After having a chance to listen to my new SB550 in both stock & modded form I definately like it better modded in spite of slightly worse specs, nothing durastic mind you spec wise, but again the sound is what really counts after all. We don't listen to test gear, we listen with our ears so that the goal is to get better sound according to the ears.I use the tests only to verify nothing durastic is wrong.

On my headphones the boominess has almost totally disappeared replaced with wonderfully tight deep bass that extends very deep. Midrange has more life to it as does the treble without being harsh. This is in spite of the specs showing there only improving the very deep bass. Frequence response is within +.01/-.04 on 96KHz sample rate & +.01/-.03 on 48KHz sample rate.It was +01/-.09 stock on both sample rates before. By the way these Denon AH-D1001 are excellent phones for the money. They definately will reward you if you feed them right with good source & amp

Note I shorted the 1st line in coupling caps to get these & do not plan on using the microphone on the flexijack, otherwise the specs would have been +.01/-.07 modded.

1. Germanium, after my mods, the card often disconnect the power itself to do some protection I think, and the card will not work, even no that hardware detected in BIOS. Then after ~3 hours, it will restore to normal. Maybe there are some negative feedback from my larger caps throughout the board caused the self protection.
Do you know why the exact root cause & how to get rid of it?

2. Now I disconnected the external power supply cable, so the breakout box is no use. I did the RMAA, the spec is a little bit better and spikes in noise are mitigated.
Do you think it's better to disconnect the cable? Someone thinks it will give the card more power to let it sound more dynamic through it's 5v DV in.

Thanks!!

Quote:



I have not had that problem myself. look for a short somewhere as that will cause the circuit breaker on the card to open for a time. Poor solder joint. Solder bridge & the like. If you were heating the leads of the metalyzed film caps to long there may be a leakage problem with current going through them when it shouldn't. Remove the caps you put in there & put a volt ohm meter across them on the ohm setting & see if the measure anything other than infinate impedance.

On my setup I needed to mute all inputs in order eliminate other sources of noise. My breakout box is still connected & powered for my tests showing clean noise floor.

Talked to David and he said the LDII++ is AC coupled not DC, so I assume it would be best to replace the caps. Whats a good clean cheap cap to do it with?

Quote:



Thanks,
I do recommend connecting the external power cable, it brings more dynamics, but if the psu is poor, more noise will come in.

Quote:



Glad its working now.

Were the diodes shorted accidently & you removed the short now?

Hows the actuall sound now that its fully funtional?

Quote:



I relinquish that, since the self-protection occurred again after I shorted the 2 diodes. So don't short the diodes!! I just removed the bridges.

I tried other methods, all failed. So I'm thinking that it may be the internal feature of the card BIOS or even DSP. I don't know...

passively,
I suspect it is caused by my replacement of the 2 opamp caps with 2 50v 1000uf caps, I just detached the 2 caps to see if the self-protection again.

Quote:



I would be more inclined to look at the powersupply mods for the DSP unit as a possable cause as these circuits can be finicky.

Quote:



can you please take a look at the powersupply circuit around the board? I don't know how to enlarge the overcurrent protection threshold. I don't have much circuit knowlege and this issue caused me much annoyment although the music from the modded card is truely amazing!!

Quote:



If you modded the power section by the DSP try returning it to stock. You are unlikely to have any gains there in real sound quality & may if done wrong end up with more noise & possably what you are experiencing now. There may be some bad resonanances causing increased power drain. Never increase the power threshold of the circuit breaker as that could lead to far more dangerous consequences such as fire. Find the cause of the overcurrent & fix that.

