking.
No for the results. Powering opamp from +/- voltage yield better results, especially in higher frequency of the audio spectrum.

And since these opamps are in the pre-amp stage, then there anything has a HUGE impact on the results.

Hope that helps.


PS: Digi-key stated the obvious quite clearly too:
http://search.digikey.com/scripts/Dk...AD8599&x=0&y=0
You see? Single voltage - 9 V ~ 36 V, required. But - double voltage supply: ±4.5 V ~ 18 V
I hope all is clear now.

PS2. I somewhere suggested that the input opamp (MC33078) should be replaced too. Good choice seems to be again the AD8599 - but hold your horses! This time the opamp is powered from +5V only (the leg 8), leg 4 is NOT connected to the -5V as all other opamps there - but to ground. Hence this one is getting only 5V. AD8599 require by specs at least 9V. I'm affraid that it will not work good there... time to find another opamp, +5V capable one
post #1815 of 2194
I was hotrodding my X-Fi and got a blob of solder on the 3rd. resistor (counting top down, to the left of the main OPAMP)
Its value, I assume, is the same as the other three, 33ohms.
The problem is that I totally wacked the solder pads and can't find where to connect a replacement resistor.
Does anyone know where the ends of that resistor go to so that I can solder in a standard 33ohm 1% resistor?
THANKS for any help!!
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