Capacitor Questions (audio related)

[mtl777]

Hi, glad to find this forum!

My questions are not really motherboard-related, but they're about capacitor quality so I hope it's alright to post them here.

1. I have a Delta 1010 soundcard that has a proliferation of "En" marked caps (the "En" being inside an elipse). Sorry I have no picture, but the color is black with white negative stripe. Do you know who is the manufacturer of these caps? Are they good quality? How do they compare with Panasonic?

2. What caps would you recommend for power supply filtering/decoupling in a soundcard? I've heard lots of praises for Black Gate caps (Rubycon mfg) but they're too expensive. Are they worth the price? Alternatively, are the Panasonic FC's good enough? Or how about Panasonic FM? Are they better than the FC?

3. My soundcard uses electrolytics for coupling, which is not their ideal application. Why are electrolytics being used here? Is this because of cost considerations only? Can these be safely replaced with polypropylene caps? If so, what brands would you recommend?

4. I read that replacing a filter cap with two caps in parallel (each cap half the value of the original and the same voltage rating) will give you the same cap value and voltage rating but with the benefit of lower ESR and higher ripple current rating. Is there any downside to doing this, such as increasing the heat, or is the heat more or less going to be the same?

5. In general, how long is the shelf life of electrolytics? I have an old unused motherboard that's been in storage for 5 years whose capacitors I'm thinking of salvaging for an audio project. Not worth it?

Enough for now. I hope there are also audio enthusiasts here who are interested in these things. I would also appreciate if you could point me to a good forum where audio-related applications of capacitors are discussed.

Your help is greatly appreciated. Thanks in advance!

Michael

[willawake]

Re: Capacitor Questions (audio related)

http://forum.recordingreview.com/showthread.php?t=2261

[mtl777]

Re: Capacitor Questions (audio related)

Hey, great info in that thread. Thanks a lot!!

Michael

[starfury1]

Re: Capacitor Questions (audio related)

Suppose it depends on which side of the fence with black gates....
not that they wouldn't be (or rather want to be) good quality but probably way over priced

There was a post around here that said for Audio panasonic FC is the much preferred of the 2

yeah more caps less ESR (sort of like 2 resistors in parallel without getting into the complexity of ESR)
but dont think thats the issue with Audio, thinks its the HF frequency response or phase change that gets everybody going on what is or what isn't a good cap for audio...I think?...from memory

Me, my hearing FU's would probably sound OK
so not really the person to answer this one

Haven't had a look at will post link yet

Cheers

[999999999]

Re: Capacitor Questions (audio related)

Hi, glad to find this forum!

My questions are not really motherboard-related, but they're about capacitor quality so I hope it's alright to post them here.

1. I have a Delta 1010 soundcard that has a proliferation of "En" marked caps (the "En" being inside an elipse). Sorry I have no picture, but the color is black with white negative stripe. Do you know who is the manufacturer of these caps? Are they good quality? How do they compare with Panasonic?

The difference in performance is not likely to be very noticable on a sound card. Well there is an exception, on very old cards that had power amp chips on them then there was some improvement upgrading the bulk filter caps.

2. What caps would you recommend for power supply filtering/decoupling in a soundcard? I've heard lots of praises for Black Gate caps (Rubycon mfg) but they're too expensive. Are they worth the price? Alternatively, are the Panasonic FC's good enough? Or how about Panasonic FM? Are they better than the FC?

Sound cards tend to have suitable 'lytics and for the higher frequency some SMD caps near the active part they're meant to decouple, and sometimes a few more SMD sprinkled around the card. Unless the manufacturer was really stingy with a low budget, there is not so much reason to replace the power caps but if you wanted to do it anyway or suspect they were too stingy, use something like a general purpose low-ESR cap, it need not even be very low ESR but since they're commonly available you could use Panasonic FM or FC of a slightly higher uF value, something that still fits in the available space instead of being put on in a funny way.

3. My soundcard uses electrolytics for coupling, which is not their ideal application. Why are electrolytics being used here? Is this because of cost considerations only? Can these be safely replaced with polypropylene caps? If so, what brands would you recommend?

It's for cost reduction but also the size factor, that typically the coupling caps need to be around 4.7-10uF and a decent film cap in this value is quite large, prohibitively so in the space available on most sound cards. Yes it would be safe to replace with polypropylene in the same uF value, if they'll fit. No particular brand will matter, choose based on the dimensions most accomodating to where you'd put them - industrial types are fine, they need not be something considered botique. Since the audio output voltage is quite low, choosing the lowest cap voltage rating you can find will result in a smaller cap size.

Replacing these coupling caps is the largest improvement to be made to the card, the power decoupling is pretty trivial compared to this. However, if you aren't directly powering headphones and have an amp stage of some sort after the card and that amp has input coupling caps, you don't necessarily need to have the output coupling caps on the sound card at all, they can be shorted out. The danger in this is if you forgot you had done it, gave the card to someone else or someone else plugged headphones in while it was like this, it could damage the headphones and the card.

4. I read that replacing a filter cap with two caps in parallel (each cap half the value of the original and the same voltage rating) will give you the same cap value and voltage rating but with the benefit of lower ESR and higher ripple current rating. Is there any downside to doing this, such as increasing the heat, or is the heat more or less going to be the same?

As important a question is whether there is any upside to doing it. Soundcards are digital chips plus analog with feedback loops, you don't need an idealistic cap filtering scheme to achieve results indistinguishable from stock on any decently designed card. There are no large current changes that would suggest trying to parallel caps and to parallel them with only one space for it, you may end up with longer cap leads. The downside is that it looks ghetto but closely positioned parallel caps aren't likely to cause any resonance so there is no inherant problem from a circuit functionality standpoint, and there was never any heat issue in the first place, and none if you did it. If you really wanted to super-tweak the card just for the sake of doing it, you would put large value film caps in these 'lytics positions. I wrote "film" instead of polypropylene because there isn't enough difference in this purpose to be picky about the type, a smaller (per same uF) mylar 10uF could substitute for a similar value 'lytic, but not a much larger value 'lytic.

5. In general, how long is the shelf life of electrolytics? I have an old unused motherboard that's been in storage for 5 years whose capacitors I'm thinking of salvaging for an audio project. Not worth it?

That's not just shelf life, they have been used too. Regardless, a manufacturer rates until the cap falls a certain % below it's spec sheet parameters, but that doesn't necessarily mean the cap has fallen below properties that would exclude it from being acceptible for a sound card. It just isn't a demanding role on a sound card. The caps should be fine on an sound card unless they were quite worn out from use on the motherboard or many years old and dried out. With a decent stable electrolyte, that's well over 10 years.

However, after sitting with no charge for an extended period of time, they will reform some and after several hours of use will perform better. On a power amp this might be noticable, but on a sound card it is less likely.

[starfury1]

Re: Capacitor Questions (audio related)

Thanks 9's...as always an in depth and well put together reply
(unlike my disjointed waffle)


humm now
"Haven't had a look at will post link yet"..... that sort of didn't read right

It should have read;

"I Haven't had a look at the link posted by willawake yet"