The DSP is a very power hungry device & needs lots of clean power. I believe the circuit breaker is there primarily to protect that section as that is the only section that really draws a lot of power. The only other possabilty is the breakout box as you said it didn't protect itself at least in your first post regarding this issue, when it was disconnected but that doesn't explain the fact that the whole soundcard shuts down. If the circuit breaker was for the breakout box power only the breakout box would be effected not the whole card. this leads me back to the DSP power supply. Without a schematic I would be at a loss to trace it. Hopefully bichi has a solution. The breakout box really draws very little power if running correctly & unlikely to trip the circuit breaker as it seems to be pretty heavy unit already. The breakout box does add a small power increase on the DSP & if the DSP is already near its limits due to bad power resonance that could trip the circuit breaker.

Does the DSP get unusually hot? That could be a clue. You could also try directing more air over the card & seee if that helps.

Quote:




Thanks, since the card is not shutdown during computer startup, I would also think it's the heat that triggered the issue. I changed all the 7 opamps to LME49860, maybe caused more current drain & that triggered the overheat of some IC, then the IC do self-protection.

1. My DSP is not heat, but the 3 leg power regulator above the memory chip very hot & the hotest IC on board, do your card behave the same?


2. Also, can I remove the 2 additional opamps directly & these 2 seem for DELL-specific extension.

3. I changed the 4 caps for ADC to 4 6.3v1000uf ones. The datasheet says only 2 are needed for + and - (1000uf is better for low response each), why there are 4 on board? Do you think the 2 6.3v470u in parallel to make near 1000uf for each + or - due to space limitation (don't have room for 6.3v1000uf ones)?

4. I'm now disconnecting the 2 opamp caps (modded to 2 50v1000uf from 220uf), no such shutdown so far, but the sound is terrible!! no deep bass, if large bass in original soundtrack, I can hear the sound become small due to insufficient current/voltage & the highs not bright!! very terrible, and I want to find the root cause and remedy for the shutdown asap... try to get rid of no use opamps and caps to reduce overall current is a way, I need your help...

Quote:



1. yes it gets pretty warm. After being on for some time the DSP chip got pretty close to the same temp as the regulators but takes much longer to get there.

2. Not Dell specific, I have the same opamps. They split the signal into a differential signal to feed the ADC.

3. I do believe these to be required and are shown in the data sheets I have seen. These supply the +&- voltage reference for the ADC & there are 2 per channel. Each has a different voltage. 1.2 volts & 3.6 volts. There is also a small ceramic cap that goes between the 1.2 &3.6 volt ref..

4. Stands to reason that the electrolytics are needed there. They should have had no bearing on the hot voltage regulators though as these are not fed by those regulators. They are fed directly from the motherboard + & - 12 volt rails. The regulaters feed the ADC & DAC +5 volt rail & probably the breakout boxes ADCs & DACs. All the opamps on main board fed +&-12 volts. I realize that I mentioned the possability of removing the 2 electrolytics with large value metalyzed films there but in light of you findings I will rethink that option. I have not actually removed them myself to test that theory. It was only a thought I had is all. further more when I tried the 2-12uf metalyzed film caps on the new card they added too much noise but the 2-3.3uf caps worked fine. I guess the shorter leads do help but may be that some cards are more sensitive than others even of the same model.


One thing you could try doing is getting more air flow over the soundcard. The soundcard sits in proably the worst spot in the PC for airflow. If you have an open spot below the card try removing the cover to that open spot to let more air by the sound card. Also if you have heat producing cards in the next spot down try moving it to a spot further down or above if there is room. If not install a small low speed fan pointed toward the soundcard. By all means though put the 2 electrolytics back in & make sure they are in the correct polarity.

Hello folks!

I have done several X-Fi mods and never had a problem untill now. I did one for a friend and was having problems with it and I noticed that one of the solder pads was damaged.

This is the one that is damaged...



I have good soldering skills but my diagnostic skills are lacking. If anyone would be willing to help find where it leads to, there is 16v 1000uf Blackgate cap in it for you.

Thanks in advance guys

Quote:



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 C48 and C49, Line-IN/MIC-IN/Flexijack with no opamp in path.

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

REF:
MC33078 Datasheet: http://www.onsemi.com/pub/Collateral/MC33078-D.PDF

Dibs on the cap if not needed >.<