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Old 15th February 2007, 11:46 PM   #1
ROBSCIX is offline ROBSCIX  Canada
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Default Questions about Caps on outs or Ins?

Hey guys, I am new to the DIY audio game but I like it alot and I ma learning at a constant rate. The circuit I am working with is a analog output stage on a newer soundcard. A few people have bypassed the DC blocking caps on the analog outputs. They told me that for this particular circuit the DC offset is not really a issue and the increase in sound quality from bypassing is worth it. My question is would using better caps such as black Gates help reduce the negative effects of Capacitors on the signal outputs? If I am using incorrect terminolgy feel free to correct me, I am in the learning phase. I noticed on headphone amps the are similar to the input caps. I guess output caps on one device are the same as input caps on another the perform the same function.

So feel free to educate me on this subject

Thx for the help guys.
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Old 15th February 2007, 11:59 PM   #2
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Yes generally you can improve the caps in circuits but be aware that it is a bit of a contentious topic. If it is a relatively high value cap ie over 10uF then Blackgates are good if you can get them as I heard they were in short supply. And if a large value electrolytic it would pay to see if it was "polarised"or not. (See standard introductions on caps) For smaller values the consensus over the last 30 yrs has been; polypropelyene (I can't spell....sorry), polystyrene, and polycarbonate with people feeling fairly stronly opposed to tantalum and mylar/polyester. There is some scientific evidence for these views when considering dilectic absorption and one or two other factors. The Walt Jung/Marsh article on capictors is rewarding in this area and pretty acessible on the web. Good luck and enjoy...etc
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Old 16th February 2007, 12:39 AM   #3
ROBSCIX is offline ROBSCIX  Canada
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What is your opinion on just byassing them if the DC offset is negligble? Two people I have spoke with have done just that. The sound quality has of course gotten better becasue as I read it Caps in this position although possibly needed are bad for the overall quality of the sound.
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Old 16th February 2007, 06:29 AM   #4
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Usually no probs as the input circuitry of the next piece of equipment will usually have a cap. But test to see whats coming out and be aware of any warranty conditions that may be violated due to the modification.
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Old 16th February 2007, 01:02 PM   #5
ROBSCIX is offline ROBSCIX  Canada
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I understand that any such modifications would void the rest of my warranty. It is almost up anyway. I was just interested in peoples opinions of such a procedure. I guess I have gotten the answers I have been looking for. I can either use better caps to reduce the negative effects of a capacitor in this position or bypass them altogether but then I am risking what they are there to prevent in the first place is this about right?
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Old 16th February 2007, 06:08 PM   #6
h_a is offline h_a  Europe
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I wouldn't bypass caps.

Replace with polypropylens if possible, but in general I consider electrolytic's impact as exagerated, but I know this is probably not the answer you wanted. However there are lots of people that say Blackgates are pure crap (including myself because this lousy corp does not even provide datasheets of their caps).

Cheers, Hannes
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Old 16th February 2007, 06:18 PM   #7
ROBSCIX is offline ROBSCIX  Canada
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I have been told by other that for the most part you can bypass caps on the outputs becasue the next device in the line usually has them on the input though correct? I am just considering sound quality. It seems you gain a better sound by removing them aslong as you have no DC problems. THere are alot of opions on this such is why I am asking. I personally know nothing of Black Gates they were suggested to me, SO your saying use a different type the electrolytic for DC blocking caps? Am I using the right term there? DC blocking Caps?
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Old 17th February 2007, 08:37 AM   #8
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Well I really don't want to start a flame war here about Blackgates.

I wouldn't use them. But I would also not expect too much sound improvement by inserting a different cap.

The best alternative - if you really want to change that electrolytic - is for me replacing the elco with a metallized polypropylene (MKP) if that exists in your needed cap size.

These are completely different, non-polarized capacitors and usually huge for uF values.

Sure you can remove that cap at all if the next stage does have one, however for me this is bad practice, since you maybe want to connect some different device and run potentially into problems.

But this is really a topic where everybody has its own opinion.

Have fun! Hannes
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Old 17th February 2007, 04:02 PM   #9
ROBSCIX is offline ROBSCIX  Canada
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Thx for the hlpe guys. I think I have enough info to form my own opinion of what to do in this situation thank you.
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