Thanks.
Any idea why the designer chose to put tantalums over aluminum electrolytics, is there any benefit of using the tantalum type?
Do you think that replacing the 4.7uf tantalums with higher capacity electrolytics would be okay?
Any idea why the designer chose to put tantalums over aluminum electrolytics, is there any benefit of using the tantalum type?
Do you think that replacing the 4.7uf tantalums with higher capacity electrolytics would be okay?
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I really can't answer that one I'm afraid. You have to assume the designer chose the best for the job and hopefully didn't chose them on the basis of them seeming more esoteric and so getting better reviews based on the visual quality of parts.
We just don't know.
As they are used for decoupling the rails you would only know by measuring and looking at the noise present and seeing if the tants gave a better or worse figure.
I can say with some certainty that replacing just one tant with an electro when it used as a rail decoupler in something like this will not materially effect things.
I would also stick to the same values if you replace them all. Bigger isn't better here and large increases can effect the way logic behaves when the rails first power up.
We just don't know.
As they are used for decoupling the rails you would only know by measuring and looking at the noise present and seeing if the tants gave a better or worse figure.
I can say with some certainty that replacing just one tant with an electro when it used as a rail decoupler in something like this will not materially effect things.
I would also stick to the same values if you replace them all. Bigger isn't better here and large increases can effect the way logic behaves when the rails first power up.
Thank you for your detailed answers, I appreciate your patience.
I’ll stick to the tantalums and replace them all.
As for the resistors surrounding the regulators, they measured the same as the parallel circuit of the left channel.
I’ll stick to the tantalums and replace them all.
As for the resistors surrounding the regulators, they measured the same as the parallel circuit of the left channel.
Make sure to buy recent drop type tantalum capacitors and also make sure to pay attention to the ESR. Ultra Low ESR types generally are not the best to use after regulator ICs. The old drop types are exactly the type that exploded.
Modern tantalum caps are fine but their reputation is severely damaged in the heads of DIYers because of the unreliability of tantalum decades ago. We always seem to trail behind as old info sticks. I use SMD tantalum capacitors a lot and never experienced a failure in normal use in the last 10 years. Unlike the older types the modern ones are also excellent in audio. They can also be used directly on rails unlike the older types.
The coltan debacle is something to think about though. Not a technical issue but an ethical one. I am not well informed about the current situation.
Modern tantalum caps are fine but their reputation is severely damaged in the heads of DIYers because of the unreliability of tantalum decades ago. We always seem to trail behind as old info sticks. I use SMD tantalum capacitors a lot and never experienced a failure in normal use in the last 10 years. Unlike the older types the modern ones are also excellent in audio. They can also be used directly on rails unlike the older types.
The coltan debacle is something to think about though. Not a technical issue but an ethical one. I am not well informed about the current situation.
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SMD tantalums don't suffer from the damaged coating at the leads that used to plague the drop type. Thirty years ago at Racal we used to use glass beads on the bead type leads to keep the coating safely away from the solder joint. This was an expensive manual step considered necessary for reliability
An update....
I replaced all the tantalums....good news it's alive and working (-:
After letting it play for a while I noticed that the AD1864 DAC chip became warm, the LM317, LM337 regulaters became really hot, the OP44s are hot but not "uncomfrtable" hot, I'm a bit worried about it, should I be worried?
Thanks
I replaced all the tantalums....good news it's alive and working (-:
After letting it play for a while I noticed that the AD1864 DAC chip became warm, the LM317, LM337 regulaters became really hot, the OP44s are hot but not "uncomfrtable" hot, I'm a bit worried about it, should I be worried?
Thanks
If it is all working correctly and you are sure all the caps are the correct way around then it's probably normal. Things like hot regulators are very common on a lot of commercial gear. If they actually sizzle water then they are to hot, if you can stand to touch them then they are OK.
VLSI (very large scale integration) chips can run very hot, there is a lot going on in there 🙂
As long as the supplies are correct and not higher than they should be then it will all be normal.
As long as the supplies are correct and not higher than they should be then it will all be normal.
If you have access to oscilloscope, see the power lines. Dead tantalum, warm regulator may have something to deal with diode failure.
As said, large scale integration chip contain lot of transistors, warm is not surprising.
As said, large scale integration chip contain lot of transistors, warm is not surprising.