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Old 3rd June 2013, 10:13 PM   #1
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Default Adding additional Capacitors in PS

I have a couple of 4700uf Audio capacitors laying around and was thinking of adding them to the PS of my sound processor to see if I can get dynamics to improve some. Would it be better to add it before the regulator or after the regulator? The SP is using one 29300V50 regulator for +5v to feed the digital section and one 29300v50 regulator for the +5v analog section. I was thinking of adding one to each.
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Old 3rd June 2013, 11:25 PM   #2
DUG is offline DUG  Canada
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Some regulators have problems with excess caps on outputs.

What does the data sheet say?

What capacitance is there now? ESR of existing caps? ESR of 4700uF caps?
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Old 4th June 2013, 09:51 AM   #3
DF96 is offline DF96  England
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Unlikely to make much difference, unless the original PSU design is poor. If done badly could make things worse by injecting buzz into a ground.
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Old 5th June 2013, 09:19 PM   #4
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I was adding a 1000uF enla Silmic II cap.

http://www.partsconnexion.com/prod_pdf/elna_rfs.pdf

I was thinking of adding

http://www.partsconnexion.com/PDF/e-kg.pdf

I don't see ESR on either of the specs.

I was replacing the regulator with a Belleson super power regulator and I usually put a 1000uf cap on it. The sound is great for a few minutes until the passage gets loud and/or complicated. Then it starts to sound distorted and congested. I put the regular regulator back with the cap and I think it was going the same thing. I need to retest tonight. If that causes he problem I will try the belleson without the cap. I can't quite figure out what is happening. Maybe filling the cap is overloading the ps. Any idea?
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Old 5th June 2013, 09:27 PM   #5
DF96 is offline DF96  England
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What makes you think you have a PSU problem? Your description of the symptoms just sounds like excessive IM, which is more likely to be caused by the circuit itself. Has it always sounded like that i.e. is a fault (to be repaired) or a design flaw (to be improved)?
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Old 5th June 2013, 09:45 PM   #6
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Sorry I'm a noob. IM = intermodular distortion? It sounded fine until I started messing with it. I wanted to upgrade the regulartor to see if I can make it a little better. I figured give it a little more capacitance to make sure the DACs and OP Amps is getting every bit of power it needs quickly. I did that to my BiFrost and it improved the bass(tighter), detail, soundstage (got wider), and dynamics. So my BiFrost sounds a little more dynamic then my sound process that cost 15 times as much and I like the dynamics and what that in my SP. I wanted to see what it would do to a more expensive box with the same family of DAC AK4395 Anthem D2v. BiFrost AK4396. As of know it makes it sound terrible. The first minute or two is good after that it sounds awful. Makes the unmodified system sound wonderful.
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Old 5th June 2013, 10:14 PM   #7
DUG is offline DUG  Canada
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Quote:
Originally Posted by steven2583 View Post
...Makes the unmodified system sound wonderful.
So change it back to unmodified and make ONE change at a time.

If that change does not make it better then remove that change and try something else.

If all changes do not make it better then that will tell you somthing.

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Old 5th June 2013, 10:45 PM   #8
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Yeah, that is what I'm planning to do. I'm going to add the cap to the original regular and see what happens to confirm. Then I will add the new regulator with no additional capacitance. If that works then I will add a smaller cap to see if I can figure out how much I can add and still keep it stable.
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Old 5th June 2013, 10:52 PM   #9
DUG is offline DUG  Canada
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True experimentation.

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Old 6th June 2013, 02:21 AM   #10
dangus is offline dangus  Canada
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Behringer products have a history of cutting corners on power supplies. If channel separation is worse at low frequencies, that suggests that supply rail(s) aren't very stiff and/or the circuits have lousy PSRR.

How about doing some tests using a sound card and software like RMAA to generate some hard numbers? It's not unusual for published specs for digital audio stuff to be fictional... sometimes digital designers just parrot the chip manufacturer's numbers without realizing that those numbers depend on certain conditions being met.

Or, with no signal, or low-level digital source signals (from a test CD), can you hear anything that shouldn't be there? Like digital clicks or buzzes or whines. Same goes for a channel separation test... play a signal on one channel only, then listen to the other at high gain. I suggest using disposable speakers or ideally a test bench amp that happens to have a limiter or AVC in case the next track is 60 dB louder.
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