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Hotrodding the X-Fi: A Layman's Guide (No 56k) - Page 118

post #1756 of 2194
Quote:
Originally Posted by Apocalypsee View Post
Hmm, that makes we wonder, what are the reason those transistor is there in the first place if it can be controlled by software?
think of it as a valve(not an electron tube, but an actual water valve) that remains open because the audio chip sends it a signal to stay open and let audio through. when that signal is not being sent(like when shutting down your computer) the valve closes and halts the flow of water(audio). it's just an automatic noise reducer, but unfortunately it can also affect audio signal...
post #1757 of 2194
Quote:
Originally Posted by Random Murderer View Post
think of it as a valve(not an electron tube, but an actual water valve) that remains open because the audio chip sends it a signal to stay open and let audio through. when that signal is not being sent(like when shutting down your computer) the valve closes and halts the flow of water(audio). it's just an automatic noise reducer, but unfortunately it can also affect audio signal...
I think that one only function when the computer unload the driver(such as restart PC), am i rite? if we press mute on the volume button, this component will function or not?
post #1758 of 2194
Quote:
Originally Posted by Random Murderer View Post
think of it as a valve(not an electron tube, but an actual water valve) that remains open because the audio chip sends it a signal to stay open and let audio through. when that signal is not being sent(like when shutting down your computer) the valve closes and halts the flow of water(audio). it's just an automatic noise reducer, but unfortunately it can also affect audio signal...
I see, that makes perfect sense, actual valve introduces turbulent, energy loss etc I guess that is the same as in circuits (I learn fluid mechanics)

Quote:
Originally Posted by coolkwc View Post
I think that one only function when the computer unload the driver(such as restart PC), am i rite? if we press mute on the volume button, this component will function or not?
This transistor can't be controlled by software, it just sense whether ther is a signal or not, if the signal is there it will open if it not it will block any small signal from going through. I'm guessing though, judging from what Random Murderer said
post #1759 of 2194
This is the Sound Blaster Digital Music SX, being touted as "audiophile quality" by creative.





So it looks like it uses the CS4398 as DAC chip which is good stuff? Or is it CS5351 that is also found on the board?

There is a if I were to mod it, is it the 4556 at the bottom of the second picture that I replace with the LM4562? Where are the capacitor in my case?

It sounds pretty decent to me though.
post #1760 of 2194
apatN - you should NOT use audio capacitor in voltage filtering application. This mod was proven to be pure nonsense (laughable on top of that, but so are many my mistakes as well, so...) long time ago. Use Panny FM 1000uF 6.3V, Samxon GC 1000uF 6.3V as I did there: X-Fi sound bugs? I think I have a solution. - Head-Fi: Covering Headphones, Earphones and Portable Audio
or any decent low ESR capacitor. Do not use super-low-esr ones (polymers), or you head to another problem...


coolkwc -
Quote:
bypassed those component and claim the sound more clear now...
No wonder. Anything staying in audio path is distorting the signal.


catx -
Quote:
Bypassing them will greatly improve the sound, but you will ear pops/cracks when shutting your pc off or changing audio mode.
How loud are these? I did not change audio mode at all, lol, but if they are managable, well... the audio quality is worth them, right?
How about to use AD8599 as opamp? The LM4562 is ofter regarded as "total sonic crap" ...
And how about to short the unnecessary caps between DAC and opamps? Helped a lot in my case

Quote:
Here is a pic of my card after the bypass
Very nice! Now what about the other 4 channels? This is just the L/R channels, what to do to bypass the others? RL/RR, CENTER, SW...?

Quote:
would be interesting to find out the specs of the original transistors and check if better parts (higher bandwidth?) can improve the sound without eliminating the muting circuit
Impossible. Anything in the audio path will introduce problems. These transistors hardly need more bandwith - they can go to Mhz at least - and they are opened all the time. The problem is, that they are simply not good for the audio at all...


Navyblue - I see 4 pcs of the 4556 opamps there And the sound quality you hear depends, well, on the amplifier and repros you are using - as well as the audiosource too... So it is not so easy to say that it "sounds well" ...
post #1761 of 2194
nevermind...
post #1762 of 2194
Quote:
Originally Posted by trodas View Post
Navyblue - I see 4 pcs of the 4556 opamps there
Where are they? Btw those two pictures are the same board from opposite angles.

Quote:
Originally Posted by trodas View Post
apatNAnd the sound quality you hear depends, well, on the amplifier and repros you are using - as well as the audiosource too... So it is not so easy to say that it "sounds well" ...
Sorry I don't get you, what I meant by it sounded decent I mean it is decent as a source, compared to other sources like CDP. How does it have anything to do with all those you mentioned?
post #1763 of 2194
Quote:
Originally Posted by Navyblue View Post
Where are they? Btw those two pictures are the same board from opposite angles.
there may be four, but i only see three. the one you mentioned and then two right near one of the pots towards the front(back?). i also see two TI chips, but i don't know what they are since i can't read the part numbers...
post #1764 of 2194
Yes, there are many of them, but I only see one that has 4556 on it.

There are 2 line in, 2 line out (not sure if they are in fact linked), 1 mic and 1 headphone out. I guess there will be one chip for each of these?
post #1765 of 2194
Quote:
Originally Posted by Navyblue View Post
Yes, there are many of them, but I only see one that has 4556 on it.

There are 2 line in, 2 line out (not sure if they are in fact linked), 1 mic and 1 headphone out. I guess there will be one chip for each of these?
i was saying that i see 3 4556's in addition to two ti chips.
post #1766 of 2194
Quote:
Originally Posted by Random Murderer View Post
i was saying that i see 3 4556's in addition to two ti chips.
Yes, but where? At least tell me which quadrant to look at.
post #1767 of 2194
Quote:
Originally Posted by Navyblue View Post
Yes, but where? At least tell me which quadrant to look at.
post #1768 of 2194
Thanks a lot.

But those two at the right are ST's 4558C and not JRC's 4556A.

So, which of these do I touch?
post #1769 of 2194
Quote:
Originally Posted by Navyblue View Post
Thanks a lot.

But those two at the right are ST's 4558C and not JRC's 4556A.

So, which of these do I touch?
i don't know. your best bet is to wait for trodas or cotdt or someone of the like to answer
post #1770 of 2194
Nah, we can't respond, since we did not ahve that card... So, first measure witch one is witch and ...

Is not this a thread about X-Fi mods?
What about figuring out there a X-Fi scheme? For example the scheme AFTER these opamps...
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