As some of you may remember, I have been piecing together parts to build a project system for headphone listening. The idea is to recap the PSU, the Motherboard and the Sound Blaster 16 with low impedance, high ripple capacitors in an attempt to achieve better all-around sound.
Headphones being used: Sony MDR-V700
(note: This already sounds much better than running them off of the SbLive! in my main system! Any attempt at boosting bass on the SbLive! will distort heavily and there is no real power behind the music. Of course, the SbLive! is not supposed to utilize anything below 32-Ohms. With the SB16, the music is full and powerful. There are 6 notches above the bottom in WinXP volume control; I can turn Master and Wave up to only the first notch and it is as loud as I will ever want to listen. I am unclear on the impedance rating of headphones. If the onboard OpAmp looks at my 24-Ohm headphones as two 12-Ohm loads, then combined with the 9V regulated voltage supply, the power output should be nearly 1W or 1,000 milliwatts maximum. If it is seeing 24-Ohms on both sides than I believe the output should be between 200-300mW, IIRC.
--Progress--
Antec PP-303X:
Fully recapped with Samxon GC and GD line capacitors from BadCaps.net where possible. Anything too small capacitance-wise was replaced with Panasonic FM or FC line capacitors from Digi-Key. The large 200V mains were replaced with Panasonic TS-ED capacitors, also from Digi-Key. (Hey BigPope, I sure would like to try those 200V Samxon caps you were talking about.)
Abit BH6:
Has not been done, yet.
+Sound Blaster 16+ (CT2770):
For the sake of a refresh all necessary capacitors will be replaced with Panasonic FM or FC line capacitors.
1) C18, C132, C86 and C95 replaced. Digi-Key P# P11212. These are the four initial filter caps for the Voltage supply rails of the ISA bus. No obvious change.
2) C68, C79, C104 and C105 replaced. Digi-Key P# P11212. These four filter caps are tied to the rails of the two on-board voltage regulators. In my opinion, bass was improved.
3) C87 replaced. Digi-Key P# P12924. This is the Supply Voltage Rejection capacitor and reduces ripple. Some of the hiss in the background seems to have subsided and the music sounds overall smoother.
4) C89 and C99 replaced. Digi-Key P# P12923. These are the Feedback capacitors. (also referred to as Inverting Input DC Decoupling capacitors) I'm uncertain whether there was a change. The music sounds as if it may have a bit more power behind it. According to the datasheet, this capacitors can affect the low frequency cut-off. It calls for a 100uF capacitor, but Creative Labs used a 47uF capacitor. I may rectify this, later.
5) C83 and C? replaced. Digi-Key P# P12924. These are the Bootstrap capacitors. excerpt from datasheet: "The bootstrap connection allows to increase the output swing. The suggested value for the bootstrap capacitors (100uF) avoids a reduction of the output signal at low frequencies and low supply voltages." I cannot say whether I hear a difference or not, but this is still an important place to apply good quality capacitors. Logically, it would seem that this becomes more of a factor as you increase volume and more power is required. This would likely be a real issue if you were stressing the circuit.
6) C93 and C103 replaced. Digi-Key P# P12376. These are the Output DC Decoupling Capacitors. Their capacitance affects the low frequency cut-off. At 470uF, if I am running 12-Ohms the cut-off would be 28Hz. If I am running 24-Ohms the cut-off would be 14Hz. I did not change values, but very low-frequency performance HAS improved. Also, I noticed some details in the various areas of the frequency range in the tracks I have been listening to that I did not notice before. Again, they are much better caps than the originals and they are fresh. These capacitors are also important if you are using headphones as they block DC which would otherwise damage your headphones. Ideally, for best quality they should be non-polarized, but for the moment, I wanted to keep the capacitors the same diameter. (revised these comments after further listening) Maybe I should have done this first; maybe it would have allowed me to more easily noticed improvements from replacing other caps. doh!
7) C88 and C98 + C107 and C105 replaced. These are the Input DC Decoupling capacitors. The first pair seem to be tied to the second; what is going on here, I am not certain. Anyway, sound was overall more detailed and even the bass seemed clearer. (Edit: Actually, I have to admit that I had heard that my headphones are bass-heavy, but on the SbLive! that was absolutely NOT true. After replacing these signal caps, the bass does seem a bit heavy; enough to shroud some of the upper range that I used to notice, while the mid-range is beautiful. Applying film bypass caps to the filter caps of the ISA voltage rails did not seem to yield any real improvement as it did on the Live! I believe the 1uF signal caps on the SB16 really just need to be changed to films.)
That pretty much finishes up a basic refresh for use with hard-drive audio. There are many other traces, such as the Line-In and the several CD-A inputs which could be recapped, but I have no interest in these. Actually, I may refresh the Line-In for use with a Playstation 1 I am refreshing, mainly to be used as a simple CD-Player, but also to improve sound while gaming.
I do plan to replace many of the signal capacitors between the DSP and OpAmp as well as those between the Line-In jack and DSP with Metallized Polypropylene Films. I am still considering options for replacing the 470uF output capacitors as films would be too costly and bulky. Likely, non-polarized electrolytics bypassed with films will be the end result.
I am considering one or two very simple modifications for the card as well. For example: The original schematic for the TEA2025B uses a 100uF filter capacitor at the Voltage Supply pin. Creative Labs saw fit to simply place a 10uF electrolytic before and after the voltage regulator. I will try adding a 100uF later, swapping it from in front of to behind the regulator to see what happens. I am also going to recap the Sound Blaster 16 in steps to see how it affects the sound and post the results. I'll get pics up ASAP! Happy reading!
