Modified SoundBlaster Digital Music LX

Japanese/English

Japanese version here.

listmarkintroduction





When I bought a NotebookPC, I used the soundcard of onboard and its headphone jack is placed the front of PC, so the RCA cable disturbed me.
I wanted a USB soundcard.
Then I found a inexpensive soundcard, SoundBlaster Digital Music LX, and bought it.
It was about &50.
I wasn't going to use it for a long time, but it was good against my expectation.
So I've used it for a longer time than I expected.

But I made amp and speaker, some things I wasn't satisfied appeared.
My desire is bottomless.

Then I decided to improve SoundBlaster Digital Music LX.




listmarkdismantling


I found a rubber which were aout to come off, so I dared to remove it.



Then a screw head appeared.
I couldn't suppress my instinct to open it, I turned it.



Then it opened.



Now I lost the guarantee of it completely.





The concentration is surprising.
A huge number of OpAmps, chip resistances and capacitors are on it.

The patterns wchich are next to optical output and headphone jack are vacant.
I guess that LX uses the same board as PX does.




listmarkimproving USB bus power


SoundBlaster Digital Music LX adopts USB bus power.
PC emits a lot of noises.
LX recieves power from PC, so the power will have many noises.
In short, USB bus power is not suitable for audio.

Then I improve it by inserting a decoupling capacitor between power supply and GND.
Decoupling capacitor will work for smoothing power supply.



Following the patterns, It may be good if I insert the capacitor into the IC with red mark.

If you see the same direction of upper and following figures, please connect 100-470uF capacitor like following.





I wired actually.





I couldn't find audio-grade capacitor in electorical parts shop near my house, so I bought a Tantalum capacitor unwillingly.



It looks cute.
Its color is good.
It is 220uF and endures 6V.
At upper picture, the left leg is plus.
It was very expensive, I bought it for about $3.


2008/11/17 added
It is dangerous to select a tantalum capacitor for the use of decoupling because it causes short circuit when breaking down.



It looks funny because the blue stands out.




the result of this

The bass sound got to be powerful and its volume increased as a whole.
I used bass booster before, but I didn't need it any more.


I also checked by using the software, RightMark Audio Analyzer.

before after
Frequency response (from 40 Hz to 15 kHz), dB: +0.00, -0.00 Excellent +0.00, -0.00 Excellent
Noise level, dB (A): -400.0 Excellent -98.2 Excellent
Dynamic range, dB (A): 91.0 Very good 98.1 Excellent
THD, %: 0.0044 Very good 0.0003 Excellent
IMD + Noise, %: 0.0075 Excellent 0.0037 Excellent
Stereo crosstalk, dB: -364.0 Excellent -99.3 Excellent
IMD at 10 kHz, %: 0.0088 Very good 0.0040 Excellent


It is excellent!

Noise level and Dynamic range were vastly improved.
But Noise level and Stereo crosstalk were failed to measure before improving.

For further comparison, please refer to here.


I wonder why Creative hasn't inserted the capacitor.




listmarkchanging all capacitors into audio-grade capacitors


The capacitors on LX board counted thirty, they were all Jamicon made in Taiwan.
I thought they were easyly to be taken off, so I tried to exchange to audio-gradee capacitors.


220uF JAMICON 16V 524MO(M) SK 85 degrees Celsius * 2
47uF JAMICON 16V 524MO(M) SS 85 degrees Celsius * 1
22uF JAMICON 16V 524MO(M) SS 85 degrees Celsius * 8
10uF JAMICON 16V 524MO(M) SS 85 degrees Celsius * 18
4.7uF JAMICON 16V 524MO(M) SS 85 degrees Celsius * 1
1uF JAMICON 16V 524MO(M) SS 85 degrees Celsius * 1

into

220uF OS-CON 10V 10SA220M * 2 231 yen
47uF Nichicon MUSE ES 16V UES1C470MPM * 1 47 yen
22uF Nichicon MUSE ES 16V UES1C220MEM * 8 47 yen
10uF Nichicon MUSE ES 16V UES1C100MDM * 18 42 yen
4.7uF Nichicon MUSE ES 25V UES1E4R7MDM * 1 42 yen
1uF OS-CON 30V 3OSC1M * 1 84 yen


These were the changes.




OS-CON
This is the best for using decoupling capacitor.
If we use it, the sound will be more tight and clear.
This is a electrolytic capacitor, but it works excellent as if it was film capacitor.





These are MUSE by nichicon.
MUSE is high-grade capacitor which is used in expensive amp.
I used non-polar capacitor, MUSE ES.



It was difficult exchanging capacitors against my expectation.
The holes of print board were small and solders were hard to melt.
JAMICON took root in board like they were devil.


But I got the knack of it, after heating the soldering iron (it should be about 60W) untill it got piping hot I melted solders at a stretch and removed JAMICON.
Then I heated the leg of new capacitor and melted solders by the leg.





The board was grown over with weeds.
Be careful about not to hurt the board by heat.
MUSE and OS-CON were bigger than JAMICON, so I put them slanted.





It looks funny.





after exchanging

The bass sound got to be more powerful and thick.
I felt something broad-minded in it.

I checkt new LX by RMAA, but there was no change.


My soundcard was reborn.
Now it is some high-grade device.


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