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I haven't tried with caps yet, I'll try to find some soon.
I've heard contradictory information about input caps on ncore - but most say that it doesn't have them. Could lack of dc blocking caps expain the symptoms?
Ok - by reworking, do you mean just melt all the solder again and maybe add some more?
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The "bangs" you are describing sound very much like you need AC coupling caps. Especially since you said Legato SE output is working fine. It's very easy to make the change and find out. :) Also double check the you have trimmed out all offset. Edited by user Saturday, March 24, 2012 2:35:51 PM(UTC)
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The bangs didn't occur when I fixed the error with switching pin 1 & 2 of the xlr connectors.
How about the issue with no music and only a bit of buzz in the left channel, and music for a short time, then cracks and silence, then music, then silence and so on, with the music parts being shorter and shorter, would capacitors also likely correct this?
I read somewhere else that 4.7-10 uf capacitors would be appropriate, but I read somewhere else that for ncore, close to 1.2 uf should be better. Which should I choose? And which other characteristics should I look for? Could someone link to a good capacitor?
My guess is that I should just put the capacitor between the + terminal on the legato and the + pin on the xlr output - correct? And the + terminal of the capacitor towards the + terminal of the legato?
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Ah ok I missed that part. Well if its only one channel, then likely that channel is faulty. It could be damaged FETs, or any number of things. Is the SE output on the left side exhibiting the same buzz?
It could also be extreme offset on the left side.
You should be fine with 1-22uf film (non-polar) capacitors. You are only testing, so the value is not critical.
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zhai wrote:Ok - by reworking, do you mean just melt all the solder again and maybe add some more? Yes. Preferably add some flux. BTW I've asked Bruno if there are coupling caps on the nCore, just to be sure.
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Ok I'll get a couple of these and try: capsWhen using the headphone out, there is nothing wrong in the slightest, no buzz or anything else, just smooth, flawless music. I'm just guessing, but since the s/e doesn't have any issues, wouldn't that narrow down the problem somewhat? Ok I'll try with the caps first, and if that's not enough, I'll rework the legato. Edited by user Sunday, March 25, 2012 1:18:34 AM(UTC)
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Yep what it means is that your balanced signal should be just fine since you SE signal is completely derived from it. Add the caps and give it a shot. Those caps should be just fine. Edited by user Sunday, March 25, 2012 6:03:09 AM(UTC)
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Ok great! How exactly do I connect the cap? A wire from the plus terminal on legato to one leg, and a wire from the other leg to the xlr plus terminal? Edited by user Sunday, March 25, 2012 10:50:22 AM(UTC)
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Yes. Simply put the cap between the Legato output and the appropriate jack connection.
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Ok I've now tried with caps. And with strange results. I'm using a small circuit called epsilon-24, which controls a push button for powering the system on. This board also shuts off the power under certain circumstances, for instance it seems that if another device draws too much power, it will shut down. So if I turn on my buffalo first, and then turn on the ncore, the buffalo turns off. If I turn on the ncore first and then the buffalo, it seems to be fine. But today, after I had installed the caps, the ncore turned off when I turned on the buffalo. I tried getting power for the ncore from another rail in the house, but the same result. Any ideas why this would happen? I installed 2.2µf caps between the plus terminals on the legato and the xlr plus pins and didn't change anything else. The one time I actually managed to have both turned on at the same time, absolutely nothing could be heard from the speakers. Not even any kind of buzz. After this time I was unable to get the ncore to stay on when I powered on the buffalo.
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You need caps on the -out as well.
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Damn, ok I must have misunderstood. Well, I took the cap I had used for the left +, and put it on the right - instead so I had caps on both + and - on the right channel. I only connected the right xlr cable between the buffalo and the ncore. I wasn't able to get them both to be on at the same time - if I turned one on, the other one turned off automatically.
I tried disconnecting the xlr cable - and then I was able to get them to be turned on at the same time. I tried again with having them on different rails, but that made no difference.
I'm guessing it has to be the epsilon-24 board I have that causes the shutdown? But how is this even possible - it only turns off when there's xlr connection, and how would that board be able to sense that? It's not connected to anything but the mains and a relay.
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Answer from Bruno: the nCore has no coupling caps. If the pre-amp can't deliver a DC-free signal, you should add caps.
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