Headphones being used: Sony MDR-V700
(note: This already sounds much better than running them off of the SbLive! in my main system! Any attempt at boosting bass on the SbLive! will distort heavily and there is no real power behind the music. Of course, the SbLive! is not supposed to utilize anything below 32-Ohms. With the SB16, the music is full and powerful. There are 6 notches above the bottom in WinXP volume control; I can turn Master and Wave up to only the first notch and it is as loud as I will ever want to listen. I am unclear on the impedance rating of headphones. If the onboard OpAmp looks at my 24-Ohm headphones as two 12-Ohm loads, then combined with the 9V regulated voltage supply, the power output should be nearly 1W or 1,000 milliwatts maximum. If it is seeing 24-Ohms on both sides than I believe the output should be between 200-300mW, IIRC.
--Progress--
Antec PP-303X:
Fully recapped with Samxon GC and GD line capacitors from BadCaps.net where possible. Anything too small capacitance-wise was replaced with Panasonic FM or FC line capacitors from Digi-Key. The large 200V mains were replaced with Panasonic TS-ED capacitors, also from Digi-Key. (Hey BigPope, I sure would like to try those 200V Samxon caps you were talking about.)
Abit BH6:
Has not been done, yet.
+Sound Blaster 16+ (CT2770):
For the sake of a refresh all necessary capacitors will be replaced with Panasonic FM or FC line capacitors.
1) C18, C132, C86 and C95 replaced. Digi-Key P# P11212. These are the four initial filter caps for the Voltage supply rails of the ISA bus. No obvious change.
2) C68, C79, C104 and C105 replaced. Digi-Key P# P11212. These four filter caps are tied to the rails of the two on-board voltage regulators. In my opinion, bass was improved.
3) C87 replaced. Digi-Key P# P12924. This is the Supply Voltage Rejection capacitor and reduces ripple. Some of the hiss in the background seems to have subsided and the music sounds overall smoother.
4) C89 and C99 replaced. Digi-Key P# P12923. These are the Feedback capacitors. (also referred to as Inverting Input DC Decoupling capacitors) I'm uncertain whether there was a change. The music sounds as if it may have a bit more power behind it. According to the datasheet, this capacitors can affect the low frequency cut-off. It calls for a 100uF capacitor, but Creative Labs used a 47uF capacitor. I may rectify this, later.
5) C83 and C? replaced. Digi-Key P# P12924. These are the Bootstrap capacitors. excerpt from datasheet: "The bootstrap connection allows to increase the output swing. The suggested value for the bootstrap capacitors (100uF) avoids a reduction of the output signal at low frequencies and low supply voltages." I cannot say whether I hear a difference or not, but this is still an important place to apply good quality capacitors. Logically, it would seem that this becomes more of a factor as you increase volume and more power is required. This would likely be a real issue if you were stressing the circuit.
6) C93 and C103 replaced. Digi-Key P# P12376. These are the Output DC Decoupling Capacitors. Their capacitance affects the low frequency cut-off. At 470uF, if I am running 12-Ohms the cut-off would be 28Hz. If I am running 24-Ohms the cut-off would be 14Hz. I did not change values, but very low-frequency performance HAS improved. Also, I noticed some details in the various areas of the frequency range in the tracks I have been listening to that I did not notice before. Again, they are much better caps than the originals and they are fresh. These capacitors are also important if you are using headphones as they block DC which would otherwise damage your headphones. Ideally, for best quality they should be non-polarized, but for the moment, I wanted to keep the capacitors the same diameter. (revised these comments after further listening) Maybe I should have done this first; maybe it would have allowed me to more easily noticed improvements from replacing other caps. doh!
7) C88 and C98 + C107 and C105 replaced. These are the Input DC Decoupling capacitors. The first pair seem to be tied to the second; what is going on here, I am not certain. Anyway, sound was overall more detailed and even the bass seemed clearer. (Edit: Actually, I have to admit that I had heard that my headphones are bass-heavy, but on the SbLive! that was absolutely NOT true. After replacing these signal caps, the bass does seem a bit heavy; enough to shroud some of the upper range that I used to notice, while the mid-range is beautiful. Applying film bypass caps to the filter caps of the ISA voltage rails did not seem to yield any real improvement as it did on the Live! I believe the 1uF signal caps on the SB16 really just need to be changed to films.)
That pretty much finishes up a basic refresh for use with hard-drive audio. There are many other traces, such as the Line-In and the several CD-A inputs which could be recapped, but I have no interest in these. Actually, I may refresh the Line-In for use with a Playstation 1 I am refreshing, mainly to be used as a simple CD-Player, but also to improve sound while gaming.
I do plan to replace many of the signal capacitors between the DSP and OpAmp as well as those between the Line-In jack and DSP with Metallized Polypropylene Films. I am still considering options for replacing the 470uF output capacitors as films would be too costly and bulky. Likely, non-polarized electrolytics bypassed with films will be the end result.
I am considering one or two very simple modifications for the card as well. For example: The original schematic for the TEA2025B uses a 100uF filter capacitor at the Voltage Supply pin. Creative Labs saw fit to simply place a 10uF electrolytic before and after the voltage regulator. I will try adding a 100uF later, swapping it from in front of to behind the regulator to see what happens. I am also going to recap the Sound Blaster 16 in steps to see how it affects the sound and post the results. I'll get pics up ASAP! Happy reading!
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